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Qiao Y, Hu JJ, Hu Y, Duan C, Jiang W, Ma Q, Hong Y, Huang WH, Xia F, Lou X. Detection of Unfolded Cellular Proteins Using Nanochannel Arrays with Probe-Functionalized Outer Surfaces. Angew Chem Int Ed Engl 2023; 62:e202309671. [PMID: 37672359 DOI: 10.1002/anie.202309671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 09/04/2023] [Accepted: 09/05/2023] [Indexed: 09/08/2023]
Abstract
Nanochannel technology has emerged as a powerful tool for label-free and highly sensitive detection of protein folding/unfolding status. However, utilizing the inner walls of a nanochannel array may cause multiple events even for proteins with the same conformation, posing challenges for accurate identification. Herein, we present a platform to detect unfolded proteins through electrical and optical signals using nanochannel arrays with outer-surface probes. The detection principle relies on the specific binding between the maleimide groups in outer-surface probes and the protein cysteine thiols that induce changes in the ionic current and fluorescence intensity responses of the nanochannel array. By taking advantage of this mechanism, the platform has the ability to differentiate folded and unfolded state of proteins based on the exposure of a single cysteine thiol group. The integration of these two signals enhances the reliability and sensitivity of the identification of unfolded protein states and enables the distinction between normal cells and Huntington's disease mutant cells. This study provides an effective approach for the precise analysis of proteins with distinct conformations and holds promise for facilitating the diagnoses of protein conformation-related diseases.
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Affiliation(s)
- Yujuan Qiao
- State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074, China
| | - Jing-Jing Hu
- State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074, China
| | - Yuxin Hu
- State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074, China
| | - Chong Duan
- State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074, China
| | - Wenlian Jiang
- State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074, China
| | - Qun Ma
- State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074, China
| | - Yuning Hong
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, VIC 3086, Australia
| | - Wei Hua Huang
- Sauvage Center for Molecular Sciences, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 430072, China
| | - Fan Xia
- State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074, China
| | - Xiaoding Lou
- State Key Laboratory of Biogeology and Environmental Geology, Engineering Research Center of Nano-Geomaterials of Ministry of Education, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan, 430074, China
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2
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Ubbiali D, Fratini M, Piersimoni L, Ihling CH, Kipping M, Heilmann I, Iacobucci C, Sinz A. Direct Observation of "Elongated" Conformational States in α-Synuclein upon Liquid-Liquid Phase Separation. Angew Chem Int Ed Engl 2022; 61:e202205726. [PMID: 36115020 PMCID: PMC9828221 DOI: 10.1002/anie.202205726] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Indexed: 01/12/2023]
Abstract
α-Synuclein (α-syn) is an intrinsically disordered protein (IDP) that undergoes liquid-liquid phase separation (LLPS), fibrillation, and forms insoluble intracellular Lewy bodies in neurons, which are the hallmark of Parkinson's Disease (PD). Neurotoxicity precedes the formation of aggregates and might be related to α-syn LLPS. The molecular mechanisms underlying the early stages of LLPS are still elusive. To obtain structural insights into α-syn upon LLPS, we take advantage of cross-linking/mass spectrometry (XL-MS) and introduce an innovative approach, termed COMPASS (COMPetitive PAiring StatisticS). In this work, we show that the conformational ensemble of α-syn shifts from a "hairpin-like" structure towards more "elongated" conformational states upon LLPS. We obtain insights into the critical initial stages of LLPS and establish a novel mass spectrometry-based approach that will aid to solve open questions in LLPS structural biology.
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Affiliation(s)
- Daniele Ubbiali
- Department of Pharmaceutical Chemistry and Bioanalytics, Institute of PharmacyMartin Luther University Halle-WittenbergKurt-Mothes-Str. 306120Halle/SaaleGermany,Center for Structural Mass SpectrometryMartin Luther University Halle-WittenbergKurt-Mothes-Str. 306120Halle/SaaleGermany
| | - Marta Fratini
- Department of Plant BiochemistryCharles Tanford Protein CenterInstitute for Biochemistry and BiotechnologyMartin-Luther University Halle-WittenbergKurt-Mothes-Str. 306120Halle/SaaleGermany
| | - Lolita Piersimoni
- Department of Pharmaceutical Chemistry and Bioanalytics, Institute of PharmacyMartin Luther University Halle-WittenbergKurt-Mothes-Str. 306120Halle/SaaleGermany,Center for Structural Mass SpectrometryMartin Luther University Halle-WittenbergKurt-Mothes-Str. 306120Halle/SaaleGermany
| | - Christian H. Ihling
- Department of Pharmaceutical Chemistry and Bioanalytics, Institute of PharmacyMartin Luther University Halle-WittenbergKurt-Mothes-Str. 306120Halle/SaaleGermany,Center for Structural Mass SpectrometryMartin Luther University Halle-WittenbergKurt-Mothes-Str. 306120Halle/SaaleGermany
| | - Marc Kipping
- Department of Pharmaceutical Chemistry and Bioanalytics, Institute of PharmacyMartin Luther University Halle-WittenbergKurt-Mothes-Str. 306120Halle/SaaleGermany,Center for Structural Mass SpectrometryMartin Luther University Halle-WittenbergKurt-Mothes-Str. 306120Halle/SaaleGermany
| | - Ingo Heilmann
- Department of Plant BiochemistryCharles Tanford Protein CenterInstitute for Biochemistry and BiotechnologyMartin-Luther University Halle-WittenbergKurt-Mothes-Str. 306120Halle/SaaleGermany
| | - Claudio Iacobucci
- Department of Pharmaceutical Chemistry and Bioanalytics, Institute of PharmacyMartin Luther University Halle-WittenbergKurt-Mothes-Str. 306120Halle/SaaleGermany,Center for Structural Mass SpectrometryMartin Luther University Halle-WittenbergKurt-Mothes-Str. 306120Halle/SaaleGermany,Department of Physical and Chemical SciencesUniversity of L'AquilaVia Vetoio, Coppito67100L'AquilaItaly
| | - Andrea Sinz
- Department of Pharmaceutical Chemistry and Bioanalytics, Institute of PharmacyMartin Luther University Halle-WittenbergKurt-Mothes-Str. 306120Halle/SaaleGermany,Center for Structural Mass SpectrometryMartin Luther University Halle-WittenbergKurt-Mothes-Str. 306120Halle/SaaleGermany
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3
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Trcka F, Durech M, Vankova P, Chmelik J, Martinkova V, Hausner J, Kadek A, Marcoux J, Klumpler T, Vojtesek B, Muller P, Man P. Human Stress-inducible Hsp70 Has a High Propensity to Form ATP-dependent Antiparallel Dimers That Are Differentially Regulated by Cochaperone Binding. Mol Cell Proteomics 2019; 18:320-337. [PMID: 30459217 PMCID: PMC6356074 DOI: 10.1074/mcp.ra118.001044] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 11/09/2018] [Indexed: 12/23/2022] Open
Abstract
Eukaryotic protein homeostasis (proteostasis) is largely dependent on the action of highly conserved Hsp70 molecular chaperones. Recent evidence indicates that, apart from conserved molecular allostery, Hsp70 proteins have retained and adapted the ability to assemble as functionally relevant ATP-bound dimers throughout evolution. Here, we have compared the ATP-dependent dimerization of DnaK, human stress-inducible Hsp70, Hsc70 and BiP Hsp70 proteins, showing that their dimerization propensities differ, with stress-inducible Hsp70 being predominantly dimeric in the presence of ATP. Structural analyses using hydrogen/deuterium exchange mass spectrometry, native electrospray ionization mass spectrometry and small-angle X-ray scattering revealed that stress-inducible Hsp70 assembles in solution as an antiparallel dimer with the intermolecular interface closely resembling the ATP-bound dimer interfaces captured in DnaK and BiP crystal structures. ATP-dependent dimerization of stress-inducible Hsp70 is necessary for its efficient interaction with Hsp40, as shown by experiments with dimerization-deficient mutants. Moreover, dimerization of ATP-bound Hsp70 is required for its participation in high molecular weight protein complexes detected ex vivo, supporting its functional role in vivo As human cytosolic Hsp70 can interact with tetratricopeptide repeat (TPR) domain containing cochaperones, we tested the interaction of Hsp70 ATP-dependent dimers with Chip and Tomm34 cochaperones. Although Chip associates with intact Hsp70 dimers to form a larger complex, binding of Tomm34 disrupts the Hsp70 dimer and this event plays an important role in Hsp70 activity regulation. In summary, this study provides structural evidence of robust ATP-dependent antiparallel dimerization of human inducible Hsp70 protein and suggests a novel role of TPR domain cochaperones in multichaperone complexes involving Hsp70 ATP-bound dimers.
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Affiliation(s)
- Filip Trcka
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53 Brno, Czech Republic
| | - Michal Durech
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53 Brno, Czech Republic
| | - Pavla Vankova
- BioCeV - Institute of Microbiology of the Czech Academy of Sciences, v.v.i., Prumyslova 595, 252 50 Vestec, Czech Republic;; Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 43 Prague, Czech Republic
| | - Josef Chmelik
- BioCeV - Institute of Microbiology of the Czech Academy of Sciences, v.v.i., Prumyslova 595, 252 50 Vestec, Czech Republic;; Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 43 Prague, Czech Republic
| | - Veronika Martinkova
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53 Brno, Czech Republic
| | - Jiri Hausner
- BioCeV - Institute of Microbiology of the Czech Academy of Sciences, v.v.i., Prumyslova 595, 252 50 Vestec, Czech Republic;; Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 43 Prague, Czech Republic
| | - Alan Kadek
- BioCeV - Institute of Microbiology of the Czech Academy of Sciences, v.v.i., Prumyslova 595, 252 50 Vestec, Czech Republic;; Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 43 Prague, Czech Republic
| | - Julien Marcoux
- Institut de Pharmacologie et de Biologie Structurale, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Tomas Klumpler
- CEITEC-Central European Institute of Technology, Masaryk University, 625 00 Brno, Czech Republic
| | - Borivoj Vojtesek
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53 Brno, Czech Republic
| | - Petr Muller
- Regional Centre for Applied Molecular Oncology, Masaryk Memorial Cancer Institute, Zluty kopec 7, 656 53 Brno, Czech Republic;.
| | - Petr Man
- BioCeV - Institute of Microbiology of the Czech Academy of Sciences, v.v.i., Prumyslova 595, 252 50 Vestec, Czech Republic;; Department of Biochemistry, Faculty of Science, Charles University in Prague, Hlavova 8, 128 43 Prague, Czech Republic;.
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4
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Volkening JD, Stecker KE, Sussman MR. Proteome-wide Analysis of Protein Thermal Stability in the Model Higher Plant Arabidopsis thaliana. Mol Cell Proteomics 2019; 18:308-319. [PMID: 30401684 PMCID: PMC6356070 DOI: 10.1074/mcp.ra118.001124] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Indexed: 12/16/2022] Open
Abstract
Modern tandem MS-based sequencing technologies allow for the parallel measurement of concentration and covalent modifications for proteins within a complex sample. Recently, this capability has been extended to probe a proteome's three-dimensional structure and conformational state by determining the thermal denaturation profile of thousands of proteins simultaneously. Although many animals and their resident microbes exist under a relatively narrow, regulated physiological temperature range, plants take on the often widely ranging temperature of their surroundings, possibly influencing the evolution of protein thermal stability. In this report we present the first in-depth look at the thermal proteome of a plant species, the model organism Arabidopsis thaliana By profiling the melting curves of over 1700 Arabidopsis proteins using six biological replicates, we have observed significant correlation between protein thermostability and several known protein characteristics, including molecular weight and the composition ratio of charged to polar amino acids. We also report on a divergence of the thermostability of the core and regulatory domains of the plant 26S proteasome that may reflect a unique property of the way protein turnover is regulated during temperature stress. Lastly, the highly replicated database of Arabidopsis melting temperatures reported herein provides baseline data on the variability of protein behavior in the assay. Unfolding behavior and experiment-to-experiment variability were observed to be protein-specific traits, and thus this data can serve to inform the design and interpretation of future targeted assays to probe the conformational status of proteins from plants exposed to different chemical, environmental and genetic challenges.
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Affiliation(s)
- Jeremy D Volkening
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706
| | - Kelly E Stecker
- Biomolecular Mass Spectrometry and Proteomics, Utrecht University, Utrecht, Netherlands
| | - Michael R Sussman
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706;.
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5
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Fatou B, Ziskind M, Saudemont P, Quanico J, Focsa C, Salzet M, Fournier I. Remote Atmospheric Pressure Infrared Matrix-Assisted Laser Desorption-Ionization Mass Spectrometry (Remote IR-MALDI MS) of Proteins. Mol Cell Proteomics 2018; 17:1637-1649. [PMID: 29653959 DOI: 10.1074/mcp.tir117.000582] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 04/12/2018] [Indexed: 11/06/2022] Open
Abstract
Remote Infrared Matrix-Assisted Laser Desorption/Ionization (Remote IR-MALDI) system using tissue endogenous water as matrix was shown to enable in vivo real-time mass spectrometry analysis with minimal invasiveness. Initially the system was used to detect metabolites and lipids. Here, we demonstrate its capability to detect and analyze peptides and proteins. Very interestingly, the corresponding mass spectra show ESI-like charge state distribution, opening many applications for structural elucidation to be performed in real-time by Top-Down strategy. The charge states show no dependence toward laser wavelength or length of the transfer tube. Indeed, remote analysis can be performed 5 m away from the mass spectrometer without modification of spectra. On the contrary, addition of glycerol to water shift the charge state distributions toward even higher charge states. The desorption/ionization process is very soft, allowing to maintain protein conformation as in ESI. Observation of proteins and similar spectral features on tissue, when protein standards are deposited on raw tissue pieces, could potentially open the way to their direct analysis from biological samples. This also brings interesting features that could contribute to the understanding of IR MALDI ionization mechanism.
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Affiliation(s)
- Benoit Fatou
- From the ‡Université de Lille, INSERM, U1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse (PRISM), F-59000 Lille, France.,§Université de Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000 Lille, France
| | - Michael Ziskind
- §Université de Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000 Lille, France
| | - Philippe Saudemont
- From the ‡Université de Lille, INSERM, U1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse (PRISM), F-59000 Lille, France.,¶SATT Nord, Immeuble Central Gare, 4e étage, 25, Avenue Charles St Venant, F-59800 Lille, France
| | - Jusal Quanico
- From the ‡Université de Lille, INSERM, U1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse (PRISM), F-59000 Lille, France.,§Université de Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000 Lille, France
| | - Cristian Focsa
- §Université de Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000 Lille, France
| | - Michel Salzet
- From the ‡Université de Lille, INSERM, U1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse (PRISM), F-59000 Lille, France
| | - Isabelle Fournier
- From the ‡Université de Lille, INSERM, U1192 - Laboratoire Protéomique, Réponse Inflammatoire et Spectrométrie de Masse (PRISM), F-59000 Lille, France;
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6
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Kalas V, Pinkner JS, Hannan TJ, Hibbing ME, Dodson KW, Holehouse AS, Zhang H, Tolia NH, Gross ML, Pappu RV, Janetka J, Hultgren SJ. Evolutionary fine-tuning of conformational ensembles in FimH during host-pathogen interactions. Sci Adv 2017; 3:e1601944. [PMID: 28246638 PMCID: PMC5302871 DOI: 10.1126/sciadv.1601944] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Accepted: 01/25/2017] [Indexed: 05/05/2023]
Abstract
Positive selection in the two-domain type 1 pilus adhesin FimH enhances Escherichia coli fitness in urinary tract infection (UTI). We report a comprehensive atomic-level view of FimH in two-state conformational ensembles in solution, composed of one low-affinity tense (T) and multiple high-affinity relaxed (R) conformations. Positively selected residues allosterically modulate the equilibrium between these two conformational states, each of which engages mannose through distinct binding orientations. A FimH variant that only adopts the R state is severely attenuated early in a mouse model of uncomplicated UTI but is proficient at colonizing catheterized bladders in vivo or bladder transitional-like epithelial cells in vitro. Thus, the bladder habitat has barrier(s) to R state-mediated colonization possibly conferred by the terminally differentiated bladder epithelium and/or decoy receptors in urine. Together, our studies reveal the conformational landscape in solution, binding mechanisms, and adhesive strength of an allosteric two-domain adhesin that evolved "moderate" affinity to optimize persistence in the bladder during UTI.
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Affiliation(s)
- Vasilios Kalas
- Center for Women’s Infectious Disease Research, Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jerome S. Pinkner
- Center for Women’s Infectious Disease Research, Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Thomas J. Hannan
- Center for Women’s Infectious Disease Research, Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael E. Hibbing
- Center for Women’s Infectious Disease Research, Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Karen W. Dodson
- Center for Women’s Infectious Disease Research, Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Alex S. Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Hao Zhang
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Niraj H. Tolia
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Michael L. Gross
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Rohit V. Pappu
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Biomedical Engineering and Center for Biological Systems Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - James Janetka
- Department of Chemistry, Washington University in St. Louis, St. Louis, MO 63130, USA
| | - Scott J. Hultgren
- Center for Women’s Infectious Disease Research, Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, MO 63110, USA
- Corresponding author.
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7
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Bjerregaard H, Severinsen K, Said S, Wiborg O, Sinning S. A dualistic conformational response to substrate binding in the human serotonin transporter reveals a high affinity state for serotonin. J Biol Chem 2015; 290:7747-55. [PMID: 25614630 DOI: 10.1074/jbc.m114.573477] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Serotonergic neurotransmission is modulated by the membrane-embedded serotonin transporter (SERT). SERT mediates the reuptake of serotonin into the presynaptic neurons. Conformational changes in SERT occur upon binding of ions and substrate and are crucial for translocation of serotonin across the membrane. Our understanding of these conformational changes is mainly based on crystal structures of a bacterial homolog in various conformations, derived homology models of eukaryotic neurotransmitter transporters, and substituted cysteine accessibility method of SERT. However, the dynamic changes that occur in the human SERT upon binding of ions, the translocation of substrate, and the role of cholesterol in this interplay are not fully elucidated. Here we show that serotonin induces a dualistic conformational response in SERT. We exploited the substituted cysteine scanning method under conditions that were sensitized to detect a more outward-facing conformation of SERT. We found a novel high affinity outward-facing conformational state of the human SERT induced by serotonin. The ionic requirements for this new conformational response to serotonin mirror the ionic requirements for translocation. Furthermore, we found that membrane cholesterol plays a role in the dualistic conformational response in SERT induced by serotonin. Our results indicate the existence of a subpopulation of SERT responding differently to serotonin binding than hitherto believed and that membrane cholesterol plays a role in this subpopulation of SERT.
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Affiliation(s)
- Henriette Bjerregaard
- From the Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus University Hospital, Skovagervej 2, DK-8240 Risskov, Denmark
| | - Kasper Severinsen
- From the Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus University Hospital, Skovagervej 2, DK-8240 Risskov, Denmark
| | - Saida Said
- From the Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus University Hospital, Skovagervej 2, DK-8240 Risskov, Denmark
| | - Ove Wiborg
- From the Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus University Hospital, Skovagervej 2, DK-8240 Risskov, Denmark
| | - Steffen Sinning
- From the Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus University Hospital, Skovagervej 2, DK-8240 Risskov, Denmark
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8
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Abstract
Despite extensive study, how retinal enters and exits the visual G protein-coupled receptor rhodopsin remains unclear. One clue may lie in two openings between transmembrane helix 1 (TM1) and TM7 and between TM5 and TM6 in the active receptor structure. Recently, retinal has been proposed to enter the inactive apoprotein opsin (ops) through these holes when the receptor transiently adopts the active opsin conformation (ops*). Here, we directly test this "transient activation" hypothesis using a fluorescence-based approach to measure rates of retinal binding to samples containing differing relative fractions of ops and ops*. In contrast to what the transient activation hypothesis model would predict, we found that binding for the inverse agonist, 11-cis-retinal (11CR), slowed when the sample contained more ops* (produced using M257Y, a constitutively activating mutation). Interestingly, the increased presence of ops* allowed for binding of the agonist, all-trans-retinal (ATR), whereas WT opsin showed no binding. Shifting the conformational equilibrium toward even more ops* using a G protein peptide mimic (either free in solution or fused to the receptor) accelerated the rate of ATR binding and slowed 11CR binding. An arrestin peptide mimic showed little effect on 11CR binding; however, it stabilized opsin · ATR complexes. The TM5/TM6 hole is apparently not involved in this conformational selection. Increasing its size by mutagenesis did not enable ATR binding but instead slowed 11CR binding, suggesting that it may play a role in trapping 11CR. In summary, our results indicate that conformational selection dictates stable retinal binding, which we propose involves ATR and 11CR binding to different states, the latter a previously unidentified, open-but-inactive conformation.
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Affiliation(s)
- Christopher T Schafer
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239-3098
| | - David L Farrens
- From the Department of Biochemistry and Molecular Biology, Oregon Health and Science University, Portland, Oregon 97239-3098
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9
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Richarme G, Mihoub M, Dairou J, Bui LC, Leger T, Lamouri A. Parkinsonism-associated protein DJ-1/Park7 is a major protein deglycase that repairs methylglyoxal- and glyoxal-glycated cysteine, arginine, and lysine residues. J Biol Chem 2014; 290:1885-97. [PMID: 25416785 DOI: 10.1074/jbc.m114.597815] [Citation(s) in RCA: 193] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Glycation is an inevitable nonenzymatic covalent reaction between proteins and endogenous reducing sugars or dicarbonyls (methylglyoxal, glyoxal) that results in protein inactivation. DJ-1 was reported to be a multifunctional oxidative stress response protein with poorly defined function. Here, we show that human DJ-1 is a protein deglycase that repairs methylglyoxal- and glyoxal-glycated amino acids and proteins by acting on early glycation intermediates and releases repaired proteins and lactate or glycolate, respectively. DJ-1 deglycates cysteines, arginines, and lysines (the three major glycated amino acids) of serum albumin, glyceraldehyde-3-phosphate dehydrogenase, aldolase, and aspartate aminotransferase and thus reactivates these proteins. DJ-1 prevented protein glycation in an Escherichia coli mutant deficient in the DJ-1 homolog YajL and restored cell viability in glucose-containing media. These results suggest that DJ-1-associated Parkinsonism results from excessive protein glycation and establishes DJ-1 as a major anti-glycation and anti-aging protein.
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Affiliation(s)
- Gilbert Richarme
- From the Stress Molecules, Institut Jacques Monod, Université Paris 7, CNRS UMR 7592, 75013 Paris, France,
| | - Mouadh Mihoub
- From the Stress Molecules, Institut Jacques Monod, Université Paris 7, CNRS UMR 7592, 75013 Paris, France
| | - Julien Dairou
- the Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative UMR 8251 CNRS, Bioprofiler Facility, F-75205, Paris, France
| | - Linh Chi Bui
- the Université Paris Diderot, Sorbonne Paris Cité, Unité de Biologie Fonctionnelle et Adaptative UMR 8251 CNRS, Bioprofiler Facility, F-75205, Paris, France
| | - Thibaut Leger
- the Proteomics Facility, Institut Jacques Monod, Université Paris 7, CNRS, UMR 7592, 75013 Paris, France, and
| | - Aazdine Lamouri
- the Université Paris Diderot, Sorbonne Paris Cite, ITODYS, UMR 7086 CNRS, 75013 Paris, France
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10
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Falcon B, Cavallini A, Angers R, Glover S, Murray TK, Barnham L, Jackson S, O'Neill MJ, Isaacs AM, Hutton ML, Szekeres PG, Goedert M, Bose S. Conformation determines the seeding potencies of native and recombinant Tau aggregates. J Biol Chem 2014; 290:1049-65. [PMID: 25406315 PMCID: PMC4294473 DOI: 10.1074/jbc.m114.589309] [Citation(s) in RCA: 192] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Intracellular Tau inclusions are a pathological hallmark of several neurodegenerative diseases, collectively known as the tauopathies. They include Alzheimer disease, tangle-only dementia, Pick disease, argyrophilic grain disease, chronic traumatic encephalopathy, progressive supranuclear palsy, and corticobasal degeneration. Tau pathology appears to spread through intercellular propagation, requiring the formation of assembled “prion-like” species. Several cell and animal models have been described that recapitulate aspects of this phenomenon. However, the molecular characteristics of seed-competent Tau remain unclear. Here, we have used a cell model to understand the relationships between Tau structure/phosphorylation and seeding by aggregated Tau species from the brains of mice transgenic for human mutant P301S Tau and full-length aggregated recombinant P301S Tau. Deletion of motifs 275VQIINK280 and 306VQIVYK311 abolished the seeding activity of recombinant full-length Tau, suggesting that its aggregation was necessary for seeding. We describe conformational differences between native and synthetic Tau aggregates that may account for the higher seeding activity of native assembled Tau. When added to aggregated Tau seeds from the brains of mice transgenic for P301S Tau, soluble recombinant Tau aggregated and acquired the molecular properties of aggregated Tau from transgenic mouse brain. We show that seeding is conferred by aggregated Tau that enters cells through macropinocytosis and seeds the assembly of endogenous Tau into filaments.
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Affiliation(s)
- Benjamin Falcon
- From the Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom
| | - Annalisa Cavallini
- Eli Lilly and Co., Erl Wood Manor, Windlesham, Surrey GU20 6PH, United Kingdom, and
| | - Rachel Angers
- From the Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom, Eli Lilly and Co., Erl Wood Manor, Windlesham, Surrey GU20 6PH, United Kingdom, and
| | - Sarah Glover
- Eli Lilly and Co., Erl Wood Manor, Windlesham, Surrey GU20 6PH, United Kingdom, and
| | - Tracey K Murray
- Eli Lilly and Co., Erl Wood Manor, Windlesham, Surrey GU20 6PH, United Kingdom, and
| | - Luanda Barnham
- Eli Lilly and Co., Erl Wood Manor, Windlesham, Surrey GU20 6PH, United Kingdom, and
| | - Samuel Jackson
- Eli Lilly and Co., Erl Wood Manor, Windlesham, Surrey GU20 6PH, United Kingdom, and
| | - Michael J O'Neill
- Eli Lilly and Co., Erl Wood Manor, Windlesham, Surrey GU20 6PH, United Kingdom, and
| | - Adrian M Isaacs
- the UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
| | - Michael L Hutton
- Eli Lilly and Co., Erl Wood Manor, Windlesham, Surrey GU20 6PH, United Kingdom, and
| | - Philip G Szekeres
- Eli Lilly and Co., Erl Wood Manor, Windlesham, Surrey GU20 6PH, United Kingdom, and
| | - Michel Goedert
- From the Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, United Kingdom,
| | - Suchira Bose
- Eli Lilly and Co., Erl Wood Manor, Windlesham, Surrey GU20 6PH, United Kingdom, and
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11
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Lai RPJ, Hock M, Radzimanowski J, Tonks P, Hulsik DL, Effantin G, Seilly DJ, Dreja H, Kliche A, Wagner R, Barnett SW, Tumba N, Morris L, LaBranche CC, Montefiori DC, Seaman MS, Heeney JL, Weissenhorn W. A fusion intermediate gp41 immunogen elicits neutralizing antibodies to HIV-1. J Biol Chem 2014; 289:29912-26. [PMID: 25160627 PMCID: PMC4208001 DOI: 10.1074/jbc.m114.569566] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Revised: 08/01/2014] [Indexed: 11/06/2022] Open
Abstract
The membrane-proximal external region (MPER) of the human immunodeficiency virus, type 1 (HIV-1) envelope glycoprotein subunit gp41 is targeted by potent broadly neutralizing antibodies 2F5, 4E10, and 10E8. These antibodies recognize linear epitopes and have been suggested to target the fusion intermediate conformation of gp41 that bridges viral and cellular membranes. Anti-MPER antibodies exert different degrees of membrane interaction, which is considered to be the limiting factor for the generation of such antibodies by immunization. Here we characterize a fusion intermediate conformation of gp41 (gp41(int)-Cys) and show that it folds into an elongated ∼ 12-nm-long extended structure based on small angle x-ray scattering data. Gp41(int)-Cys was covalently linked to liposomes via its C-terminal cysteine and used as immunogen. The gp41(int)-Cys proteoliposomes were administered alone or in prime-boost regimen with trimeric envelope gp140(CA018) in guinea pigs and elicited high anti-gp41 IgG titers. The sera interacted with a peptide spanning the MPER region, demonstrated competition with broadly neutralizing antibodies 2F5 and 4E10, and exerted modest lipid binding, indicating the presence of MPER-specific antibodies. Although the neutralization potency generated solely by gp140(CA018) was higher than that induced by gp41(int)-Cys, the majority of animals immunized with gp41(int)-Cys proteoliposomes induced modest breadth and potency in neutralizing tier 1 pseudoviruses and replication-competent simian/human immunodeficiency viruses in the TZM-bl assay as well as responses against tier 2 HIV-1 in the A3R5 neutralization assay. Our data thus demonstrate that liposomal gp41 MPER formulation can induce neutralization activity, and the strategy serves to improve breadth and potency of such antibodies by improved vaccination protocols.
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Affiliation(s)
- Rachel P J Lai
- From the Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom
| | - Miriam Hock
- Université Grenoble Alpes, Unit of Virus Host Cell Interactions (UVHCI), F-38000 Grenoble, France, CNRS, UVHCI, F-38000 Grenoble, France
| | - Jens Radzimanowski
- Université Grenoble Alpes, Unit of Virus Host Cell Interactions (UVHCI), F-38000 Grenoble, France, CNRS, UVHCI, F-38000 Grenoble, France
| | - Paul Tonks
- From the Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom
| | - David Lutje Hulsik
- Université Grenoble Alpes, Unit of Virus Host Cell Interactions (UVHCI), F-38000 Grenoble, France, CNRS, UVHCI, F-38000 Grenoble, France
| | - Gregory Effantin
- Université Grenoble Alpes, Unit of Virus Host Cell Interactions (UVHCI), F-38000 Grenoble, France, CNRS, UVHCI, F-38000 Grenoble, France
| | - David J Seilly
- From the Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom
| | - Hanna Dreja
- From the Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom
| | - Alexander Kliche
- Institute of Medical Microbiology and Hygiene, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Ralf Wagner
- Institute of Medical Microbiology and Hygiene, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Susan W Barnett
- Novartis Vaccines and Diagnostics Inc., Cambridge, Massachusetts 02139
| | - Nancy Tumba
- National Institute for Communicable Diseases, Centre for HIV and Sexually Transmitted Infections, 1 Modderfontein Road, Sandringham 2131, South Africa
| | - Lynn Morris
- National Institute for Communicable Diseases, Centre for HIV and Sexually Transmitted Infections, 1 Modderfontein Road, Sandringham 2131, South Africa
| | - Celia C LaBranche
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, and
| | - David C Montefiori
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, and
| | - Michael S Seaman
- Division of Viral Pathogenesis, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115
| | - Jonathan L Heeney
- From the Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, United Kingdom,
| | - Winfried Weissenhorn
- Université Grenoble Alpes, Unit of Virus Host Cell Interactions (UVHCI), F-38000 Grenoble, France, CNRS, UVHCI, F-38000 Grenoble, France,
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12
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Queval R, Papin C, Dalvai M, Bystricky K, Humbert O. Reptin and Pontin oligomerization and activity are modulated through histone H3 N-terminal tail interaction. J Biol Chem 2014; 289:33999-4012. [PMID: 25336637 DOI: 10.1074/jbc.m114.576785] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Pontin/RUVBL1 and Reptin/RUVBL2 are DNA-dependent ATPases involved in numerous cellular processes and are essential components of chromatin remodeling complexes and transcription factor assemblies. However, their existence as monomeric and oligomeric forms with differential activity in vivo reflects their versatility. Using a biochemical approach, we have studied the role of the nucleosome core particle and histone N-terminal tail modifications in the assembly and enzymatic activities of Reptin/Pontin. We demonstrate that purified Reptin and Pontin form stable complexes with nucleosomes. The ATPase activity of Reptin/Pontin is modulated by acetylation and methylation of the histone H3 N terminus. In vivo, association of Reptin with the progesterone receptor gene promoter is concomitant with changes in H3 marks of the surrounding nucleosomes. Furthermore, the presence of H3 tail peptides regulates the monomer-oligomer transition of Reptin/Pontin. Proteins that are pulled down by monomeric Reptin/Pontin differ from those that can bind to hexamers. We propose that changes in the oligomeric status of Reptin/Pontin create a platform that brings specific cofactors close to gene promoters and loads regulatory factors to establish an active state of chromatin.
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Affiliation(s)
- Richard Queval
- From the Laboratoire de Biologie Moléculaire Eucaryote, CNRS/UMR 5099, F-31062 Toulouse Cedex, the Université de Toulouse, UPS, 31062 Toulouse Cedex, and
| | - Christophe Papin
- the Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM, Université de Strasbourg, 67404 Illkirch Cedex, France
| | - Mathieu Dalvai
- From the Laboratoire de Biologie Moléculaire Eucaryote, CNRS/UMR 5099, F-31062 Toulouse Cedex, the Université de Toulouse, UPS, 31062 Toulouse Cedex, and
| | - Kerstin Bystricky
- From the Laboratoire de Biologie Moléculaire Eucaryote, CNRS/UMR 5099, F-31062 Toulouse Cedex, the Université de Toulouse, UPS, 31062 Toulouse Cedex, and
| | - Odile Humbert
- From the Laboratoire de Biologie Moléculaire Eucaryote, CNRS/UMR 5099, F-31062 Toulouse Cedex, the Université de Toulouse, UPS, 31062 Toulouse Cedex, and
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13
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Rivera-Najera LY, Saab-Rincón G, Battaglia M, Amero C, Pulido NO, García-Hernández E, Solórzano RM, Reyes JL, Covarrubias AA. A group 6 late embryogenesis abundant protein from common bean is a disordered protein with extended helical structure and oligomer-forming properties. J Biol Chem 2014; 289:31995-32009. [PMID: 25271167 DOI: 10.1074/jbc.m114.583369] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Late embryogenesis-abundant proteins accumulate to high levels in dry seeds. Some of them also accumulate in response to water deficit in vegetative tissues, which leads to a remarkable association between their presence and low water availability conditions. A major sub-group of these proteins, also known as typical LEA proteins, shows high hydrophilicity and a high percentage of glycine and other small amino acid residues, distinctive physicochemical properties that predict a high content of structural disorder. Although all typical LEA proteins share these characteristics, seven groups can be distinguished by sequence similarity, indicating structural and functional diversity among them. Some of these groups have been extensively studied; however, others require a more detailed analysis to advance in their functional understanding. In this work, we report the structural characterization of a group 6 LEA protein from a common bean (Phaseolus vulgaris L.) (PvLEA6) by circular dichroism and nuclear magnetic resonance showing that it is a disordered protein in aqueous solution. Using the same techniques, we show that despite its unstructured nature, the addition of trifluoroethanol exhibited an intrinsic potential in this protein to gain helicity. This property was also promoted by high osmotic potentials or molecular crowding. Furthermore, we demonstrate that PvLEA6 protein is able to form soluble homo-oligomeric complexes that also show high levels of structural disorder. The association between PvLEA6 monomers to form dimers was shown to occur in plant cells by bimolecular fluorescence complementation, pointing to the in vivo functional relevance of this association.
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Affiliation(s)
- Lucero Y Rivera-Najera
- Departamentos de Biología Molecular de Plantas and Universidad Nacional Autónoma de México, Apdo. Postal 510-3, 62250 Cuernavaca, Mor
| | - Gloria Saab-Rincón
- Departamentos de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, 62250 Cuernavaca, Mor
| | - Marina Battaglia
- Departamentos de Biología Molecular de Plantas and Universidad Nacional Autónoma de México, Apdo. Postal 510-3, 62250 Cuernavaca, Mor
| | - Carlos Amero
- Centro de Investigaciones Químicas, Universidad Autónoma del Estado de Morelos, Av. Universidad No. 1001, Col Chamilpa, 62209 Cuernavaca, Morelos, and
| | - Nancy O Pulido
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México 04510, D. F. México
| | - Enrique García-Hernández
- Instituto de Química, Universidad Nacional Autónoma de México, Circuito Exterior, Ciudad Universitaria, México 04510, D. F. México
| | - Rosa M Solórzano
- Departamentos de Biología Molecular de Plantas and Universidad Nacional Autónoma de México, Apdo. Postal 510-3, 62250 Cuernavaca, Mor
| | - José L Reyes
- Departamentos de Biología Molecular de Plantas and Universidad Nacional Autónoma de México, Apdo. Postal 510-3, 62250 Cuernavaca, Mor
| | - Alejandra A Covarrubias
- Departamentos de Biología Molecular de Plantas and Universidad Nacional Autónoma de México, Apdo. Postal 510-3, 62250 Cuernavaca, Mor..
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14
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Racca JD, Chen YS, Maloy JD, Wickramasinghe N, Phillips NB, Weiss MA. Structure-function relationships in human testis-determining factor SRY: an aromatic buttress underlies the specific DNA-bending surface of a high mobility group (HMG) box. J Biol Chem 2014; 289:32410-29. [PMID: 25258310 DOI: 10.1074/jbc.m114.597526] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human testis determination is initiated by SRY, a Y-encoded architectural transcription factor. Mutations in SRY cause 46 XY gonadal dysgenesis with female somatic phenotype (Swyer syndrome) and confer a high risk of malignancy (gonadoblastoma). Such mutations cluster in the SRY high mobility group (HMG) box, a conserved motif of specific DNA binding and bending. To explore structure-function relationships, we constructed all possible substitutions at a site of clinical mutation (W70L). Our studies thus focused on a core aromatic residue (position 15 of the consensus HMG box) that is invariant among SRY-related HMG box transcription factors (the SOX family) and conserved as aromatic (Phe or Tyr) among other sequence-specific boxes. In a yeast one-hybrid system sensitive to specific SRY-DNA binding, the variant domains exhibited reduced (Phe and Tyr) or absent activity (the remaining 17 substitutions). Representative nonpolar variants with partial or absent activity (Tyr, Phe, Leu, and Ala in order of decreasing side-chain volume) were chosen for study in vitro and in mammalian cell culture. The clinical mutation (Leu) was found to markedly impair multiple biochemical and cellular activities as respectively probed through the following: (i) in vitro assays of specific DNA binding and protein stability, and (ii) cell culture-based assays of proteosomal degradation, nuclear import, enhancer DNA occupancy, and SRY-dependent transcriptional activation. Surprisingly, however, DNA bending is robust to this or the related Ala substitution that profoundly impairs box stability. Together, our findings demonstrate that the folding, trafficking, and gene-regulatory function of SRY requires an invariant aromatic "buttress" beneath its specific DNA-bending surface.
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Affiliation(s)
- Joseph D Racca
- From the Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Yen-Shan Chen
- From the Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - James D Maloy
- From the Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Nalinda Wickramasinghe
- From the Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Nelson B Phillips
- From the Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
| | - Michael A Weiss
- From the Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio 44106
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15
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Chu NK, Shabbir W, Bove-Fenderson E, Araman C, Lemmens-Gruber R, Harris DA, Becker CFW. A C-terminal membrane anchor affects the interactions of prion proteins with lipid membranes. J Biol Chem 2014; 289:30144-60. [PMID: 25217642 DOI: 10.1074/jbc.m114.587345] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Membrane attachment via a C-terminal glycosylphosphatidylinositol anchor is critical for conversion of PrP(C) into pathogenic PrP(Sc). Therefore the effects of the anchor on PrP structure and function need to be deciphered. Three PrP variants, including full-length PrP (residues 23-231, FL_PrP), N-terminally truncated PrP (residues 90-231, T_PrP), and PrP missing its central hydrophobic region (Δ105-125, ΔCR_PrP), were equipped with a C-terminal membrane anchor via a semisynthesis strategy. Analyses of the interactions of lipidated PrPs with phospholipid membranes demonstrated that C-terminal membrane attachment induces a different binding mode of PrP to membranes, distinct from that of non-lipidated PrPs, and influences the biochemical and conformational properties of PrPs. Additionally, fluorescence-based assays indicated pore formation by lipidated ΔCR_PrP, a variant that is known to be highly neurotoxic in transgenic mice. This finding was supported by using patch clamp electrophysiological measurements of cultured cells. These results provide new evidence for the role of the membrane anchor in PrP-lipid interactions, highlighting the importance of the N-terminal and the central hydrophobic domain in these interactions.
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Affiliation(s)
- Nam K Chu
- From the Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, Währinger Strasse 38, 1090 Vienna, Austria
| | - Waheed Shabbir
- the Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria, and
| | - Erin Bove-Fenderson
- the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Can Araman
- From the Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, Währinger Strasse 38, 1090 Vienna, Austria
| | - Rosa Lemmens-Gruber
- the Department of Pharmacology and Toxicology, University of Vienna, Althanstrasse 14, 1090 Vienna, Austria, and
| | - David A Harris
- the Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Christian F W Becker
- From the Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, Währinger Strasse 38, 1090 Vienna, Austria,
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16
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Kaya AI, Lokits AD, Gilbert JA, Iverson TM, Meiler J, Hamm HE. A conserved phenylalanine as a relay between the α5 helix and the GDP binding region of heterotrimeric Gi protein α subunit. J Biol Chem 2014; 289:24475-87. [PMID: 25037222 PMCID: PMC4148873 DOI: 10.1074/jbc.m114.572875] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Revised: 07/15/2014] [Indexed: 11/06/2022] Open
Abstract
G protein activation by G protein-coupled receptors is one of the critical steps for many cellular signal transduction pathways. Previously, we and other groups reported that the α5 helix in the G protein α subunit plays a major role during this activation process. However, the precise signaling pathway between the α5 helix and the guanosine diphosphate (GDP) binding pocket remains elusive. Here, using structural, biochemical, and computational techniques, we probed different residues around the α5 helix for their role in signaling. Our data showed that perturbing the Phe-336 residue disturbs hydrophobic interactions with the β2-β3 strands and α1 helix, leading to high basal nucleotide exchange. However, mutations in β strands β5 and β6 do not perturb G protein activation. We have highlighted critical residues that leverage Phe-336 as a relay. Conformational changes are transmitted starting from Phe-336 via β2-β3/α1 to Switch I and the phosphate binding loop, decreasing the stability of the GDP binding pocket and triggering nucleotide release. When the α1 and α5 helices were cross-linked, inhibiting the receptor-mediated displacement of the C-terminal α5 helix, mutation of Phe-336 still leads to high basal exchange rates. This suggests that unlike receptor-mediated activation, helix 5 rotation and translocation are not necessary for GDP release from the α subunit. Rather, destabilization of the backdoor region of the Gα subunit is sufficient for triggering the activation process.
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Affiliation(s)
| | | | | | | | - Jens Meiler
- From the Departments of Pharmacology, Chemistry, Vanderbilt University Medical Center, Nashville, Tennessee 37232
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17
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Kacprzyk-Stokowiec A, Kulma M, Traczyk G, Kwiatkowska K, Sobota A, Dadlez M. Crucial role of perfringolysin O D1 domain in orchestrating structural transitions leading to membrane-perforating pores: a hydrogen-deuterium exchange study. J Biol Chem 2014; 289:28738-52. [PMID: 25164812 DOI: 10.1074/jbc.m114.577981] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Perfringolysin O (PFO) is a toxic protein that binds to cholesterol-containing membranes, oligomerizes, and forms a β-barrel transmembrane pore, leading to cell lysis. Previous studies have uncovered the sequence of events in this multistage structural transition to a considerable detail, but the underlying molecular mechanisms are not yet fully understood. By measuring hydrogen-deuterium exchange patterns of peptide bond amide protons monitored by mass spectrometry (MS), we have mapped structural changes in PFO and its variant bearing a point mutation during incorporation to the lipid environment. We have defined all regions that undergo structural changes caused by the interaction with the lipid environment both in wild-type PFO, thus providing new experimental constraints for molecular modeling of the pore formation process, and in a point mutant, W165T, for which the pore formation process is known to be inefficient. We have demonstrated that point mutation W165T causes destabilization of protein solution structure, strongest for domain D1, which interrupts the pathway of structural transitions in other domains necessary for proper oligomerization in the membrane. In PFO, the strongest changes accompanying binding to the membrane focus in D1; the C-terminal part of D4; and strands β1, β4, and β5 of D3. These changes were much weaker for PFO(W165T) lipo where substantial stabilization was observed only in D4 domain. In this study, the application of hydrogen-deuterium exchange analysis monitored by MS provided new insight into conformational changes of PFO associated with the membrane binding, oligomerization, and lytic pore formation.
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Affiliation(s)
- Aleksandra Kacprzyk-Stokowiec
- From the Department of Biophysics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 5A Pawinskiego St., 02-106 Warsaw, Poland
| | - Magdalena Kulma
- From the Department of Biophysics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 5A Pawinskiego St., 02-106 Warsaw, Poland
| | - Gabriela Traczyk
- Department of Cell Biology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St., 02-093 Warsaw, Poland, and
| | - Katarzyna Kwiatkowska
- Department of Cell Biology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St., 02-093 Warsaw, Poland, and
| | - Andrzej Sobota
- Department of Cell Biology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur St., 02-093 Warsaw, Poland, and
| | - Michał Dadlez
- From the Department of Biophysics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, 5A Pawinskiego St., 02-106 Warsaw, Poland, Department of Biology, Institute of Genetics and Biotechnology, Warsaw University, 1 Miecznikowa Street, 02-185 Warsaw, Poland
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18
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Zhang Z, Wu J, Lin W, Wang J, Yan H, Zhao W, Ma J, Ding J, Zhang P, Zhao GP. Subdomain II of α-isopropylmalate synthase is essential for activity: inferring a mechanism of feedback inhibition. J Biol Chem 2014; 289:27966-78. [PMID: 25128527 DOI: 10.1074/jbc.m114.559716] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The committed step of leucine biosynthesis, converting acetyl-CoA and α-ketoisovalerate into α-isopropylmalate, is catalyzed by α-isopropylmalate synthase (IPMS), an allosteric enzyme subjected to feedback inhibition by the end product L-leucine. We characterized the short form IPMS from Leptospira biflexa (LbIPMS2), which exhibits a catalytic activity comparable with that of the long form IPMS (LbIPMS1) and has a similar N-terminal domain followed by subdomain I and subdomain II but lacks the whole C-terminal regulatory domain. We found that partial deletion of the regulatory domain of LbIPMS1 resulted in a loss of about 50% of the catalytic activity; however, when the regulatory domain was deleted up to Arg-385, producing a protein that is almost equivalent to the intact LbIPMS2, about 90% of the activity was maintained. Moreover, in LbIPMS2 or LbIPMS1, further deletion of several residues from the C terminus of subdomain II significantly impaired or completely abolished the catalytic activity, respectively. These results define a complete and independently functional catalytic module of IPMS consisting of both the N-terminal domain and the two subdomains. Structural comparison of LbIPMS2 and the Mycobacterium tuberculosis IPMS revealed two different conformations of subdomain II that likely represent two substrate-binding states related to cooperative catalysis. The biochemical and structural analyses together with the previously published hydrogen-deuterium exchange data led us to propose a conformation transition mechanism for feedback inhibition mediated by subdomains I and II that might associated with alteration of the binding affinity toward acetyl-CoA.
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Affiliation(s)
- Zilong Zhang
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology and Shanghai International Travel Healthcare Center, Shanghai Entry-Exit Inspection and Quarantine Bureau, Shanghai 200335, China
| | - Jian Wu
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Wei Lin
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology and
| | - Jin Wang
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology and
| | - Han Yan
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology and
| | - Wei Zhao
- Key Laboratory of Medical Molecular Virology affiliated to the Ministries of Education and Health, Shanghai Medical College, and Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Jun Ma
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology and
| | - Jianping Ding
- State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China,
| | - Peng Zhang
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology and National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China,
| | - Guo-Ping Zhao
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology and Key Laboratory of Medical Molecular Virology affiliated to the Ministries of Education and Health, Shanghai Medical College, and Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200433, China, Shanghai-Ministry of Science and Technology Key Laboratory for Health and Disease Genomics, Chinese National Human Genome Center, Shanghai 201203, China, Department of Microbiology and Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong Special Administrative Region 999077, China, and
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19
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Okumura M, Kadokura H, Hashimoto S, Yutani K, Kanemura S, Hikima T, Hidaka Y, Ito L, Shiba K, Masui S, Imai D, Imaoka S, Yamaguchi H, Inaba K. Inhibition of the functional interplay between endoplasmic reticulum (ER) oxidoreduclin-1α (Ero1α) and protein-disulfide isomerase (PDI) by the endocrine disruptor bisphenol A. J Biol Chem 2014; 289:27004-27018. [PMID: 25122773 PMCID: PMC4175339 DOI: 10.1074/jbc.m114.564104] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Bisphenol A (BPA) is an endocrine disruptor that may have adverse effects on human health. We recently isolated protein-disulfide isomerase (PDI) as a BPA-binding protein from rat brain homogenates and found that BPA markedly inhibited PDI activity. To elucidate mechanisms of this inhibition, detailed structural, biophysical, and functional analyses of PDI were performed in the presence of BPA. BPA binding to PDI induced significant rearrangement of the N-terminal thioredoxin domain of PDI, resulting in more compact overall structure. This conformational change led to closure of the substrate-binding pocket in b' domain, preventing PDI from binding to unfolded proteins. The b' domain also plays an essential role in the interplay between PDI and ER oxidoreduclin 1α (Ero1α), a flavoenzyme responsible for reoxidation of PDI. We show that BPA inhibited Ero1α-catalyzed PDI oxidation presumably by inhibiting the interaction between the b' domain of PDI and Ero1α; the phenol groups of BPA probably compete with a highly conserved tryptophan residue, located in the protruding β-hairpin of Ero1α, for binding to PDI. Consistently, BPA slowed down the reoxidation of PDI and caused the reduction of PDI in HeLa cells, indicating that BPA has a great impact on the redox homeostasis of PDI within cells. However, BPA had no effect on the interaction between PDI and peroxiredoxin-4 (Prx4), another PDI family oxidase, suggesting that the interaction between Prx4 and PDI is different from that of Ero1α and PDI. These results indicate that BPA, a widely distributed and potentially harmful chemical, inhibits Ero1-PDI-mediated disulfide bond formation.
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Affiliation(s)
- Masaki Okumura
- School of Science and Technology, Kwansei Gakuin University, Gakuen 2-1, Sanda, Hyogo 669-1337, Japan,; Division of Protein Chemistry, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan,; RIKEN SPring-8 Center, RIKEN, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan,; School Faculty of Science and Engineering, Kinki University, Kowakae 3-4-1, Higashi-Osaka, Osaka 577-8502, Japan,; Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.
| | - Hiroshi Kadokura
- Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Shoko Hashimoto
- School of Science and Technology, Kwansei Gakuin University, Gakuen 2-1, Sanda, Hyogo 669-1337, Japan
| | - Katsuhide Yutani
- RIKEN SPring-8 Center, RIKEN, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Shingo Kanemura
- School of Science and Technology, Kwansei Gakuin University, Gakuen 2-1, Sanda, Hyogo 669-1337, Japan,; RIKEN SPring-8 Center, RIKEN, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan,; Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Takaaki Hikima
- RIKEN SPring-8 Center, RIKEN, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Yuji Hidaka
- School Faculty of Science and Engineering, Kinki University, Kowakae 3-4-1, Higashi-Osaka, Osaka 577-8502, Japan
| | - Len Ito
- School of Science and Technology, Kwansei Gakuin University, Gakuen 2-1, Sanda, Hyogo 669-1337, Japan
| | - Kohei Shiba
- ProCube Business Division, Sysmex Corporation, 1-1-2, Murotani, Nishi-ku, Kobe, Hyogo, 651-2241, Japan, and
| | - Shoji Masui
- Division of Protein Chemistry, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan,; Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan
| | - Daiki Imai
- School of Science and Technology, Kwansei Gakuin University, Gakuen 2-1, Sanda, Hyogo 669-1337, Japan,; RIKEN SPring-8 Center, RIKEN, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan
| | - Susumu Imaoka
- School of Science and Technology, Kwansei Gakuin University, Gakuen 2-1, Sanda, Hyogo 669-1337, Japan
| | - Hiroshi Yamaguchi
- School of Science and Technology, Kwansei Gakuin University, Gakuen 2-1, Sanda, Hyogo 669-1337, Japan,; RIKEN SPring-8 Center, RIKEN, 1-1-1 Kouto, Sayo-cho, Sayo-gun, Hyogo 679-5148, Japan,.
| | - Kenji Inaba
- Division of Protein Chemistry, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka 812-8582, Japan,; Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Katahira 2-1-1, Aoba-ku, Sendai 980-8577, Japan.
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20
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Krejciova Z, Barria MA, Jones M, Ironside JW, Jeffrey M, González L, Head MW. Genotype-dependent molecular evolution of sheep bovine spongiform encephalopathy (BSE) prions in vitro affects their zoonotic potential. J Biol Chem 2014; 289:26075-26088. [PMID: 25100723 DOI: 10.1074/jbc.m114.582965] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Prion diseases are rare fatal neurological conditions of humans and animals, one of which (variant Creutzfeldt-Jakob disease) is known to be a zoonotic form of the cattle disease bovine spongiform encephalopathy (BSE). What makes one animal prion disease zoonotic and others not is poorly understood, but it appears to involve compatibility between the prion strain and the host prion protein sequence. Concerns have been raised that the United Kingdom sheep flock may have been exposed to BSE early in the cattle BSE epidemic and that serial BSE transmission in sheep might have resulted in adaptation of the agent, which may have come to phenotypically resemble scrapie while maintaining its pathogenicity for humans. We have modeled this scenario in vitro. Extrapolation from our results suggests that if BSE were to infect sheep in the field it may, with time and in some sheep genotypes, become scrapie-like at the molecular level. However, the results also suggest that if BSE in sheep were to come to resemble scrapie it would lose its ability to affect humans.
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Affiliation(s)
- Zuzana Krejciova
- National Creutzfeldt-Jakob Disease Research and Surveillance Unit, The University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Marcelo A Barria
- National Creutzfeldt-Jakob Disease Research and Surveillance Unit, The University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Michael Jones
- Scottish National Blood Transfusion Service, Edinburgh EH17 7QT, United Kingdom, and
| | - James W Ironside
- National Creutzfeldt-Jakob Disease Research and Surveillance Unit, The University of Edinburgh, Edinburgh EH4 2XU, United Kingdom
| | - Martin Jeffrey
- Animal Health and Veterinary Laboratories Agency, Lasswade, Edinburgh EH26 0PZ, United Kingdom
| | - Lorenzo González
- Animal Health and Veterinary Laboratories Agency, Lasswade, Edinburgh EH26 0PZ, United Kingdom
| | - Mark W Head
- National Creutzfeldt-Jakob Disease Research and Surveillance Unit, The University of Edinburgh, Edinburgh EH4 2XU, United Kingdom,.
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21
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Qin X, Hao Z, Tian Q, Zhang Z, Zhou C, Xie W. Cocrystal structures of glycyl-tRNA synthetase in complex with tRNA suggest multiple conformational states in glycylation. J Biol Chem 2014; 289:20359-69. [PMID: 24898252 PMCID: PMC4106348 DOI: 10.1074/jbc.m114.557249] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 05/31/2014] [Indexed: 12/16/2022] Open
Abstract
Aminoacyl-tRNA synthetases are an ancient enzyme family that specifically charges tRNA molecules with cognate amino acids for protein synthesis. Glycyl-tRNA synthetase (GlyRS) is one of the most intriguing aminoacyl-tRNA synthetases due to its divergent quaternary structure and abnormal charging properties. In the past decade, mutations of human GlyRS (hGlyRS) were also found to be associated with Charcot-Marie-Tooth disease. However, the mechanisms of traditional and alternative functions of hGlyRS are poorly understood due to a lack of studies at the molecular basis. In this study we report crystal structures of wild type and mutant hGlyRS in complex with tRNA and with small substrates and describe the molecular details of enzymatic recognition of the key tRNA identity elements in the acceptor stem and the anticodon loop. The cocrystal structures suggest that insertions 1 and 3 work together with the active site in a cooperative manner to facilitate efficient substrate binding. Both the enzyme and tRNA molecules undergo significant conformational changes during glycylation. A working model of multiple conformations for hGlyRS catalysis is proposed based on the crystallographic and biochemical studies. This study provides insights into the catalytic pathway of hGlyRS and may also contribute to our understanding of Charcot-Marie-Tooth disease.
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Affiliation(s)
- Xiangjing Qin
- From the Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou 510275, China, Center for Cellular and Structural Biology, The Sun Yat-Sen University, 132 E. Circle, University City, Guangzhou 510006, China, and
| | - Zhitai Hao
- From the Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou 510275, China, Center for Cellular and Structural Biology, The Sun Yat-Sen University, 132 E. Circle, University City, Guangzhou 510006, China, and
| | - Qingnan Tian
- From the Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou 510275, China, Center for Cellular and Structural Biology, The Sun Yat-Sen University, 132 E. Circle, University City, Guangzhou 510006, China, and
| | - Zhemin Zhang
- From the Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou 510275, China, Center for Cellular and Structural Biology, The Sun Yat-Sen University, 132 E. Circle, University City, Guangzhou 510006, China, and
| | - Chun Zhou
- Structural Biology Program, Memorial Sloan-Kettering Cancer Center, New York, New York 10065
| | - Wei Xie
- From the Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, School of Life Sciences, The Sun Yat-Sen University, Guangzhou 510275, China, Center for Cellular and Structural Biology, The Sun Yat-Sen University, 132 E. Circle, University City, Guangzhou 510006, China, and
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22
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Howes JM, Bihan D, Slatter DA, Hamaia SW, Packman LC, Knauper V, Visse R, Farndale RW. The recognition of collagen and triple-helical toolkit peptides by MMP-13: sequence specificity for binding and cleavage. J Biol Chem 2014; 289:24091-101. [PMID: 25008319 PMCID: PMC4148842 DOI: 10.1074/jbc.m114.583443] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Remodeling of collagen by matrix metalloproteinases (MMPs) is crucial to tissue homeostasis and repair. MMP-13 is a collagenase with a substrate preference for collagen II over collagens I and III. It recognizes a specific, well-known site in the tropocollagen molecule where its binding locally perturbs the triple helix, allowing the catalytic domain of the active enzyme to cleave the collagen α chains sequentially, at Gly775–Leu776 in collagen II. However, the specific residues upon which collagen recognition depends within and surrounding this locus have not been systematically mapped. Using our triple-helical peptide Collagen Toolkit libraries in solid-phase binding assays, we found that MMP-13 shows little affinity for Collagen Toolkit III, but binds selectively to two triple-helical peptides of Toolkit II. We have identified the residues required for the adhesion of both proMMP-13 and MMP-13 to one of these, Toolkit peptide II-44, which contains the canonical collagenase cleavage site. MMP-13 was unable to bind to a linear peptide of the same sequence as II-44. We also discovered a second binding site near the N terminus of collagen II (starting at helix residue 127) in Toolkit peptide II-8. The pattern of binding of the free hemopexin domain of MMP-13 was similar to that of the full-length enzyme, but the free catalytic subunit bound none of our peptides. The susceptibility of Toolkit peptides to proteolysis in solution was independent of the very specific recognition of immobilized peptides by MMP-13; the enzyme proved able to cleave a range of dissolved collagen peptides.
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Affiliation(s)
- Joanna-Marie Howes
- From the Department of Biochemistry, University of Cambridge, Downing Site, Cambridge CB2 1QW, United Kingdom
| | - Dominique Bihan
- From the Department of Biochemistry, University of Cambridge, Downing Site, Cambridge CB2 1QW, United Kingdom
| | - David A Slatter
- From the Department of Biochemistry, University of Cambridge, Downing Site, Cambridge CB2 1QW, United Kingdom
| | - Samir W Hamaia
- From the Department of Biochemistry, University of Cambridge, Downing Site, Cambridge CB2 1QW, United Kingdom
| | - Len C Packman
- From the Department of Biochemistry, University of Cambridge, Downing Site, Cambridge CB2 1QW, United Kingdom
| | - Vera Knauper
- the Cardiff University Dental School, Dental Drive, Cardiff CF14 4XY, United Kingdom, and
| | - Robert Visse
- the Kennedy Institute of Rheumatology, Hammersmith, London W6 8LH, United Kingdom
| | - Richard W Farndale
- From the Department of Biochemistry, University of Cambridge, Downing Site, Cambridge CB2 1QW, United Kingdom,
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23
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Weber M, Hartmann AM, Beyer T, Ripperger A, Nothwang HG. A novel regulatory locus of phosphorylation in the C terminus of the potassium chloride cotransporter KCC2 that interferes with N-ethylmaleimide or staurosporine-mediated activation. J Biol Chem 2014; 289:18668-79. [PMID: 24849604 PMCID: PMC4081912 DOI: 10.1074/jbc.m114.567834] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 05/15/2014] [Indexed: 11/06/2022] Open
Abstract
The neuron-specific cation chloride cotransporter KCC2 plays a crucial role in hyperpolarizing synaptic inhibition. Transporter dysfunction is associated with various neurological disorders, raising interest in regulatory mechanisms. Phosphorylation has been identified as a key regulatory process. Here, we retrieved experimentally observed phosphorylation sites of KCC2 from public databases and report on the systematic analysis of six phosphorylated serines, Ser(25), Ser(26), Ser(937), Ser(1022), Ser(1025), and Ser(1026). Alanine or aspartate substitutions of these residues were analyzed in HEK-293 cells. All mutants were expressed in a pattern similar to wild-type KCC2 (KCC2(WT)). Tl(+) flux measurements demonstrated unchanged transport activity for Ser(25), Ser(26), Ser(1022), Ser(1025), and Ser(1026) mutants. In contrast, KCC2(S937D), mimicking phosphorylation, resulted in a significant up-regulation of transport activity. Aspartate substitution of Thr(934), a neighboring putative phosphorylation site, resulted in a comparable increase in KCC2 transport activity. Both KCC2(T934D) and KCC2(S937D) mutants were inhibited by the kinase inhibitor staurosporine and by N-ethylmaleimide, whereas KCC2(WT), KCC2(T934A), and KCC2(S937A) were activated. The inverse staurosporine effect on aspartate versus alanine substitutions reveals a cross-talk between different phosphorylation sites of KCC2. Immunoblot and cell surface labeling experiments detected no alterations in total abundance or surface expression of KCC2(T934D) and KCC2(S937D) compared with KCC2(WT). These data reveal kinetic regulation of transport activity by these residues. In summary, our data identify a novel key regulatory phosphorylation site of KCC2 and a functional interaction between different conformation-changing post-translational modifications. The action of pharmacological agents aimed to modulate KCC2 activity for therapeutic benefit might therefore be highly context-specific.
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Affiliation(s)
- Maren Weber
- From the Neurogenetics Group, Center of Excellence Hearing4All, School of Medicine and Health Sciences
| | - Anna-Maria Hartmann
- From the Neurogenetics Group, Center of Excellence Hearing4All, School of Medicine and Health Sciences, Systematics and Evolutionary Biology Group, Institute for Biology and Environmental Sciences, and
| | - Timo Beyer
- From the Neurogenetics Group, Center of Excellence Hearing4All, School of Medicine and Health Sciences
| | - Anne Ripperger
- From the Neurogenetics Group, Center of Excellence Hearing4All, School of Medicine and Health Sciences
| | - Hans Gerd Nothwang
- From the Neurogenetics Group, Center of Excellence Hearing4All, School of Medicine and Health Sciences, the Research Center for Neurosensory Sciences, Carl von Ossietzky University Oldenburg, 26111 Oldenburg, Germany
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24
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Kota P, Buchner G, Chakraborty H, Dang YL, He H, Garcia GJM, Kubelka J, Gentzsch M, Stutts MJ, Dokholyan NV. The N-terminal domain allosterically regulates cleavage and activation of the epithelial sodium channel. J Biol Chem 2014; 289:23029-23042. [PMID: 24973914 DOI: 10.1074/jbc.m114.570952] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The epithelial sodium channel (ENaC) is activated upon endoproteolytic cleavage of specific segments in the extracellular domains of the α- and γ-subunits. Cleavage is accomplished by intracellular proteases prior to membrane insertion and by surface-expressed or extracellular soluble proteases once ENaC resides at the cell surface. These cleavage events are partially regulated by intracellular signaling through an unknown allosteric mechanism. Here, using a combination of computational and experimental techniques, we show that the intracellular N terminus of γ-ENaC undergoes secondary structural transitions upon interaction with phosphoinositides. From ab initio folding simulations of the N termini in the presence and absence of phosphatidylinositol 4,5-bisphosphate (PIP2), we found that PIP2 increases α-helical propensity in the N terminus of γ-ENaC. Electrophysiology and mutation experiments revealed that a highly conserved cluster of lysines in the γ-ENaC N terminus regulates accessibility of extracellular cleavage sites in γ-ENaC. We also show that conditions that decrease PIP2 or enhance ubiquitination sharply limit access of the γ-ENaC extracellular domain to proteases. Further, the efficiency of allosteric control of ENaC proteolysis is dependent on Tyr(370) in γ-ENaC. Our findings provide an allosteric mechanism for ENaC activation regulated by the N termini and sheds light on a potential general mechanism of channel and receptor activation.
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Affiliation(s)
- Pradeep Kota
- Departments of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599; Departments of Molecular and Cellular Biophysics, and University of North Carolina, Chapel Hill, North Carolina 27599
| | - Ginka Buchner
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, and
| | - Hirak Chakraborty
- Departments of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Yan L Dang
- Departments of Cystic Fibrosis and Pulmonary Diseases Research and Treatment Center, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Hong He
- Departments of Cystic Fibrosis and Pulmonary Diseases Research and Treatment Center, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Guilherme J M Garcia
- Biotechnology & Bioengineering Center, Department of Otolaryngology and Communication Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin 53226
| | - Jan Kubelka
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, and
| | - Martina Gentzsch
- Departments of Cystic Fibrosis and Pulmonary Diseases Research and Treatment Center, University of North Carolina, Chapel Hill, North Carolina 27599,; Departments of Cell Biology and Physiology and University of North Carolina, Chapel Hill, North Carolina 27599
| | - M Jackson Stutts
- Departments of Cystic Fibrosis and Pulmonary Diseases Research and Treatment Center, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Nikolay V Dokholyan
- Departments of Biochemistry and Biophysics, University of North Carolina, Chapel Hill, North Carolina 27599; Departments of Molecular and Cellular Biophysics, and University of North Carolina, Chapel Hill, North Carolina 27599; Departments of Cystic Fibrosis and Pulmonary Diseases Research and Treatment Center, University of North Carolina, Chapel Hill, North Carolina 27599,.
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25
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Grüning CSR, Mirecka EA, Klein AN, Mandelkow E, Willbold D, Marino SF, Stoldt M, Hoyer W. Alternative conformations of the Tau repeat domain in complex with an engineered binding protein. J Biol Chem 2014; 289:23209-23218. [PMID: 24966331 DOI: 10.1074/jbc.m114.560920] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The aggregation of Tau into paired helical filaments is involved in the pathogenesis of several neurodegenerative diseases, including Alzheimer disease. The aggregation reaction is characterized by conformational conversion of the repeat domain, which partially adopts a cross-β-structure in the resulting amyloid-like fibrils. Here, we report the selection and characterization of an engineered binding protein, β-wrapin TP4, targeting the Tau repeat domain. TP4 was obtained by phage display using the four-repeat Tau construct K18ΔK280 as a target. TP4 binds K18ΔK280 as well as the longest isoform of human Tau, hTau40, with nanomolar affinity. NMR spectroscopy identified two alternative TP4-binding sites in the four-repeat domain, with each including two hexapeptide motifs with high β-sheet propensity. Both binding sites contain the aggregation-determining PHF6 hexapeptide within repeat 3. In addition, one binding site includes the PHF6* hexapeptide within repeat 2, whereas the other includes the corresponding hexapeptide Tau(337-342) within repeat 4, denoted PHF6**. Comparison of TP4-binding with Tau aggregation reveals that the same regions of Tau are involved in both processes. TP4 inhibits Tau aggregation at substoichiometric concentration, demonstrating that it interferes with aggregation nucleation. This study provides residue-level insight into the interaction of Tau with an aggregation inhibitor and highlights the structural flexibility of Tau.
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Affiliation(s)
- Clara S R Grüning
- Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany
| | - Ewa A Mirecka
- Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany
| | - Antonia N Klein
- Institute of Structural Biochemistry (ICS-6), Research Centre Jülich, 52425 Jülich, Germany
| | - Eckhard Mandelkow
- German Center for Neurodegenerative Diseases (DZNE), 53175 Bonn, Germany, and; Center of Advanced European Studies And Research (CAESAR), 53175 Bonn, Germany
| | - Dieter Willbold
- Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany,; Institute of Structural Biochemistry (ICS-6), Research Centre Jülich, 52425 Jülich, Germany
| | - Stephen F Marino
- Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany
| | - Matthias Stoldt
- Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany,; Institute of Structural Biochemistry (ICS-6), Research Centre Jülich, 52425 Jülich, Germany
| | - Wolfgang Hoyer
- Institute of Physical Biology, Heinrich-Heine-Universität, 40204 Düsseldorf, Germany,; Institute of Structural Biochemistry (ICS-6), Research Centre Jülich, 52425 Jülich, Germany,.
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26
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Harris G, Ma W, Maurer LM, Potts JR, Mosher DF. Borrelia burgdorferi protein BBK32 binds to soluble fibronectin via the N-terminal 70-kDa region, causing fibronectin to undergo conformational extension. J Biol Chem 2014; 289:22490-9. [PMID: 24962582 DOI: 10.1074/jbc.m114.578419] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
BBK32 is a fibronectin (FN)-binding protein expressed on the cell surface of Borrelia burgdorferi, the causative agent of Lyme disease. There is conflicting information about where and how BBK32 interacts with FN. We have characterized interactions of a recombinant 86-mer polypeptide, "Bbk32," comprising the unstructured FN-binding region of BBK32. Competitive enzyme-linked assays utilizing various FN fragments and epitope-mapped anti-FN monoclonal antibodies showed that Bbk32 binding involves both the fibrin-binding and the gelatin-binding domains of the 70-kDa N-terminal region (FN70K). Crystallographic and NMR analyses of smaller Bbk32 peptides complexed, respectively, with (2-3)FNI and (8-9)FNI, demonstrated that binding occurs by β-strand addition. Isothermal titration calorimetry indicated that Bbk32 binds to isolated FN70K more tightly than to intact FN. In a competitive enzyme-linked binding assay, complex formation with Bbk32 enhanced binding of FN with mAbIII-10 to the (10)FNIII module. Thus, Bbk32 binds to multiple FN type 1 modules of the FN70K region by a tandem β-zipper mechanism, and in doing so increases accessibility of FNIII modules that interact with other ligands. The similarity in the FN-binding mechanism of BBK32 and previously studied streptococcal proteins suggests that the binding and associated conformational change of FN play a role in infection.
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Affiliation(s)
- Gemma Harris
- From the Department of Biology, University of York, York YO10 5DD, United Kingdom and
| | - Wenjiang Ma
- the Departments of Biomolecular Chemistry and Medicine, University of Wisconsin, Madison, Wisconsin 53706
| | - Lisa M Maurer
- the Departments of Biomolecular Chemistry and Medicine, University of Wisconsin, Madison, Wisconsin 53706
| | - Jennifer R Potts
- From the Department of Biology, University of York, York YO10 5DD, United Kingdom and
| | - Deane F Mosher
- the Departments of Biomolecular Chemistry and Medicine, University of Wisconsin, Madison, Wisconsin 53706
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27
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Akimoto M, Zhang Z, Boulton S, Selvaratnam R, VanSchouwen B, Gloyd M, Accili EA, Lange OF, Melacini G. A mechanism for the auto-inhibition of hyperpolarization-activated cyclic nucleotide-gated (HCN) channel opening and its relief by cAMP. J Biol Chem 2014; 289:22205-20. [PMID: 24878962 DOI: 10.1074/jbc.m114.572164] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN) ion channels control neuronal and cardiac electrical rhythmicity. There are four homologous isoforms (HCN1-4) sharing a common multidomain architecture that includes an N-terminal transmembrane tetrameric ion channel followed by a cytoplasmic "C-linker," which connects a more distal cAMP-binding domain (CBD) to the inner pore. Channel opening is primarily stimulated by transmembrane elements that sense membrane hyperpolarization, although cAMP reduces the voltage required for HCN activation by promoting tetramerization of the intracellular C-linker, which in turn relieves auto-inhibition of the inner pore gate. Although binding of cAMP has been proposed to relieve auto-inhibition by affecting the structure of the C-linker and CBD, the nature and extent of these cAMP-dependent changes remain limitedly explored. Here, we used NMR to probe the changes caused by the binding of cAMP and of cCMP, a partial agonist, to the apo-CBD of HCN4. Our data indicate that the CBD exists in a dynamic two-state equilibrium, whose position as gauged by NMR chemical shifts correlates with the V½ voltage measured through electrophysiology. In the absence of cAMP, the most populated CBD state leads to steric clashes with the activated or "tetrameric" C-linker, which becomes energetically unfavored. The steric clashes of the apo tetramer are eliminated either by cAMP binding, which selects for a CBD state devoid of steric clashes with the tetrameric C-linker and facilitates channel opening, or by a transition of apo-HCN to monomers or dimer of dimers, in which the C-linker becomes less structured, and channel opening is not facilitated.
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Affiliation(s)
- Madoka Akimoto
- From the Departments of Chemistry and Chemical Biology and
| | - Zaiyong Zhang
- the Biomolecular NMR and Munich Center for Integrated Protein Science, Department of Chemie, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany
| | - Stephen Boulton
- Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | | | | | - Melanie Gloyd
- From the Departments of Chemistry and Chemical Biology and Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Eric A Accili
- the Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada, and
| | - Oliver F Lange
- the Biomolecular NMR and Munich Center for Integrated Protein Science, Department of Chemie, Technische Universität München, Lichtenbergstrasse 4, 85747 Garching, Germany, the Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Giuseppe Melacini
- From the Departments of Chemistry and Chemical Biology and Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4M1, Canada,
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Towle-Weicksel JB, Dalal S, Sohl CD, Doublié S, Anderson KS, Sweasy JB. Fluorescence resonance energy transfer studies of DNA polymerase β: the critical role of fingers domain movements and a novel non-covalent step during nucleotide selection. J Biol Chem 2014; 289:16541-50. [PMID: 24764311 DOI: 10.1074/jbc.m114.561878] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During DNA repair, DNA polymerase β (Pol β) is a highly dynamic enzyme that is able to select the correct nucleotide opposite a templating base from a pool of four different deoxynucleoside triphosphates (dNTPs). To gain insight into nucleotide selection, we use a fluorescence resonance energy transfer (FRET)-based system to monitor movement of the Pol β fingers domain during catalysis in the presence of either correct or incorrect dNTPs. By labeling the fingers domain with ((((2-iodoacetyl)amino)ethyl)amino)naphthalene-1-sulfonic acid (IAEDANS) and the DNA substrate with Dabcyl, we are able to observe rapid fingers closing in the presence of correct dNTPs as the IAEDANS comes into contact with a Dabcyl-labeled, one-base gapped DNA. Our findings show that not only do the fingers close after binding to the correct dNTP, but that there is a second conformational change associated with a non-covalent step not previously reported for Pol β. Further analyses suggest that this conformational change corresponds to the binding of the catalytic metal into the polymerase active site. FRET studies with incorrect dNTP result in no changes in fluorescence, indicating that the fingers do not close in the presence of incorrect dNTP. Together, our results show that nucleotide selection initially occurs in an open fingers conformation and that the catalytic pathways of correct and incorrect dNTPs differ from each other. Overall, this study provides new insight into the mechanism of substrate choice by a polymerase that plays a critical role in maintaining genome stability.
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Affiliation(s)
| | | | - Christal D Sohl
- Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520 and
| | - Sylvie Doublié
- the Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont 05405
| | - Karen S Anderson
- Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520 and
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Sun Y, Yin S, Feng Y, Li J, Zhou J, Liu C, Zhu G, Guo Z. Molecular basis of the general base catalysis of an α/β-hydrolase catalytic triad. J Biol Chem 2014; 289:15867-79. [PMID: 24737327 DOI: 10.1074/jbc.m113.535641] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The serine-histidine-aspartate triad is well known for its covalent, nucleophilic catalysis in a diverse array of enzymatic transformations. Here we show that its nucleophilicity is shielded and its catalytic role is limited to being a specific general base by an open-closed conformational change in the catalysis of (1R,6R)-2-succinyl-6-hydroxy-2,4-cyclohexadiene-1-carboxylate synthase (or MenH), a typical α/β-hydrolase fold enzyme in the vitamin K biosynthetic pathway. This enzyme is found to adopt an open conformation without a functional triad in its ligand-free form and a closed conformation with a fully functional catalytic triad in the presence of its reaction product. The open-to-closed conformational transition involves movement of half of the α-helical cap domain, which causes extensive structural changes in the α/β-domain and forces the side chain of the triad histidine to adopt an energetically disfavored gauche conformation to form the functional triad. NMR analysis shows that the inactive open conformation without a triad prevails in ligand-free solution and is converted to the closed conformation with a properly formed triad by the reaction product. Mutation of the residues crucial to this open-closed transition either greatly decreases or completely eliminates the enzyme activity, supporting an important catalytic role for the structural change. These findings suggest that the open-closed conformational change tightly couples formation of the catalytic triad to substrate binding to enhance the substrate specificities and simultaneously shield the nucleophilicity of the triad, thus allowing it to expand its catalytic power beyond the nucleophilic catalysis.
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Affiliation(s)
- Yueru Sun
- From the Department of Chemistry, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Special Administrative Region (SAR), China and
| | - Shuhui Yin
- From the Department of Chemistry, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Special Administrative Region (SAR), China and
| | - Yitao Feng
- From the Department of Chemistry, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Special Administrative Region (SAR), China and
| | - Jie Li
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Jiahai Zhou
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai 200032, China
| | - Changdong Liu
- State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Special Administrative Region (SAR), China and Division of Life Sciences, and
| | - Guang Zhu
- State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Special Administrative Region (SAR), China and Division of Life Sciences, and
| | - Zhihong Guo
- From the Department of Chemistry, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong Special Administrative Region (SAR), China and
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Lin W, Wang Y, Han X, Zhang Z, Wang C, Wang J, Yang H, Lu Y, Jiang W, Zhao GP, Zhang P. Atypical OmpR/PhoB subfamily response regulator GlnR of actinomycetes functions as a homodimer, stabilized by the unphosphorylated conserved Asp-focused charge interactions. J Biol Chem 2014; 289:15413-25. [PMID: 24733389 DOI: 10.1074/jbc.m113.543504] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The OmpR/PhoB subfamily protein GlnR of actinomycetes is an orphan response regulator that globally coordinates the expression of genes related to nitrogen metabolism. Biochemical and genetic analyses reveal that the functional GlnR from Amycolatopsis mediterranei is unphosphorylated at the potential phosphorylation Asp(50) residue in the N-terminal receiver domain. The crystal structure of this receiver domain demonstrates that it forms a homodimer through the α4-β5-α5 dimer interface highly similar to the phosphorylated typical response regulator, whereas the so-called "phosphorylation pocket" is not conserved, with its space being occupied by an Arg(52) from the β3-α3 loop. Both in vitro and in vivo experiments confirm that GlnR forms a functional homodimer via its receiver domain and suggest that the charge interactions of Asp(50) with the highly conserved Arg(52) and Thr(9) in the receiver domain may be crucial in maintaining the proper conformation for homodimerization, as also supported by molecular dynamics simulations of the wild type GlnR versus the deficient mutant GlnR(D50A). This model is backed by the distinct phenotypes of the total deficient GlnR(R52A/T9A) double mutant versus the single mutants of GlnR (i.e. D50N, D50E, R52A and T9A), which have only minor effects upon both dimerization and physiological function of GlnR in vivo, albeit their DNA binding ability is weakened compared with that of the wild type. By integrating the supportive data of GlnRs from the model Streptomyces coelicolor and the pathogenic Mycobacterium tuberculosis, we conclude that the actinomycete GlnR is atypical with respect to its unphosphorylated conserved Asp residue being involved in the critical Arg/Asp/Thr charge interactions, which is essential for maintaining the biologically active homodimer conformation.
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Affiliation(s)
- Wei Lin
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology
| | - Ying Wang
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology, the State Key Laboratory of Genetic Engineering, Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Xiaobiao Han
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology
| | - Zilong Zhang
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology
| | - Chengyuan Wang
- State Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China
| | - Jin Wang
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology
| | - Huaiyu Yang
- the Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China
| | - Yinhua Lu
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology
| | - Weihong Jiang
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology
| | - Guo-Ping Zhao
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology, the State Key Laboratory of Genetic Engineering, Department of Microbiology and Microbial Engineering, School of Life Sciences, Fudan University, Shanghai 200433, China, the Shanghai-MOST Key Laboratory of Disease and Health Genomics, Chinese National Human Genome Center at Shanghai, Shanghai 201203, China, the Department of Microbiology and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Prince of Wales Hospital, Shatin, New Territories, Hong Kong SAR, China, and
| | - Peng Zhang
- From the Chinese Academy of Sciences Key Laboratory of Synthetic Biology, State Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200032, China,
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31
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Juneja P, Horlacher R, Bertrand D, Krause R, Marger F, Welte W. An internally modulated, thermostable, pH-sensitive Cys loop receptor from the hydrothermal vent worm Alvinella pompejana. J Biol Chem 2014; 289:15130-40. [PMID: 24719323 DOI: 10.1074/jbc.m113.525576] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Cys loop receptors (CLRs) are commonly known as ligand-gated channels that transiently open upon binding of neurotransmitters to modify the membrane potential. However, a class of cation-selective bacterial homologues of CLRs have been found to open upon a sudden pH drop, suggesting further ligands and more functions of the homologues in prokaryotes. Here we report an anion-selective CLR from the hydrothermal vent annelid worm Alvinella pompejana that opens at low pH. A. pompejana expressed sequence tag databases were explored by us, and two full-length CLR sequences were identified, synthesized, cloned, expressed in Xenopus oocytes, and studied by two-electrode voltage clamp. One channel, named Alv-a1-pHCl, yielded functional receptors and opened upon a sudden pH drop but not by other known agonists. Sequence comparison showed that both CLR proteins share conserved characteristics with eukaryotic CLRs, such as an N-terminal helix, a cysteine loop motif, and an intracellular loop intermediate in length between the long loops of other eukaryotic CLRs and those of prokaryotic CLRs. Both full-length Alv-a1-pHCl and a truncated form, termed tAlv-a1-pHCl, lacking 37 amino-terminal residues that precede the N-terminal helix, formed functional channels in oocytes. After pH activation, tAlv-a1-pHCl showed desensitization and was not modulated by ivermectin. In contrast, pH-activated, full-length Alv-a1-pHCl showed a marked rebound current and was modulated significantly by ivermectin. A thermostability assay indicated that purified tAlv-a1-pHCl expressed in Sf9 cells denatured at a higher temperature than the nicotinic acetylcholine receptor from Torpedo californica.
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Affiliation(s)
- Puneet Juneja
- From the Fachbereich Biologie, Universität Konstanz, Universitätsstraβe 10, 78457 Konstanz, Germany
| | | | - Daniel Bertrand
- HiQScreen Sàrl, 6, rte. de Compois, 1222 Vésenaz, Geneva, Switzerland
| | - Ryoko Krause
- HiQScreen Sàrl, 6, rte. de Compois, 1222 Vésenaz, Geneva, Switzerland
| | - Fabrice Marger
- HiQScreen Sàrl, 6, rte. de Compois, 1222 Vésenaz, Geneva, Switzerland
| | - Wolfram Welte
- From the Fachbereich Biologie, Universität Konstanz, Universitätsstraβe 10, 78457 Konstanz, Germany,
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32
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Yamazaki Y, Nagata T, Terakita A, Kandori H, Shichida Y, Imamoto Y. Intramolecular interactions that induce helical rearrangement upon rhodopsin activation: light-induced structural changes in metarhodopsin IIa probed by cysteine S-H stretching vibrations. J Biol Chem 2014; 289:13792-800. [PMID: 24692562 DOI: 10.1074/jbc.m113.527606] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Rhodopsin undergoes rearrangements of its transmembrane helices after photon absorption to transfer a light signal to the G-protein transducin. To investigate the mechanism by which rhodopsin adopts the transducin-activating conformation, the local environmental changes in the transmembrane region were probed using the cysteine S-H group, whose stretching frequency is well isolated from the other protein vibrational modes. The S-H stretching modes of cysteine residues introduced into Helix III, which contains several key residues for the helical movements, and of native cysteine residues were measured by Fourier transform infrared spectroscopy. This method was applied to metarhodopsin IIa, a precursor of the transducin-activating state in which the intramolecular interactions are likely to produce a state ready for helical movements. No environmental change was observed near the ionic lock between Arg-135 in Helix III and Glu-247 in Helix VI that maintains the inactive conformation. Rather, the cysteine residues that showed environmental changes were located around the chromophore, Ala-164, His-211, and Phe-261. These findings imply that the hydrogen bond between Helix III and Helix V involving Glu-122 and His-211 and the hydrophobic packing between Helix III and Helix VI involving Gly-121, Leu-125, Phe-261, and Trp-265 are altered before the helical rearrangement leading toward the active conformation.
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Affiliation(s)
- Yoichi Yamazaki
- From the Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan, the Graduate School of Materials Science, Nara Institute of Science and Technology, Nara, 630-0192, Japan
| | - Tomoko Nagata
- From the Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Akihisa Terakita
- From the Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan, the Department of Biology and Geosciences, Graduate School of Science, Osaka City University, Osaka 558-8585, Japan, and
| | - Hideki Kandori
- From the Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan, the Department of Frontier Materials, Graduate School of Engineering, Nagoya Institute of Technology, Nagoya 466-8555, Japan
| | - Yoshinori Shichida
- From the Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Yasushi Imamoto
- From the Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan,
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33
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Dixon AM, Drake L, Hughes KT, Sargent E, Hunt D, Harton JA, Drake JR. Differential transmembrane domain GXXXG motif pairing impacts major histocompatibility complex (MHC) class II structure. J Biol Chem 2014; 289:11695-11703. [PMID: 24619409 DOI: 10.1074/jbc.m113.516997] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Major histocompatibility complex (MHC) class II molecules exhibit conformational heterogeneity, which influences their ability to stimulate CD4 T cells and drive immune responses. Previous studies suggest a role for the transmembrane domain of the class II αβ heterodimer in determining molecular structure and function. Our previous studies identified an MHC class II conformer that is marked by the Ia.2 epitope. These Ia.2(+) class II conformers are lipid raft-associated and able to drive both tyrosine kinase signaling and efficient antigen presentation to CD4 T cells. Here, we establish that the Ia.2(+) I-A(k) conformer is formed early in the class II biosynthetic pathway and that differential pairing of highly conserved transmembrane domain GXXXG dimerization motifs is responsible for formation of Ia.2(+) versus Ia.2(-) I-A(k) class II conformers and controlling lipid raft partitioning. These findings provide a molecular explanation for the formation of two distinct MHC class II conformers that differ in their inherent ability to signal and drive robust T cell activation, providing new insight into the role of MHC class II in regulating antigen-presenting cell-T cell interactions critical to the initiation and control of multiple aspects of the immune response.
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Affiliation(s)
- Ann M Dixon
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Lisa Drake
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208
| | - Kelly T Hughes
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208
| | - Elizabeth Sargent
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208
| | - Danielle Hunt
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208
| | - Jonathan A Harton
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208
| | - James R Drake
- Center for Immunology and Microbial Disease, Albany Medical College, Albany, New York 12208.
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Schurek EM, Völker LA, Tax J, Lamkemeyer T, Rinschen MM, Ungrue D, Kratz JE, Sirianant L, Kunzelmann K, Chalfie M, Schermer B, Benzing T, Höhne M. A disease-causing mutation illuminates the protein membrane topology of the kidney-expressed prohibitin homology (PHB) domain protein podocin. J Biol Chem 2014; 289:11262-11271. [PMID: 24596097 DOI: 10.1074/jbc.m113.521773] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Mutations in the NPHS2 gene are a major cause of steroid-resistant nephrotic syndrome, a severe human kidney disorder. The NPHS2 gene product podocin is a key component of the slit diaphragm cell junction at the kidney filtration barrier and part of a multiprotein-lipid supercomplex. A similar complex with the podocin ortholog MEC-2 is required for touch sensation in Caenorhabditis elegans. Although podocin and MEC-2 are membrane-associated proteins with a predicted hairpin-like structure and amino and carboxyl termini facing the cytoplasm, this membrane topology has not been convincingly confirmed. One particular mutation that causes kidney disease in humans (podocin(P118L)) has also been identified in C. elegans in genetic screens for touch insensitivity (MEC-2(P134S)). Here we show that both mutant proteins, in contrast to the wild-type variants, are N-glycosylated because of the fact that the mutant C termini project extracellularly. Podocin(P118L) and MEC-2(P134S) did not fractionate in detergent-resistant membrane domains. Moreover, mutant podocin failed to activate the ion channel TRPC6, which is part of the multiprotein-lipid supercomplex, indicative of the fact that cholesterol recruitment to the ion channels, an intrinsic function of both proteins, requires C termini facing the cytoplasmic leaflet of the plasma membrane. Taken together, this study demonstrates that the carboxyl terminus of podocin/MEC-2 has to be placed at the inner leaflet of the plasma membrane to mediate cholesterol binding and contribute to ion channel activity, a prerequisite for mechanosensation and the integrity of the kidney filtration barrier.
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Affiliation(s)
- Eva-Maria Schurek
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Linus A Völker
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Judit Tax
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Tobias Lamkemeyer
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-associated Diseases, University of Cologne, 50931 Cologne, Germany
| | - Markus M Rinschen
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
| | - Denise Ungrue
- Cologne Excellence Cluster on Cellular Stress Responses in Ageing-associated Diseases, University of Cologne, 50931 Cologne, Germany
| | - John E Kratz
- Department of Biological Sciences, Columbia University, New York, New York 10027-6902, and
| | - Lalida Sirianant
- Department of Physiology, University of Regensburg, 93053 Regensburg, Germany
| | - Karl Kunzelmann
- Department of Physiology, University of Regensburg, 93053 Regensburg, Germany
| | - Martin Chalfie
- Department of Biological Sciences, Columbia University, New York, New York 10027-6902, and
| | - Bernhard Schermer
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany,; Cologne Excellence Cluster on Cellular Stress Responses in Ageing-associated Diseases, University of Cologne, 50931 Cologne, Germany,; Systems Biology of Ageing Cologne, University of Cologne, 50931 Cologne, Germany
| | - Thomas Benzing
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany,; Cologne Excellence Cluster on Cellular Stress Responses in Ageing-associated Diseases, University of Cologne, 50931 Cologne, Germany,; Systems Biology of Ageing Cologne, University of Cologne, 50931 Cologne, Germany,.
| | - Martin Höhne
- Systems Biology of Ageing Cologne, University of Cologne, 50931 Cologne, Germany,; Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Cologne, Germany
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35
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Tan K, Chhor G, Binkowski TA, Jedrzejczak RP, Makowska-Grzyska M, Joachimiak A. Sensor domain of histidine kinase KinB of Pseudomonas: a helix-swapped dimer. J Biol Chem 2014; 289:12232-44. [PMID: 24573685 DOI: 10.1074/jbc.m113.514836] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The overproduction of polysaccharide alginate is responsible for the formation of mucus in the lungs of cystic fibrosis patients. Histidine kinase KinB of the KinB-AlgB two-component system in Pseudomonas aeruginosa acts as a negative regulator of alginate biosynthesis. The modular architecture of KinB is similar to other histidine kinases. However, its periplasmic signal sensor domain is unique and is found only in the Pseudomonas genus. Here, we present the first crystal structures of the KinB sensor domain. The domain is a dimer in solution, and in the crystal it shows an atypical dimer of a helix-swapped four-helix bundle. A positively charged cavity is formed on the dimer interface and involves several strictly conserved residues, including Arg-60. A phosphate anion is bound asymmetrically in one of the structures. In silico docking identified several monophosphorylated sugars, including β-D-fructose 6-phosphate and β-D-mannose 6-phosphate, a precursor and an intermediate of alginate synthesis, respectively, as potential KinB ligands. Ligand binding was confirmed experimentally. Conformational transition from a symmetric to an asymmetric structure and decreasing dimer stability caused by ligand binding may be a part of the signal transduction mechanism of the KinB-AlgB two-component system.
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Affiliation(s)
- Kemin Tan
- From the Midwest Center for Structural Genomics and
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36
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Nakamura Y, Hasebe A, Takahashi K, Iijima M, Yoshimoto N, Maturana AD, Ting K, Kuroda S, Niimi T. Oligomerization-induced conformational change in the C-terminal region of Nel-like molecule 1 (NELL1) protein is necessary for the efficient mediation of murine MC3T3-E1 cell adhesion and spreading. J Biol Chem 2014; 289:9781-94. [PMID: 24563467 DOI: 10.1074/jbc.m113.507020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
NELL1 is a large oligomeric secretory glycoprotein that functions as an osteoinductive factor. NELL1 contains several conserved domains, has structural similarities to thrombospondin 1, and supports osteoblastic cell adhesion through integrins. To define the structural requirements for NELL1-mediated cell adhesion, we prepared a series of recombinant NELL1 proteins (intact, deleted, and cysteine-mutant) from a mammalian expression system and tested their activities. A deletion analysis demonstrated that the C-terminal cysteine-rich region of NELL1 is critical for the cell adhesion activity of NELL1. Reducing agent treatment decreased the cell adhesion activity of full-length NELL1 but not of its C-terminal fragments, suggesting that the intramolecular disulfide bonds within this region are not functionally necessary but that other disulfide linkages in the N-terminal region of NELL1 may be involved in cell adhesion activity. By replacing cysteine residues with serines around the coiled-coil domain of NELL1, which is responsible for oligomerization, we created a mutant NELL1 protein that was unable to form homo-oligomers, and this monomeric mutant showed substantially lower cell adhesion activity than intact NELL1. These results suggest that an oligomerization-induced conformational change in the C-terminal region of NELL1 is important for the efficient mediation of cell adhesion and spreading by NELL1.
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Affiliation(s)
- Yoko Nakamura
- From the Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Japan and
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Lanz MA, Farhat M, Klostermeier D. The acidic C-terminal tail of the GyrA subunit moderates the DNA supercoiling activity of Bacillus subtilis gyrase. J Biol Chem 2014; 289:12275-85. [PMID: 24563461 DOI: 10.1074/jbc.m114.547745] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Gyrase is a type II DNA topoisomerase that introduces negative supercoils into DNA in an ATP-dependent reaction. It consists of a topoisomerase core, formed by the N-terminal domains of the two GyrA subunits and by the two GyrB subunits, that catalyzes double-stranded DNA cleavage and passage of a second double-stranded DNA through the gap in the first. The C-terminal domains (CTDs) of the GyrA subunits form a β-pinwheel and bind DNA around their positively charged perimeter. As a result, DNA is bound as a positive supercoil that is converted into a negative supercoil by strand passage. The CTDs contain a conserved 7-amino acid motif that connects blades 1 and 6 of the β-pinwheel and is a hallmark feature of gyrases. Deletion of this so-called GyrA-box abrogates DNA bending by the CTDs and DNA-induced narrowing of the N-gate, affects T-segment presentation, reduces the coupling of DNA binding to ATP hydrolysis, and leads to supercoiling deficiency. Recently, a severe loss of supercoiling activity of Escherichia coli gyrase upon deletion of the non-conserved acidic C-terminal tail (C-tail) of the CTDs has been reported. We show here that, in contrast to E. coli gyrase, the C-tail is a very moderate negative regulator of Bacillus subtilis gyrase activity. The C-tail reduces the degree of DNA bending by the CTDs but has no effect on DNA-induced conformational changes of gyrase that precede strand passage and reduces DNA-stimulated ATPase and DNA supercoiling activities only 2-fold. Our results are in agreement with species-specific, differential regulatory effects of the C-tail in gyrases from different organisms.
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Affiliation(s)
- Martin A Lanz
- From the Institute for Physical Chemistry, University of Muenster, Corrensstrasse 30, D-48149 Muenster, Germany
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Yoon WJ, Cho YD, Kim WJ, Bae HS, Islam R, Woo KM, Baek JH, Bae SC, Ryoo HM. Prolyl isomerase Pin1-mediated conformational change and subnuclear focal accumulation of Runx2 are crucial for fibroblast growth factor 2 (FGF2)-induced osteoblast differentiation. J Biol Chem 2014; 289:8828-38. [PMID: 24509851 DOI: 10.1074/jbc.m113.516237] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fibroblast growth factor 2 (FGF2) signaling plays a pivotal role in bone growth/differentiation through the activation of osteogenic master transcription factor Runx2, which is mediated by the ERK/MAPK-dependent phosphorylation and the p300-dependent acetylation of Runx2. In this study, we found that Pin1-dependent isomerization of Runx2 is the critical step for FGF2-induced Runx2 transactivation function. We identified four serine or threonine residues in the C-terminal domain of Runx2 that are responsible for Pin1 binding and structural modification. Confocal imaging studies indicated that FGF2 treatment strongly stimulated the focal accumulation of Pin1 in the subnuclear area, which recruited Runx2. In addition, active forms of RNA polymerase-II also colocalized in the same subnuclear compartment. Dipentamethylene thiuram monosulfide, a Pin1 inhibitor, strongly attenuated their focal accumulation as well as Runx2 transactivation activity. The Pin1-mediated structural modification of Runx2 is an indispensable step connecting phosphorylation and acetylation and, consequently, transcriptional activation of Runx2 by FGF signaling. Thus, the modulation of Pin1 activity may be a target for the regulation of bone formation.
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Affiliation(s)
- Won-Joon Yoon
- From the Department of Molecular Genetics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 110-749 and
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Bahl CD, Hvorecny KL, Bridges AA, Ballok AE, Bomberger JM, Cady KC, O'Toole GA, Madden DR. Signature motifs identify an Acinetobacter Cif virulence factor with epoxide hydrolase activity. J Biol Chem 2014; 289:7460-9. [PMID: 24474692 DOI: 10.1074/jbc.m113.518092] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Endocytic recycling of the cystic fibrosis transmembrane conductance regulator (CFTR) is blocked by the CFTR inhibitory factor (Cif). Originally discovered in Pseudomonas aeruginosa, Cif is a secreted epoxide hydrolase that is transcriptionally regulated by CifR, an epoxide-sensitive repressor. In this report, we investigate a homologous protein found in strains of the emerging nosocomial pathogens Acinetobacter nosocomialis and Acinetobacter baumannii ("aCif"). Like Cif, aCif is an epoxide hydrolase that carries an N-terminal secretion signal and can be purified from culture supernatants. When applied directly to polarized airway epithelial cells, mature aCif triggers a reduction in CFTR abundance at the apical membrane. Biochemical and crystallographic studies reveal a dimeric assembly with a stereochemically conserved active site, confirming our motif-based identification of candidate Cif-like pathogenic EH sequences. Furthermore, cif expression is transcriptionally repressed by a CifR homolog ("aCifR") and is induced in the presence of epoxides. Overall, this Acinetobacter protein recapitulates the essential attributes of the Pseudomonas Cif system and thus may facilitate airway colonization in nosocomial lung infections.
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Abstract
α-Synuclein aggregation is central to the pathogenesis of several brain disorders. However, the native conformations and functions of this protein in the human brain are not precisely known. The native state of α-synuclein was probed by gel filtration coupled with native gradient gel separation, an array of antibodies with non-overlapping epitopes, and mass spectrometry. The existence of metastable conformers and stable monomer was revealed in the human brain.
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Affiliation(s)
- Neal Gould
- From the Departments of Pediatrics and Pharmacology, The Children's Hospital of Philadelphia Research Institute and
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Zeraik AE, Pereira HM, Santos YV, Brandão-Neto J, Spoerner M, Santos MS, Colnago LA, Garratt RC, Araújo APU, DeMarco R. Crystal structure of a Schistosoma mansoni septin reveals the phenomenon of strand slippage in septins dependent on the nature of the bound nucleotide. J Biol Chem 2014; 289:7799-811. [PMID: 24464615 DOI: 10.1074/jbc.m113.525352] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Septins are filament-forming GTP-binding proteins involved in important cellular events, such as cytokinesis, barrier formation, and membrane remodeling. Here, we present two crystal structures of the GTPase domain of a Schistosoma mansoni septin (SmSEPT10), one bound to GDP and the other to GTP. The structures have been solved at an unprecedented resolution for septins (1.93 and 2.1 Å, respectively), which has allowed for unambiguous structural assignment of regions previously poorly defined. Consequently, we provide a reliable model for functional interpretation and a solid foundation for future structural studies. Upon comparing the two complexes, we observe for the first time the phenomenon of a strand slippage in septins. Such slippage generates a front-back communication mechanism between the G and NC interfaces. These data provide a novel mechanistic framework for the influence of nucleotide binding to the GTPase domain, opening new possibilities for the study of the dynamics of septin filaments.
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Affiliation(s)
- Ana E Zeraik
- From the Instituto de Física de São Carlos, Universidade de São Paulo, 13563-120 São Carlos, São Paulo, Brazil
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Addis PW, Hall CJ, Bruton S, Veverka V, Wilkinson IC, Muskett FW, Renshaw PS, Prosser CE, Carrington B, Lawson ADG, Griffin R, Taylor RJ, Waters LC, Henry AJ, Carr MD. Conformational heterogeneity in antibody-protein antigen recognition: implications for high affinity protein complex formation. J Biol Chem 2014; 289:7200-7210. [PMID: 24436329 DOI: 10.1074/jbc.m113.492215] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Specific, high affinity protein-protein interactions lie at the heart of many essential biological processes, including the recognition of an apparently limitless range of foreign proteins by natural antibodies, which has been exploited to develop therapeutic antibodies. To mediate biological processes, high affinity protein complexes need to form on appropriate, relatively rapid timescales, which presents a challenge for the productive engagement of complexes with large and complex contact surfaces (∼600-1800 Å(2)). We have obtained comprehensive backbone NMR assignments for two distinct, high affinity antibody fragments (single chain variable and antigen-binding (Fab) fragments), which recognize the structurally diverse cytokines interleukin-1β (IL-1β, β-sheet) and interleukin-6 (IL-6, α-helical). NMR studies have revealed that the hearts of the antigen binding sites in both free anti-IL-1β Fab and anti-IL-6 single chain variable exist in multiple conformations, which interconvert on a timescale comparable with the rates of antibody-antigen complex formation. In addition, we have identified a conserved antigen binding-induced change in the orientation of the two variable domains. The observed conformational heterogeneity and slow dynamics at protein antigen binding sites appears to be a conserved feature of many high affinity protein-protein interfaces structurally characterized by NMR, suggesting an essential role in protein complex formation. We propose that this behavior may reflect a soft capture, protein-protein docking mechanism, facilitating formation of high affinity protein complexes on a timescale consistent with biological processes.
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Affiliation(s)
- Philip W Addis
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Catherine J Hall
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Shaun Bruton
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Vaclav Veverka
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Ian C Wilkinson
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Frederick W Muskett
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Philip S Renshaw
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom
| | - Christine E Prosser
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom; Research and Development, UCB, Slough SL1 3WE, United Kingdom
| | | | | | - Robert Griffin
- Research and Development, UCB, Slough SL1 3WE, United Kingdom
| | | | - Lorna C Waters
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom.
| | | | - Mark D Carr
- Department of Biochemistry, University of Leicester, Leicester LE1 9HN, United Kingdom.
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Mukherjee P, Wilson RC, Lahiri I, Pata JD. Three residues of the interdomain linker determine the conformation and single-base deletion fidelity of Y-family translesion polymerases. J Biol Chem 2014; 289:6323-6331. [PMID: 24415763 DOI: 10.1074/jbc.m113.537860] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dpo4 and Dbh are from two closely related Sulfolobus species and are well studied archaeal homologues of pol IV, an error prone Y-family polymerase from Escherichia coli. Despite sharing 54% amino acid identity, these polymerases display distinct mutagenic and translesion specificities. Structurally, Dpo4 and Dbh adopt different conformations because of the difference in relative orientation of their N-terminal catalytic and C-terminal DNA binding domains. Using chimeric constructs of these two polymerases, we have previously demonstrated that the interdomain linker is a major determinant of polymerase conformation, base-substitution fidelity, and abasic-site translesion synthesis. Here we find that the interdomain linker also affects the single-base deletion frequency and the mispair extension efficiency of these polymerases. Exchanging just three amino acids in the linkers of Dbh and Dpo4 is sufficient to change the fidelity by up to 30-fold, predominantly by altering the rate of correct (but not incorrect) nucleotide incorporation. Additionally, from a 2.4 Å resolution crystal structure, we have found that the three linker amino acids from Dpo4 are sufficient to allow Dbh to adopt the standard conformation of Dpo4. Thus, a small region of the interdomain linker, located more than 11 Å away from the catalytic residues, determines the fidelity of these Y-family polymerases, by controlling the alignment of substrates at the active site.
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Affiliation(s)
- Purba Mukherjee
- Wadsworth Center, New York State Department of Health, University at Albany, School of Public Health, Albany, New York 12201; Department of Biomedical Sciences, University at Albany, School of Public Health, Albany, New York 12201
| | - Ryan C Wilson
- Wadsworth Center, New York State Department of Health, University at Albany, School of Public Health, Albany, New York 12201
| | - Indrajit Lahiri
- Wadsworth Center, New York State Department of Health, University at Albany, School of Public Health, Albany, New York 12201; Department of Biomedical Sciences, University at Albany, School of Public Health, Albany, New York 12201
| | - Janice D Pata
- Wadsworth Center, New York State Department of Health, University at Albany, School of Public Health, Albany, New York 12201; Department of Biomedical Sciences, University at Albany, School of Public Health, Albany, New York 12201.
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Kocsis ZS, Sarlós K, Harami GM, Martina M, Kovács M. A nucleotide-dependent and HRDC domain-dependent structural transition in DNA-bound RecQ helicase. J Biol Chem 2014; 289:5938-49. [PMID: 24403069 DOI: 10.1074/jbc.m113.530741] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The allosteric communication between the ATP- and DNA-binding sites of RecQ helicases enables efficient coupling of ATP hydrolysis to translocation along single-stranded DNA (ssDNA) and, in turn, the restructuring of multistranded DNA substrates during genome maintenance processes. In this study, we used the tryptophan fluorescence signal of Escherichia coli RecQ helicase to decipher the kinetic mechanism of the interaction of the enzyme with ssDNA. Rapid kinetic experiments revealed that ssDNA binding occurs in a two-step mechanism in which the initial binding step is followed by a structural transition of the DNA-bound helicase. We found that the nucleotide state of RecQ greatly influences the kinetics of the detected structural transition, which leads to a high affinity DNA-clamped state in the presence of the nucleotide analog ADP-AlF4. The DNA binding mechanism is largely independent of ssDNA length, indicating the independent binding of RecQ molecules to ssDNA and the lack of significant DNA end effects. The structural transition of DNA-bound RecQ was not detected when the ssDNA binding capability of the helicase-RNase D C-terminal domain was abolished or the domain was deleted. The results shed light on the nature of conformational changes leading to processive ssDNA translocation and multistranded DNA processing by RecQ helicases.
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Affiliation(s)
- Zsuzsa S Kocsis
- From the Department of Biochemistry, ELTE-MTA "Momentum" Motor Enzymology Research Group, Eötvös University, Pázmány P. s. 1/c, H-1117 Budapest, Hungary
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Ozturk N, Selby CP, Zhong D, Sancar A. Mechanism of photosignaling by Drosophila cryptochrome: role of the redox status of the flavin chromophore. J Biol Chem 2013; 289:4634-42. [PMID: 24379403 DOI: 10.1074/jbc.m113.542498] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cryptochrome (CRY) is the primary circadian photoreceptor in Drosophila. Upon light absorption, dCRY undergoes a conformational change that enables it to bind to Timeless (dTIM), as well as to two different E3 ligases that ubiquitylate dTIM and dCRY, respectively, resulting in their proteolysis and resetting the phase of the circadian rhythm. Purified dCRY contains oxidized flavin (FADox), which is readily photoreduced to the anionic semiquinone through a set of 3 highly conserved Trp residues (Trp triad). The crystal structure of dCRY has revealed a fourth Trp (Trp-536) as a potential electron donor. Previously, we reported that the Trp triad played no role in photoinduced proteolysis of dCRY in Drosophila cells. Here we investigated the role of the Trp triad and Trp-536, and the redox status of the flavin on light-induced proteolysis of both dCRY and dTIM and resetting of the clock. We found that both oxidized (FADox) and reduced (FAD) forms of dCRY undergo light-induced conformational change in vitro that enable dCRY to bind JET and that Trp triad and Trp-536 mutations that block known or presumed intraprotein electron transfer reactions do not affect dCRY phototransduction under bright or dim light in vivo as measured by light-induced proteolysis of dCRY and dTIM in Drosophila S2R+ cells. We conclude that both oxidized and reduced forms of dCRY are capable of photosignaling.
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Affiliation(s)
- Nuri Ozturk
- From the Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599 and
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Singh H, Dai Y, Outten FW, Busenlehner LS. Escherichia coli SufE sulfur transfer protein modulates the SufS cysteine desulfurase through allosteric conformational dynamics. J Biol Chem 2013; 288:36189-200. [PMID: 24196966 PMCID: PMC3868733 DOI: 10.1074/jbc.m113.525709] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 11/05/2013] [Indexed: 11/06/2022] Open
Abstract
Fe-S clusters are critical metallocofactors required for cell function. Fe-S cluster biogenesis is carried out by assembly machinery consisting of multiple proteins. Fe-S cluster biogenesis proteins work together to mobilize sulfide and iron, form the nascent cluster, traffic the cluster to target metalloproteins, and regulate the assembly machinery in response to cellular Fe-S cluster demand. A complex series of protein-protein interactions is required for the assembly machinery to function properly. Despite considerable progress in obtaining static three-dimensional structures of the assembly proteins, little is known about transient protein-protein interactions during cluster assembly or the role of protein dynamics in the cluster assembly process. The Escherichia coli cysteine desulfurase SufS (EC 2.8.1.7) and its accessory protein SufE work together to mobilize persulfide from L-cysteine, which is then donated to the SufB Fe-S cluster scaffold. Here we use amide hydrogen/deuterium exchange mass spectrometry (HDX-MS) to characterize SufS-SufE interactions and protein dynamics in solution. HDX-MS analysis shows that SufE binds near the SufS active site to accept persulfide from Cys-364. Furthermore, SufE binding initiates allosteric changes in other parts of the SufS structure that likely affect SufS catalysis and alter SufS monomer-monomer interactions. SufE enhances the initial l-cysteine substrate binding to SufS and formation of the external aldimine with pyridoxal phosphate required for early steps in SufS catalysis. Together, these results provide a new picture of the SufS-SufE sulfur transferase pathway and suggest a more active role for SufE in promoting the SufS cysteine desulfurase reaction for Fe-S cluster assembly.
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Affiliation(s)
- Harsimran Singh
- From the Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487 and
| | - Yuyuan Dai
- the Department of Chemistry and Biochemistry, The University of South Carolina, Columbia, South Carolina 29208
| | - F. Wayne Outten
- the Department of Chemistry and Biochemistry, The University of South Carolina, Columbia, South Carolina 29208
| | - Laura S. Busenlehner
- From the Department of Chemistry, The University of Alabama, Tuscaloosa, Alabama 35487 and
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Dahiya V, Chaudhuri TK. Chaperones GroEL/GroES accelerate the refolding of a multidomain protein through modulating on-pathway intermediates. J Biol Chem 2013; 289:286-98. [PMID: 24247249 DOI: 10.1074/jbc.m113.518373] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Despite a vast amount information on the interplay of GroEL, GroES, and ATP in chaperone-assisted folding, the molecular details on the conformational dynamics of folding polypeptide during its GroEL/GroES-assisted folding cycle is quite limited. Practically no such studies have been reported to date on large proteins, which often have difficulty folding in vitro. The effect of the GroEL/GroES chaperonin system on the folding pathway of an 82-kDa slow folding protein, malate synthase G (MSG), was investigated. GroEL bound to the burst phase intermediate of MSG and accelerated the slowest kinetic phase associated with the formation of native topology in the spontaneous folding pathway. GroEL slowly induced conformational changes on the bound burst phase intermediate, which was then transformed into a more folding-compatible form. Subsequent addition of ATP or GroES/ATP to the GroEL-MSG complex led to the formation of the native state via a compact intermediate with the rate several times faster than that of spontaneous refolding. The presence of GroES doubled the ATP-dependent reactivation rate of bound MSG by preventing multiple cycles of its GroEL binding and release. Because GroES bound to the trans side of GroEL-MSG complex, it may be anticipated that confinement of the substrate underneath the co-chaperone is not required for accelerating the rate in the assisted folding pathway. The potential role of GroEL/GroES in assisted folding is most likely to modulate the conformation of MSG intermediates that can fold faster and thereby eliminate the possibility of partial aggregation caused by the slow folding intermediates during its spontaneous refolding pathway.
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Affiliation(s)
- Vinay Dahiya
- From the Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, Hauz Khas, New Delhi 110016, India
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Anders K, Daminelli-Widany G, Mroginski MA, von Stetten D, Essen LO. Structure of the cyanobacterial phytochrome 2 photosensor implies a tryptophan switch for phytochrome signaling. J Biol Chem 2013; 288:35714-25. [PMID: 24174528 DOI: 10.1074/jbc.m113.510461] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phytochromes are highly versatile photoreceptors, which occur ubiquitously in plants as well as in many light-responsive microorganisms. Here, photosynthetic cyanobacteria utilize up to three different phytochrome architectures, where only the plant-like and the single-domain cyanobacteriochromes are structurally characterized so far. Cph2 represents a third group in Synechocystis species and affects their capability of phototaxis by controlling c-di-GMP synthesis and degradation. The 2.6-Å crystal structure of its red/far-red responsive photosensory module in the Pr state reveals a tandem-GAF bidomain that lacks the figure-of-eight knot of the plant/cph1 subfamily. Its covalently attached phycocyanobilin chromophore adopts a highly tilted ZZZssa conformation with a novel set of interactions between its propionates and the GAF1 domain. The tongue-like protrusion from the GAF2 domain interacts with the GAF1-bound chromophore via its conserved PRXSF, WXE, and W(G/A)G motifs. Mutagenesis showed that the integrity of the tongue is indispensable for Pr → Pfr photoconversion and involves a swap of the motifs' tryptophans within the tongue-GAF1 interface. This "Trp switch" is supposed to be a crucial element for the photochromicity of all multidomain phytochromes.
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Affiliation(s)
- Katrin Anders
- From the Department of Chemistry, Biomedical Research Centre, Philipps-Universität, D-35032 Marburg, Germany
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Abstract
Recent studies have documented the ability of prothrombin to spontaneously convert to the mature protease thrombin when Arg-320 becomes exposed to solvent for proteolytic attack upon mutation of residues in the activation domain. Whether prothrombin autoactivation occurs in the wild-type under conditions relevant to physiology remains unknown. Here, we report that binding of histone H4 to prothrombin under physiological conditions generates thrombin by autoactivation. The effect is abrogated by mutation of the catalytic Ser-525 and requires the presence of the Gla domain. Fluorescence titrations document direct binding of histone H4 to prothrombin with an affinity in the low nm range. Stopped flow data and luminescence resonance energy transfer measurements indicate that the binding mechanism obeys conformational selection. Among the two conformations of prothrombin, collapsed and fully extended, histone H4 binds selectively to the collapsed form and induces a transition toward a new conformation where the distance between Ser-101 in kringle-1 and Ser-210 in kringle-2 increases by 13 Å. These findings confirm the molecular plasticity of prothrombin emerged from recent structural studies and suggest that different conformations of the inter-kringle linker domain determine the functional behavior of prothrombin. The results also broaden our mechanistic understanding of the prothrombotic phenotype observed during cellular damage due to the release of histones in the blood stream. Prothrombin autoactivation induced by histone H4 emerges as a mechanism of pathophysiological relevance through which thrombin is generated independently of activation of the coagulation cascade.
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Affiliation(s)
- Sergio Barranco-Medina
- From the Edward A. Doisy Department of Biochemistry and Molecular Biology, Saint Louis University School of Medicine, St. Louis, Missouri 63104
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Hyde AS, Thelen AM, Barycki JJ, Simpson MA. UDP-glucose dehydrogenase activity and optimal downstream cellular function require dynamic reorganization at the dimer-dimer subunit interfaces. J Biol Chem 2013; 288:35049-57. [PMID: 24145036 DOI: 10.1074/jbc.m113.519090] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
UDP-glucose dehydrogenase (UGDH) provides precursors for steroid elimination, hyaluronan production, and glycosaminoglycan synthesis. The wild-type UGDH enzyme purifies in a hexamer-dimer equilibrium and transiently undergoes dynamic motion that exposes the dimer-dimer interface during catalysis. In the current study we created and characterized point mutations that yielded exclusively dimeric species (obligate dimer, T325D), dimeric species that could be induced to form hexamers in the ternary complex with substrate and cofactor (T325A), and a previously described exclusively hexameric species (UGDHΔ132) to investigate the role of quaternary structure in regulation of the enzyme. Characterization of the purified enzymes revealed a significant decrease in the enzymatic activity of the obligate dimer and hexamer mutants. Kinetic analysis of wild-type UGDH and the inducible hexamer, T325A, showed that upon increasing enzyme concentration, which favors the hexameric species, activity was modestly decreased and exhibited cooperativity. In contrast, cooperative kinetic behavior was not observed in the obligate dimer, T325D. These observations suggest that the regulation of the quaternary assembly of the enzyme is essential for optimal activity and allosteric regulation. Comparison of kinetic and thermal stability parameters revealed structurally dependent properties consistent with a role for controlled assembly and disassembly of the hexamer in the regulation of UGDH. Finally, both T325A and T325D mutants were significantly less efficient in promoting downstream hyaluronan production by HEK293 cells. These data support a model that requires an operational dimer-hexamer equilibrium to function efficiently and preserve regulated activity in the cell.
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Affiliation(s)
- Annastasia S Hyde
- From the Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588-0664
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