1
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Suryajaya W, Biswas T, Shahabi S, Mealka M, Huxford T, Ghosh G. HDX-MS Analysis of Catalytic Activation of IKK2 in the IκB Kinase Complex. Biochemistry 2024; 63:2323-2334. [PMID: 39185716 DOI: 10.1021/acs.biochem.4c00202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/27/2024]
Abstract
The IκB Kinase (IKK) complex, containing catalytic IKK2 and noncatalytic NEMO subunits, plays essential roles in the induction of transcription factors of the NF-κB family. Catalytic activation of IKK2 via phosphorylation of its activation loop is promoted upon noncovalent association of linear or K63-linked polyubiquitin chains to NEMO within the IKK complex. The mechanisms of this activation remain speculative. To investigate interaction dynamics within the IKK complex during activation of IKK2, we conducted hydrogen-deuterium exchange coupled with mass spectrometry (HDX-MS) on NEMO and IKK2 proteins in their free and complex-bound states. Altered proton exchange profiles were observed in both IKK2 and NEMO upon complex formation, and changes were consistent with the involvement of distinct regions throughout the entire length of both proteins, including previously uncharacterized segments, in direct or allosteric interactions. Association with linear tetraubiquitin (Ub4) affected multiple regions of the IKK2:NEMO complex, in addition to previously identified interaction sites on NEMO. Intriguingly, observed enhanced solvent accessibility of the IKK2 activation loop within the IKK2:NEMO:Ub4 complex, coupled with contrasting protection of surrounding segments of the catalytic subunit, suggests an allosteric role for NEMO:Ub4 in priming IKK2 for phosphorylation-dependent catalytic activation.
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Affiliation(s)
- William Suryajaya
- Department of Chemistry & Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0357, United States
| | - Tapan Biswas
- Department of Chemistry & Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0357, United States
| | - Shandy Shahabi
- Department of Chemistry & Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0357, United States
| | - Matthew Mealka
- Structural Biochemistry Laboratory Department of Chemistry & Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, California 92182-1030, United States
| | - Tom Huxford
- Structural Biochemistry Laboratory Department of Chemistry & Biochemistry, San Diego State University, 5500 Campanile Drive, San Diego, California 92182-1030, United States
| | - Gourisankar Ghosh
- Department of Chemistry & Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0357, United States
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2
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Pan W, Biswas T, Shahabi S, Suryajaya W, Vasquez A, Du Q, Ghosh G, Wang VYF. Phosphorylation-induced flexibility of proto-oncogenic Bcl3 regulates transcriptional activation by NF-κB p52 homodimer. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.30.601400. [PMID: 38979190 PMCID: PMC11230411 DOI: 10.1101/2024.06.30.601400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
The overexpression of proto-oncogene Bcl3 is observed in various cancers. Bcl3 is extensively phosphorylated and associates with homodimers of NF-κB p50 and p52 to regulate transcription. Through cellular and biochemical assays, we observed that phospho-mimetic Glu substitution at Ser366 in addition to previously studied Ser33, 114 and 446 is necessary to switch Bcl3 from an IκB-like inhibitor to a transcriptional activator. To study interactive features of p52 and Bcl3, and phosphorylation- mediated changes in Bcl3 that regulate DNA-binding by p52, we performed HDX-MS of both Bcl3 and p52 within various complexes. Nature of interactions within Bcl3:(p52:p52) complex in presence and absence of DNA, differential flexibility of Bcl3, and allosteric changes in Bcl3 upon phospho-modifications revealed why a facile accommodation of DNA requires phosphorylation. The inhibitory nature of unphosphorylated Bcl3 on DNA binding by p52:p52 also relieved by a C-terminal deletion of Bcl3. Overall, this study revealed mechanistic bases of how Bcl3 phosphorylation regulates transcriptional potential of NF-κB and intricate cell physiology, a dysregulation of which can lead to cancers.
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3
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Retamal-Farfán I, González-Higueras J, Galaz-Davison P, Rivera M, Ramírez-Sarmiento CA. Exploring the structural acrobatics of fold-switching proteins using simplified structure-based models. Biophys Rev 2023; 15:787-799. [PMID: 37681096 PMCID: PMC10480104 DOI: 10.1007/s12551-023-01087-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 06/22/2023] [Indexed: 09/09/2023] Open
Abstract
Metamorphic proteins are a paradigm of the protein folding process, by encoding two or more native states, highly dissimilar in terms of their secondary, tertiary, and even quaternary structure, on a single amino acid sequence. Moreover, these proteins structurally interconvert between these native states in a reversible manner at biologically relevant timescales as a result of different environmental cues. The large-scale rearrangements experienced by these proteins, and their sometimes high mass interacting partners that trigger their metamorphosis, makes the computational and experimental study of their structural interconversion challenging. Here, we present our efforts in studying the refolding landscapes of two quintessential metamorphic proteins, RfaH and KaiB, using simplified dual-basin structure-based models (SBMs), rigorously footed on the energy landscape theory of protein folding and the principle of minimal frustration. By using coarse-grained models in which the native contacts and bonded interactions extracted from the available experimental structures of the two native states of RfaH and KaiB are merged into a single Hamiltonian, dual-basin SBM models can be generated and savvily calibrated to explore their fold-switch in a reversible manner in molecular dynamics simulations. We also describe how some of the insights offered by these simulations have driven the design of experiments and the validation of the conformational ensembles and refolding routes observed using this simple and computationally efficient models.
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Affiliation(s)
- Ignacio Retamal-Farfán
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, 7820436 Santiago, Chile
- ANID — Millennium Science Initiative Program — Millennium Institute for Integrative Biology (iBio), Santiago, Chile
| | - Jorge González-Higueras
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, 7820436 Santiago, Chile
- ANID — Millennium Science Initiative Program — Millennium Institute for Integrative Biology (iBio), Santiago, Chile
| | - Pablo Galaz-Davison
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, 7820436 Santiago, Chile
- ANID — Millennium Science Initiative Program — Millennium Institute for Integrative Biology (iBio), Santiago, Chile
| | - Maira Rivera
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, 7820436 Santiago, Chile
- Department of Chemistry, Faculty of Science, McGill University, Montreal, Quebec H3A 0B8 Canada
| | - César A. Ramírez-Sarmiento
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, 7820436 Santiago, Chile
- ANID — Millennium Science Initiative Program — Millennium Institute for Integrative Biology (iBio), Santiago, Chile
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4
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Jethva PN, Gross ML. Hydrogen Deuterium Exchange and other Mass Spectrometry-based Approaches for Epitope Mapping. FRONTIERS IN ANALYTICAL SCIENCE 2023; 3:1118749. [PMID: 37746528 PMCID: PMC10512744 DOI: 10.3389/frans.2023.1118749] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
Antigen-antibody interactions are a fundamental subset of protein-protein interactions responsible for the "survival of the fittest". Determining the interacting interface of the antigen, called an epitope, and that on the antibody, called a paratope, is crucial to antibody development. Because each antigen presents multiple epitopes (unique footprints), sophisticated approaches are required to determine the target region for a given antibody. Although X-ray crystallography, Cryo-EM, and nuclear magnetic resonance can provide atomic details of an epitope, they are often laborious, poor in throughput, and insensitive. Mass spectrometry-based approaches offer rapid turnaround, intermediate structural resolution, and virtually no size limit for the antigen, making them a vital approach for epitope mapping. In this review, we describe in detail the principles of hydrogen deuterium exchange mass spectrometry in application to epitope mapping. We also show that a combination of MS-based approaches can assist or complement epitope mapping and push the limit of structural resolution to the residue level. We describe in detail the MS methods used in epitope mapping, provide our perspective about the approaches, and focus on elucidating the role that HDX-MS is playing now and in the future by organizing a discussion centered around several improvements in prototype instrument/applications used for epitope mapping. At the end, we provide a tabular summary of the current literature on HDX-MS-based epitope mapping.
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Affiliation(s)
- Prashant N. Jethva
- Department of Chemistry, Washington University in St. Louis, St Louis, MO 63130, USA
| | - Michael L. Gross
- Department of Chemistry, Washington University in St. Louis, St Louis, MO 63130, USA
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5
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Samsudin F, Raghuvamsi P, Petruk G, Puthia M, Petrlova J, MacAry P, Anand GS, Bond PJ, Schmidtchen A. SARS-CoV-2 spike protein as a bacterial lipopolysaccharide delivery system in an overzealous inflammatory cascade. J Mol Cell Biol 2023; 14:6761401. [PMID: 36240490 PMCID: PMC9940780 DOI: 10.1093/jmcb/mjac058] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 10/11/2022] [Indexed: 11/14/2022] Open
Abstract
Accumulating evidence indicates a potential role for bacterial lipopolysaccharide (LPS) in the overactivation of the immune response during SARS-CoV-2 infection. LPS is recognized by Toll-like receptor 4, mediating proinflammatory effects. We previously reported that LPS directly interacts with SARS-CoV-2 spike (S) protein and enhances proinflammatory activities. Using native gel electrophoresis and hydrogen-deuterium exchange mass spectrometry, we showed that LPS binds to multiple hydrophobic pockets spanning both the S1 and S2 subunits of the S protein. Molecular simulations validated by a microscale thermophoresis binding assay revealed that LPS binds to the S2 pocket with a lower affinity compared to S1, suggesting a role as an intermediate in LPS transfer. Congruently, nuclear factor-kappa B (NF-κB) activation in monocytic THP-1 cells is strongly boosted by S2. Using NF-κB reporter mice followed by bioimaging, a boosting effect was observed for both S1 and S2, with the former potentially facilitated by proteolysis. The Omicron S variant binds to LPS, but with reduced affinity and LPS boosting in vitro and in vivo. Taken together, the data provide a molecular mechanism by which S protein augments LPS-mediated hyperinflammation.
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Affiliation(s)
- Firdaus Samsudin
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore 138671, Singapore
| | - Palur Raghuvamsi
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore 138671, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Ganna Petruk
- Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, SE-22184 Lund, Sweden
| | - Manoj Puthia
- Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, SE-22184 Lund, Sweden
| | - Jitka Petrlova
- Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, SE-22184 Lund, Sweden
| | - Paul MacAry
- Life Sciences Institute, Centre for Life Sciences, National University of Singapore, Singapore 117546, Singapore
| | - Ganesh S Anand
- Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore.,Department of Chemistry, The Pennsylvania State University, PA 16801, USA
| | - Peter J Bond
- Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore 138671, Singapore.,Department of Biological Sciences, National University of Singapore, Singapore 117543, Singapore
| | - Artur Schmidtchen
- Division of Dermatology and Venereology, Department of Clinical Sciences, Lund University, SE-22184 Lund, Sweden.,Copenhagen Wound Healing Center, Bispebjerg Hospital, Department of Biomedical Sciences, University of Copenhagen, DK-2400 Copenhagen, Denmark
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6
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Grønnemose AL, Østerlund EC, Otzen DE, Jørgensen TJD. EGCG has Dual and Opposing Effects on the N-terminal Region of Self-associating α-synuclein Oligomers. J Mol Biol 2022; 434:167855. [PMID: 36240861 DOI: 10.1016/j.jmb.2022.167855] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 09/11/2022] [Accepted: 10/06/2022] [Indexed: 11/06/2022]
Abstract
Oligomers of the protein α-synuclein (α-syn) are thought to be a major toxic species in Parkinson's disease, particularly through their ability to permeabilize cell membranes. The green tea polyphenol epigallocatechin gallate (EGCG) has been found to reduce this ability. We have analyzed α-syn oligomer dynamics and interconversion by H/D exchange monitored by mass spectrometry (HDX-MS). Our results show that the two oligomers OI and OII co-exist in equilibrium; OI is a multimer of OII and its dissociation can be followed by HDX-MS by virtue of the correlated exchange of the N-terminal region. Urea destabilizes the α-syn oligomers, dissociating OI to OII and monomers. Oligomers exposed to EGCG undergo Met oxidation. Intriguingly, EGCG induces an oxidation-dependent effect on the structure of the N-terminal region. For the non-oxidized N-terminal region, EGCG increases the stability of the folded structure as measured by a higher level of protection against H/D exchange. In contrast, protection is clearly abrogated in the Met oxidized N-terminal region. Having a non-oxidized and disordered N-terminal region is known to be essential for efficient membrane binding. Therefore, our results suggest that the combined effect of a structural stabilization of the non-oxidized N-terminal region and the presence of a disordered oxidized N-terminal region renders the oligomers less cytotoxic by decreasing the ability of the N-terminal region to bind to cell membranes and facilitate their permeabilization.
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Affiliation(s)
- Anne Louise Grønnemose
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark; Department of Biochemistry and Molecular Biology (BMB), University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Eva Christina Østerlund
- Department of Biochemistry and Molecular Biology (BMB), University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark
| | - Daniel Erik Otzen
- Interdisciplinary Nanoscience Centre (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark.
| | - Thomas J D Jørgensen
- Department of Biochemistry and Molecular Biology (BMB), University of Southern Denmark, Campusvej 55, 5230 Odense M, Denmark.
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7
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Artsimovitch I, Ramírez-Sarmiento CA. Metamorphic proteins under a computational microscope: Lessons from a fold-switching RfaH protein. Comput Struct Biotechnol J 2022; 20:5824-5837. [PMID: 36382197 PMCID: PMC9630627 DOI: 10.1016/j.csbj.2022.10.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 10/18/2022] [Accepted: 10/18/2022] [Indexed: 11/28/2022] Open
Abstract
Metamorphic proteins constitute unexpected paradigms of the protein folding problem, as their sequences encode two alternative folds, which reversibly interconvert within biologically relevant timescales to trigger different cellular responses. Once considered a rare aberration, metamorphism may be common among proteins that must respond to rapidly changing environments, exemplified by NusG-like proteins, the only transcription factors present in every domain of life. RfaH, a specialized paralog of bacterial NusG, undergoes an all-α to all-β domain switch to activate expression of virulence and conjugation genes in many animal and plant pathogens and is the quintessential example of a metamorphic protein. The dramatic nature of RfaH structural transformation and the richness of its evolutionary history makes for an excellent model for studying how metamorphic proteins switch folds. Here, we summarize the structural and functional evidence that sparked the discovery of RfaH as a metamorphic protein, the experimental and computational approaches that enabled the description of the molecular mechanism and refolding pathways of its structural interconversion, and the ongoing efforts to find signatures and general properties to ultimately describe the protein metamorphome.
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Affiliation(s)
- Irina Artsimovitch
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - César A. Ramírez-Sarmiento
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
- ANID, Millennium Science Initiative Program, Millennium Institute for Integrative Biology (iBio), Santiago, Chile
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8
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Reiter KH, Zelter A, Janowska MK, Riffle M, Shulman N, MacLean BX, Tamura K, Chambers MC, MacCoss MJ, Davis TN, Guttman M, Brzovic PS, Klevit RE. Cullin-independent recognition of HHARI substrates by a dynamic RBR catalytic domain. Structure 2022; 30:1269-1284.e6. [PMID: 35716664 PMCID: PMC9444911 DOI: 10.1016/j.str.2022.05.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 04/15/2022] [Accepted: 05/24/2022] [Indexed: 11/27/2022]
Abstract
RING-between-RING (RBR) E3 ligases mediate ubiquitin transfer through an obligate E3-ubiquitin thioester intermediate prior to substrate ubiquitination. Although RBRs share a conserved catalytic module, substrate recruitment mechanisms remain enigmatic, and the relevant domains have yet to be identified for any member of the class. Here we characterize the interaction between the auto-inhibited RBR, HHARI (AriH1), and its target protein, 4EHP, using a combination of XL-MS, HDX-MS, NMR, and biochemical studies. The results show that (1) a di-aromatic surface on the catalytic HHARI Rcat domain forms a binding platform for substrates and (2) a phosphomimetic mutation on the auto-inhibitory Ariadne domain of HHARI promotes release and reorientation of Rcat for transthiolation and substrate modification. The findings identify a direct binding interaction between a RING-between-RING ligase and its substrate and suggest a general model for RBR substrate recognition.
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Affiliation(s)
- Katherine H Reiter
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Alex Zelter
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Maria K Janowska
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Michael Riffle
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Nicholas Shulman
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Brendan X MacLean
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Kaipo Tamura
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Matthew C Chambers
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Michael J MacCoss
- Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA
| | - Trisha N Davis
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Miklos Guttman
- Department of Medicinal Chemistry, University of Washington, Seattle, WA 98195, USA
| | - Peter S Brzovic
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA
| | - Rachel E Klevit
- Department of Biochemistry, University of Washington, Seattle, WA 98195, USA.
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9
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Gao S, Klinman JP. Functional roles of enzyme dynamics in accelerating active site chemistry: Emerging techniques and changing concepts. Curr Opin Struct Biol 2022; 75:102434. [PMID: 35872562 PMCID: PMC9901422 DOI: 10.1016/j.sbi.2022.102434] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/15/2022] [Accepted: 06/21/2022] [Indexed: 02/08/2023]
Abstract
With the growing acceptance of the contribution of protein conformational ensembles to enzyme catalysis and regulation, research in the field of protein dynamics has shifted toward an understanding of the atomistic properties of protein dynamical networks and the mechanisms and time scales that control such behavior. A full description of an enzymatic reaction coordinate is expected to extend beyond the active site and include site-specific networks that communicate with the protein/water interface. Advances in experimental tools for the spatial resolution of thermal activation pathways are being complemented by biophysical methods for visualizing dynamics in real time. An emerging multidimensional model integrates the impacts of bound substrate/effector on the distribution of protein substates that are in rapid equilibration near room temperature with reaction-specific protein embedded heat transfer conduits.
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Affiliation(s)
- Shuaihua Gao
- Department of Chemistry, University of California, Berkeley, CA, 94720, United States; California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, United States. https://twitter.com/S_H_Gao
| | - Judith P Klinman
- Department of Chemistry, University of California, Berkeley, CA, 94720, United States; California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, United States; Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, United States.
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10
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Molina JA, Galaz-Davison P, Komives EA, Artsimovitch I, Ramírez-Sarmiento CA. Allosteric couplings upon binding of RfaH to transcription elongation complexes. Nucleic Acids Res 2022; 50:6384-6397. [PMID: 35670666 PMCID: PMC9226497 DOI: 10.1093/nar/gkac453] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 05/07/2022] [Accepted: 05/18/2022] [Indexed: 12/03/2022] Open
Abstract
In every domain of life, NusG-like proteins bind to the elongating RNA polymerase (RNAP) to support processive RNA synthesis and to couple transcription to ongoing cellular processes. Structures of factor-bound transcription elongation complexes (TECs) reveal similar contacts to RNAP, consistent with a shared mechanism of action. However, NusG homologs differ in their regulatory roles, modes of recruitment, and effects on RNA synthesis. Some of these differences could be due to conformational changes in RNAP and NusG-like proteins, which cannot be captured in static structures. Here, we employed hydrogen-deuterium exchange mass spectrometry to investigate changes in local and non-local structural dynamics of Escherichia coli NusG and its paralog RfaH, which have opposite effects on expression of xenogenes, upon binding to TEC. We found that NusG and RfaH regions that bind RNAP became solvent-protected in factor-bound TECs, whereas RNAP regions that interact with both factors showed opposite deuterium uptake changes when bound to NusG or RfaH. Additional changes far from the factor-binding site were observed only with RfaH. Our results provide insights into differences in structural dynamics exerted by NusG and RfaH during binding to TEC, which may explain their different functional outcomes and allosteric regulation of transcriptional pausing by RfaH.
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Affiliation(s)
- José Alejandro Molina
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile
| | - Pablo Galaz-Davison
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile
| | - Elizabeth A Komives
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Irina Artsimovitch
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - César A Ramírez-Sarmiento
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile
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11
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Devaurs D, Antunes DA, Borysik AJ. Computational Modeling of Molecular Structures Guided by Hydrogen-Exchange Data. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2022; 33:215-237. [PMID: 35077179 DOI: 10.1021/jasms.1c00328] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Data produced by hydrogen-exchange monitoring experiments have been used in structural studies of molecules for several decades. Despite uncertainties about the structural determinants of hydrogen exchange itself, such data have successfully helped guide the structural modeling of challenging molecular systems, such as membrane proteins or large macromolecular complexes. As hydrogen-exchange monitoring provides information on the dynamics of molecules in solution, it can complement other experimental techniques in so-called integrative modeling approaches. However, hydrogen-exchange data have often only been used to qualitatively assess molecular structures produced by computational modeling tools. In this paper, we look beyond qualitative approaches and survey the various paradigms under which hydrogen-exchange data have been used to quantitatively guide the computational modeling of molecular structures. Although numerous prediction models have been proposed to link molecular structure and hydrogen exchange, none of them has been widely accepted by the structural biology community. Here, we present as many hydrogen-exchange prediction models as we could find in the literature, with the aim of providing the first exhaustive list of its kind. From purely structure-based models to so-called fractional-population models or knowledge-based models, the field is quite vast. We aspire for this paper to become a resource for practitioners to gain a broader perspective on the field and guide research toward the definition of better prediction models. This will eventually improve synergies between hydrogen-exchange monitoring and molecular modeling.
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Affiliation(s)
- Didier Devaurs
- MRC Institute of Genetics and Cancer, University of Edinburgh, Edinburgh EH4 2XU, U.K
| | - Dinler A Antunes
- Department of Biology and Biochemistry, University of Houston, Houston, Texas 77005, United States
| | - Antoni J Borysik
- Department of Chemistry, King's College London, London SE1 1DB, U.K
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12
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Human FoxP Transcription Factors as Tractable Models of the Evolution and Functional Outcomes of Three-Dimensional Domain Swapping. Int J Mol Sci 2021; 22:ijms221910296. [PMID: 34638644 PMCID: PMC8508939 DOI: 10.3390/ijms221910296] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 09/21/2021] [Accepted: 09/22/2021] [Indexed: 01/18/2023] Open
Abstract
The association of two or more proteins to adopt a quaternary complex is one of the most widespread mechanisms by which protein function is modulated. In this scenario, three-dimensional domain swapping (3D-DS) constitutes one plausible pathway for the evolution of protein oligomerization that exploits readily available intramolecular contacts to be established in an intermolecular fashion. However, analysis of the oligomerization kinetics and thermodynamics of most extant 3D-DS proteins shows its dependence on protein unfolding, obscuring the elucidation of the emergence of 3D-DS during evolution, its occurrence under physiological conditions, and its biological relevance. Here, we describe the human FoxP subfamily of transcription factors as a feasible model to study the evolution of 3D-DS, due to their significantly faster dissociation and dimerization kinetics and lower dissociation constants in comparison to most 3D-DS models. Through the biophysical and functional characterization of FoxP proteins, relevant structural aspects highlighting the evolutionary adaptations of these proteins to enable efficient 3D-DS have been ascertained. Most biophysical studies on FoxP suggest that the dynamics of the polypeptide chain are crucial to decrease the energy barrier of 3D-DS, enabling its fast oligomerization under physiological conditions. Moreover, comparison of biophysical parameters between human FoxP proteins in the context of their minute sequence differences suggests differential evolutionary strategies to favor homoassociation and presages the possibility of heteroassociations, with direct impacts in their gene regulation function.
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13
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James EI, Murphree TA, Vorauer C, Engen JR, Guttman M. Advances in Hydrogen/Deuterium Exchange Mass Spectrometry and the Pursuit of Challenging Biological Systems. Chem Rev 2021; 122:7562-7623. [PMID: 34493042 PMCID: PMC9053315 DOI: 10.1021/acs.chemrev.1c00279] [Citation(s) in RCA: 102] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
![]()
Solution-phase hydrogen/deuterium
exchange (HDX) coupled to mass
spectrometry (MS) is a widespread tool for structural analysis across
academia and the biopharmaceutical industry. By monitoring the exchangeability
of backbone amide protons, HDX-MS can reveal information about higher-order
structure and dynamics throughout a protein, can track protein folding
pathways, map interaction sites, and assess conformational states
of protein samples. The combination of the versatility of the hydrogen/deuterium
exchange reaction with the sensitivity of mass spectrometry has enabled
the study of extremely challenging protein systems, some of which
cannot be suitably studied using other techniques. Improvements over
the past three decades have continually increased throughput, robustness,
and expanded the limits of what is feasible for HDX-MS investigations.
To provide an overview for researchers seeking to utilize and derive
the most from HDX-MS for protein structural analysis, we summarize
the fundamental principles, basic methodology, strengths and weaknesses,
and the established applications of HDX-MS while highlighting new
developments and applications.
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Affiliation(s)
- Ellie I James
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Taylor A Murphree
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Clint Vorauer
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - John R Engen
- Department of Chemistry & Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Miklos Guttman
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington 98195, United States
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14
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Narang D, James DA, Balmer MT, Wilson DJ. Protein Footprinting, Conformational Dynamics, and Core Interface-Adjacent Neutralization "Hotspots" in the SARS-CoV-2 Spike Protein Receptor Binding Domain/Human ACE2 Interaction. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:1593-1600. [PMID: 33794092 PMCID: PMC8029444 DOI: 10.1021/jasms.0c00465] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/22/2021] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
The novel severe respiratory syndrome-like coronavirus (SARS-CoV-2) causes COVID-19 in humans and is responsible for one of the most destructive pandemics of the last century. At the root of SARS-CoV infection is the interaction between the viral spike protein and the human angiotensin converting enzyme 2 protein, which allows the virus to gain entry into host cells through endocytosis. In this work, we apply hydrogen-deuterium exchange mass spectrometry (HDX-MS) to provide a detailed view of the functional footprint and conformational dynamics associated with this interaction. Our results broadly agree with the binding interface derived from high resolution X-ray crystal structure data but also provide insights into shifts in structure and dynamics that accompany complexation, including some that occur immediately outside of the core binding interface. We propose that dampening of these "binding-site adjacent" dynamic shifts could represent a mechanism for neutralizing activity in a multitude of spike protein-targeted mAbs that have been found to specifically bind these "peripheral" sites. Our results highlight the unique capacity of HDX-MS to detect potential neutralization "hotspots" outside of the core binding interfaces defined by high resolution structural data.
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Affiliation(s)
- Dominic Narang
- Department of Chemistry, York
University, Toronto M3J 1P3, Ontario, Canada
| | - D. Andrew James
- Sanofi Pasteur Limited,
1755 Steeles Avenue West, Toronto M2R 3T4, Ontario, Canada
| | - Matthew T. Balmer
- Sanofi Pasteur Limited,
1755 Steeles Avenue West, Toronto M2R 3T4, Ontario, Canada
| | - Derek J. Wilson
- Department of Chemistry, York
University, Toronto M3J 1P3, Ontario, Canada
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15
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A nexus of intrinsic dynamics underlies translocase priming. Structure 2021; 29:846-858.e7. [PMID: 33852897 DOI: 10.1016/j.str.2021.03.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 03/06/2021] [Accepted: 03/25/2021] [Indexed: 11/22/2022]
Abstract
The cytoplasmic ATPase SecA and the membrane-embedded SecYEG channel assemble to form the Sec translocase. How this interaction primes and catalytically activates the translocase remains unclear. We show that priming exploits a nexus of intrinsic dynamics in SecA. Using atomistic simulations, smFRET, and HDX-MS, we reveal multiple dynamic islands that cross-talk with domain and quaternary motions. These dynamic elements are functionally important and conserved. Central to the nexus is a slender stem through which rotation of the preprotein clamp of SecA is biased by ATPase domain motions between open and closed clamping states. An H-bonded framework covering most of SecA enables multi-tier dynamics and conformational alterations with minimal energy input. As a result, cognate ligands select preexisting conformations and alter local dynamics to regulate catalytic activity and clamp motions. These events prime the translocase for high-affinity reception of non-folded preprotein clients. Dynamics nexuses are likely universal and essential in multi-liganded proteins.
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16
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Yu K, Niu M, Wang H, Li Y, Wu Z, Zhang B, Haroutunian V, Peng J. Global Profiling of Lysine Accessibility to Evaluate Protein Structure Changes in Alzheimer's Disease. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2021; 32:936-945. [PMID: 33683887 PMCID: PMC8255072 DOI: 10.1021/jasms.0c00450] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The linear sequence of amino acids in a protein folds into a 3D structure to execute protein activity and function, but it is still challenging to profile the 3D structure at the proteome scale. Here, we present a method of native protein tandem mass tag (TMT) profiling of Lys accessibility and its application to investigate structural alterations in human brain specimens of Alzheimer's disease (AD). In this method, proteins are extracted under a native condition, labeled by TMT reagents, followed by trypsin digestion and peptide analysis using two-dimensional liquid chromatography and tandem mass spectrometry (LC/LC-MS/MS). The method quantifies Lys labeling efficiency to evaluate its accessibility on the protein surface, which may be affected by protein conformations, protein modifications, and/or other molecular interactions. We systematically optimized the amount of TMT reagents, reaction time, and temperature and then analyzed protein samples under multiple conditions, including different labeling time (5 and 30 min), heat treatment, AD and normal human cases. The experiment profiled 15370 TMT-labeled peptides in 4475 proteins. As expected, the heat treatment led to extensive changes in protein conformations, with 17% of the detected proteome displaying differential labeling. Compared to the normal controls, AD brain showed different Lys accessibility of tau and RNA splicing complexes, which are the hallmarks of AD pathology, as well as proteins involved in transcription, mitochondrial, and synaptic functions. To eliminate the possibility that the observed differential Lys labeling was caused by protein level change, the whole proteome was quantified with standard TMT-LC/LC-MS/MS for normalization. Thus, this native protein TMT method enables the proteome-wide measurement of Lys accessibility, representing a straightforward strategy to explore protein structure in any biological system.
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Affiliation(s)
- Kaiwen Yu
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Mingming Niu
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Hong Wang
- Center for Proteomics and Metabolomics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Yuxin Li
- Center for Proteomics and Metabolomics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Zhiping Wu
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
| | - Bin Zhang
- Department of Genetics and Genomic Sciences, Icahn Institute of Genomics and Multi-scale Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Vahram Haroutunian
- Departments of Psychiatry and Neuroscience, The Alzheimer’s Disease Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA; Mental Illness Research, Education and Clinical Center (MIRECC), James J Peters VA Medical Center, Bronx, NY 10468, USA
| | - Junmin Peng
- Departments of Structural Biology and Developmental Neurobiology, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
- Center for Proteomics and Metabolomics, St. Jude Children’s Research Hospital, Memphis, TN 38105, USA
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17
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Gopi S, Lukose B, Naganathan AN. Diverse Native Ensembles Dictate the Differential Functional Responses of Nuclear Receptor Ligand-Binding Domains. J Phys Chem B 2021; 125:3546-3555. [PMID: 33818099 DOI: 10.1021/acs.jpcb.1c00972] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Native states of folded proteins are characterized by a large ensemble of conformations whose relative populations and interconversion dynamics determine the functional output. This is more apparent in transcription factors that have evolved to be inherently sensitive to small perturbations, thus fine-tuning gene expression. To explore the extent to which such functional features are imprinted on the folding landscape of transcription factor ligand-binding domains (LBDs), we characterize paralogous LBDs of the nuclear receptor (NR) family employing an energetically detailed and ensemble-based Ising-like statistical mechanical model. We find that the native ensembles of the LBDs from glucocorticoid receptor, PPAγ, and thyroid hormone receptor display a remarkable diversity in the width of the native wells, the number and nature of partially structured states, and hence the degree of conformational order. Monte Carlo simulations employing the full state representation of the ensemble highlight that many of the functional conformations coexist in equilibrium, whose relative populations are sensitive to both temperature and the strength of ligand binding. Allosteric modulation of the degree of structure at a coregulator binding site on ligand binding is shown to arise via a redistribution of populations in the native ensembles of glucocorticoid and PPAγ LBDs. Our results illustrate how functional requirements can drive the evolution of conformationally diverse native ensembles in paralogs.
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Affiliation(s)
- Soundhararajan Gopi
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Bincy Lukose
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
| | - Athi N Naganathan
- Department of Biotechnology, Bhupat & Jyoti Mehta School of Biosciences, Indian Institute of Technology Madras, Chennai 600036, India
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18
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Engen JR, Botzanowski T, Peterle D, Georgescauld F, Wales TE. Developments in Hydrogen/Deuterium Exchange Mass Spectrometry. Anal Chem 2020; 93:567-582. [DOI: 10.1021/acs.analchem.0c04281] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- John R. Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Thomas Botzanowski
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Daniele Peterle
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Florian Georgescauld
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Thomas E. Wales
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
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19
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Medina E, Villalobos P, Hamilton GL, Komives EA, Sanabria H, Ramírez-Sarmiento CA, Babul J. Intrinsically Disordered Regions of the DNA-Binding Domain of Human FoxP1 Facilitate Domain Swapping. J Mol Biol 2020; 432:5411-5429. [PMID: 32735805 PMCID: PMC7663421 DOI: 10.1016/j.jmb.2020.07.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 07/21/2020] [Accepted: 07/22/2020] [Indexed: 01/01/2023]
Abstract
Forkhead box P (FoxP) proteins are unique transcription factors that spatiotemporally regulate gene expression by tethering two chromosome loci together via functional domain-swapped dimers formed through their DNA-binding domains. Further, the differential kinetics on this dimerization mechanism underlie an intricate gene regulation network at physiological conditions. Nonetheless, poor understanding of the structural dynamics and steps of the association process impedes to link the functional domain swapping to human-associated diseases. Here, we have characterized the DNA-binding domain of human FoxP1 by integrating single-molecule Förster resonance energy transfer and hydrogen-deuterium exchange mass spectrometry data with molecular dynamics simulations. Our results confirm the formation of a previously postulated domain-swapped (DS) FoxP1 dimer in solution and reveal the presence of highly populated, heterogeneous, and locally disordered dimeric intermediates along the dimer dissociation pathway. The unique features of FoxP1 provide a glimpse of how intrinsically disordered regions can facilitate domain swapping oligomerization and other tightly regulated association mechanisms relevant in biological processes.
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Affiliation(s)
- Exequiel Medina
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Casilla 653, Santiago 7800003, Chile
| | - Pablo Villalobos
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Casilla 653, Santiago 7800003, Chile
| | - George L Hamilton
- Department of Physics & Astronomy, Clemson University, Clemson, SC 29634, USA
| | - Elizabeth A Komives
- Department of Chemistry & Biochemistry, University of California San Diego, La Jolla, CA, USA
| | - Hugo Sanabria
- Department of Physics & Astronomy, Clemson University, Clemson, SC 29634, USA.
| | - César A Ramírez-Sarmiento
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile; Millennium Institute for Integrative Biology (iBio), Santiago, Chile.
| | - Jorge Babul
- Departamento de Biología, Facultad de Ciencias, Universidad de Chile, Las Palmeras 3425, Casilla 653, Santiago 7800003, Chile.
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20
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Kammari R, Topp EM. Effects of Secondary Structure on Solid-State Hydrogen–Deuterium Exchange in Model α-Helix and β-Sheet Peptides. Mol Pharm 2020; 17:3501-3512. [DOI: 10.1021/acs.molpharmaceut.0c00521] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Rajashekar Kammari
- Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
| | - Elizabeth M. Topp
- Department of Industrial and Physical Pharmacy, College of Pharmacy, Purdue University, 575 Stadium Mall Drive, West Lafayette, Indiana 47907, United States
- National Institute for Bioprocessing Research and Training, Belfield, Blackrock, Co., Dublin A94 X099, Ireland
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21
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Receptor-binding hydrogen–deuterium exchange mass spectrometry as an additional measurement of biosimilarity. JOURNAL OF PHARMACEUTICAL INVESTIGATION 2020. [DOI: 10.1007/s40005-019-00465-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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22
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Bradshaw RT, Marinelli F, Faraldo-Gómez JD, Forrest LR. Interpretation of HDX Data by Maximum-Entropy Reweighting of Simulated Structural Ensembles. Biophys J 2020; 118:1649-1664. [PMID: 32105651 PMCID: PMC7136279 DOI: 10.1016/j.bpj.2020.02.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 01/28/2020] [Accepted: 02/05/2020] [Indexed: 01/12/2023] Open
Abstract
Hydrogen-deuterium exchange combined with mass spectrometry (HDX-MS) is a widely applied biophysical technique that probes the structure and dynamics of biomolecules without the need for site-directed modifications or bio-orthogonal labels. The mechanistic interpretation of HDX data, however, is often qualitative and subjective, owing to a lack of quantitative methods to rigorously translate observed deuteration levels into atomistic structural information. To help address this problem, we have developed a methodology to generate structural ensembles that faithfully reproduce HDX-MS measurements. In this approach, an ensemble of protein conformations is first generated, typically using molecular dynamics simulations. A maximum-entropy bias is then applied post hoc to the resulting ensemble such that averaged peptide-deuteration levels, as predicted by an empirical model, agree with target values within a given level of uncertainty. We evaluate this approach, referred to as HDX ensemble reweighting (HDXer), for artificial target data reflecting the two major conformational states of a binding protein. We demonstrate that the information provided by HDX-MS experiments and by the model of exchange are sufficient to recover correctly weighted structural ensembles from simulations, even when the relevant conformations are rarely observed. Degrading the information content of the target data—e.g., by reducing sequence coverage, by averaging exchange levels over longer peptide segments, or by incorporating different sources of uncertainty—reduces the structural accuracy of the reweighted ensemble but still allows for useful insights into the distinctive structural features reflected by the target data. Finally, we describe a quantitative metric to rank candidate structural ensembles according to their correspondence with target data and illustrate the use of HDXer to describe changes in the conformational ensemble of the membrane protein LeuT. In summary, HDXer is designed to facilitate objective structural interpretations of HDX-MS data and to inform experimental approaches and further developments of theoretical exchange models.
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Affiliation(s)
- Richard T Bradshaw
- Computational Structural Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Fabrizio Marinelli
- Theoretical Molecular Biophysics Unit, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland
| | - José D Faraldo-Gómez
- Theoretical Molecular Biophysics Unit, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, Maryland.
| | - Lucy R Forrest
- Computational Structural Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland.
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23
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Galaz-Davison P, Molina JA, Silletti S, Komives EA, Knauer SH, Artsimovitch I, Ramírez-Sarmiento CA. Differential Local Stability Governs the Metamorphic Fold Switch of Bacterial Virulence Factor RfaH. Biophys J 2019; 118:96-104. [PMID: 31810657 DOI: 10.1016/j.bpj.2019.11.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 10/21/2019] [Accepted: 11/14/2019] [Indexed: 12/15/2022] Open
Abstract
RfaH, a two-domain protein from a universally conserved NusG/Spt5 family of regulators, is required for the transcription and translation of long virulence and conjugation operons in many Gram-negative bacterial pathogens. Escherichia coli RfaH action is controlled by a unique large-scale structural rearrangement triggered by recruitment to transcription elongation complexes through a specific DNA element. Upon recruitment, the C-terminal domain of RfaH refolds from an α-hairpin, which is bound to RNA polymerase binding site within the N-terminal domain, into an unbound β-barrel that interacts with the ribosome. Although structures of the autoinhibited (α-hairpin) and active (β-barrel) states and plausible refolding pathways have been reported, how this reversible switch is encoded within RfaH sequence and structure is poorly understood. Here, we combined hydrogen-deuterium exchange measurements by mass spectrometry and nuclear magnetic resonance with molecular dynamics to evaluate the differential local stability between both RfaH folds. Deuteron incorporation reveals that the tip of the C-terminal hairpin (residues 125-145) is stably folded in the autoinhibited state (∼20% deuteron incorporation), whereas the rest of this domain is highly flexible (>40% deuteron incorporation), and its flexibility only decreases in the β-folded state. Computationally predicted ΔG agree with these results by displaying similar anisotropic stability within the tip of the α-hairpin and on neighboring N-terminal domain residues. Remarkably, the β-folded state shows comparable structural flexibility than nonmetamorphic homologs. Our findings provide information critical for understanding the metamorphic behavior of RfaH and other chameleon proteins and for devising targeted strategies to combat bacterial infections.
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Affiliation(s)
- Pablo Galaz-Davison
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - José Alejandro Molina
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Steve Silletti
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California
| | - Elizabeth A Komives
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California
| | - Stefan H Knauer
- Lehrstuhl Biopolymere, Universität Bayreuth, Bayreuth, Germany
| | - Irina Artsimovitch
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, Ohio.
| | - César A Ramírez-Sarmiento
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.
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24
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Chen G, Fan M, Liu Y, Sun B, Liu M, Wu J, Li N, Guo M. Advances in MS Based Strategies for Probing Ligand-Target Interactions: Focus on Soft Ionization Mass Spectrometric Techniques. Front Chem 2019; 7:703. [PMID: 31709232 PMCID: PMC6819514 DOI: 10.3389/fchem.2019.00703] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 10/08/2019] [Indexed: 12/12/2022] Open
Abstract
The non-covalent interactions between small drug molecules and disease-related proteins (ligand-target interactions) mediate various pharmacological processes in the treatment of different diseases. The development of the analytical methods to assess those interactions, including binding sites, binding energies, stoichiometry and association-dissociation constants, could assist in clarifying the mechanisms of action, precise treatment of targeted diseases as well as the targeted drug discovery. For the last decades, mass spectrometry (MS) has been recognized as a powerful tool to study the non-covalent interactions of the ligand-target complexes with the characteristics of high sensitivity, high-resolution, and high-throughput. Soft ionization mass spectrometry, especially the electrospray mass spectrometry (ESI-MS) and matrix assisted laser desorption ionization mass spectrometry (MALDI-MS), could achieve the complete transformation of the target analytes into the gas phase, and subsequent detection of the small drug molecules and disease-related protein complexes, and has exerted great advantages for studying the drug ligands-protein targets interactions, even in case of identifying active components as drug ligands from crude extracts of medicinal plants. Despite of other analytical techniques for this purpose, such as the NMR and X-ray crystallography, this review highlights the principles, research hotspots and recent applications of the soft ionization mass spectrometry and its hyphenated techniques, including hydrogen-deuterium exchange mass spectrometry (HDX-MS), chemical cross-linking mass spectrometry (CX-MS), and ion mobility spectrometry mass spectrometry (IMS-MS), in the study of the non-covalent interactions between small drug molecules and disease-related proteins.
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Affiliation(s)
- Guilin Chen
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan, China
| | - Minxia Fan
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan, China
- Graduate University of Chinese Academy of Sciences, Beijing, China
| | - Ye Liu
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan, China
| | - Baoqing Sun
- State Key Laboratory of Respiratory Disease, National Clinical Center for Respiratory Diseases, Guangzhou Institute of Respiratory Diseases, First Affiliated Hospital, Guangzhou Medical University, Guangzhou, China
| | - Meixian Liu
- State Key Laboratory for Quality Research of Chinese Medicines, Macau University of Science and Technology, Taipa, Macau
| | - Jianlin Wu
- State Key Laboratory for Quality Research of Chinese Medicines, Macau University of Science and Technology, Taipa, Macau
| | - Na Li
- State Key Laboratory for Quality Research of Chinese Medicines, Macau University of Science and Technology, Taipa, Macau
| | - Mingquan Guo
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- Sino-Africa Joint Research Center, Chinese Academy of Sciences, Wuhan, China
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25
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Georgescauld F, Wales TE, Engen JR. Hydrogen deuterium exchange mass spectrometry applied to chaperones and chaperone-assisted protein folding. Expert Rev Proteomics 2019; 16:613-625. [DOI: 10.1080/14789450.2019.1633920] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Florian Georgescauld
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS, Laboratoire de Biologie Moléculaire et Cellulaire des Eucaryotes, UMR8226, Institut de Biologie Physico-Chimique, Paris, France
| | - Thomas E. Wales
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - John R. Engen
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
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26
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Markwick PRL, Peacock RB, Komives EA. Accurate Prediction of Amide Exchange in the Fast Limit Reveals Thrombin Allostery. Biophys J 2018; 116:49-56. [PMID: 30558884 DOI: 10.1016/j.bpj.2018.11.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 11/02/2018] [Accepted: 11/19/2018] [Indexed: 10/27/2022] Open
Abstract
Amide hydrogen/deuterium exchange mass spectrometry (HDXMS) of proteins has become extremely popular for identifying ligand-binding sites, protein-protein interactions, intrinsic disorder, and allosteric changes upon protein modification. Such phenomena are revealed when amide exchange is measured in the fast limit, that is, within a few minutes of exchange in deuterated buffer. The HDXMS data have a resolution of the length of peptides and are difficult to interpret because many different phenomena lead to changes in hydrogen/deuterium exchange. We present a quantitative analysis of accelerated molecular dynamics simulations that provides impressive agreement with peptide-length HDXMS data. Comparative analysis of thrombin and a single-point mutant reveals that the simulation analysis can distinguish the subtle differences in exchange due to mutation. In addition, the results provide a deeper understanding of the underlying changes in dynamics revealed by the HDXMS that extend far from the site of mutation.
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Affiliation(s)
- Phineus R L Markwick
- Department of Chemistry and Biochemistry, University of California, San Diego, San Diego, California
| | - Riley B Peacock
- Department of Chemistry and Biochemistry, University of California, San Diego, San Diego, California
| | - Elizabeth A Komives
- Department of Chemistry and Biochemistry, University of California, San Diego, San Diego, California.
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27
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Kaltashov IA. Mass spectrometry-based methods to study macromolecular higher order structure and interactions. Methods 2018; 144:1-2. [DOI: 10.1016/j.ymeth.2018.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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