1
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Yasin A, Mandato A, Hofmann L, Igbaria-Jaber Y, Shenberger Y, Gevorkyan-Airapetov L, Saxena S, Ruthstein S. The Dynamic Plasticity of P. aeruginosa CueR Copper Transcription Factor upon Cofactor and DNA Binding. Chembiochem 2024:e202400279. [PMID: 38776258 DOI: 10.1002/cbic.202400279] [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: 03/26/2024] [Revised: 05/17/2024] [Accepted: 05/22/2024] [Indexed: 05/24/2024]
Abstract
Bacteria use specialized proteins, like transcription factors, to rapidly control metal ion balance. CueR is a Gram-negative bacterial copper regulator. The structure of E. coli CueR complexed with Cu(I) and DNA was published, since then many studies have shed light on its function. However, P. aeruginosa CueR, which shows high sequence similarity to E. coli CueR, has been less studied. Here, we applied room-temperature electron paramagnetic resonance (EPR) measurements to explore changes in dynamics of P. aeruginosa CueR in dependency of copper concentrations and interaction with two different DNA promoter regions. We showed that P. aeruginosa CueR is less dynamic than the E. coli CueR protein and exhibits much higher sensitivity to DNA binding as compared to its E. coli CueR homolog. Moreover, a difference in dynamical behavior was observed when P. aeruginosa CueR binds to the copZ2 DNA promoter sequence compared to the mexPQ-opmE promoter sequence. Such dynamical differences may affect the expression levels of CopZ2 and MexPQ-OpmE proteins in P. aeruginosa. Overall, such comparative measurements of protein-DNA complexes derived from different bacterial systems reveal insights about how structural and dynamical differences between two highly homologous proteins lead to quite different DNA sequence-recognition and mechanistic properties.
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Affiliation(s)
- Ameer Yasin
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel, 5290002
| | - Alysia Mandato
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260
| | - Lukas Hofmann
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel, 5290002
| | - Yasmin Igbaria-Jaber
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel, 5290002
| | - Yulia Shenberger
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel, 5290002
| | - Lada Gevorkyan-Airapetov
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel, 5290002
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260
| | - Sharon Ruthstein
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar-Ilan University, Ramat-Gan, Israel, 5290002
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2
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Hu Y, Liu B. The Copper Efflux Regulator (CueR). Subcell Biochem 2024; 104:17-31. [PMID: 38963481 DOI: 10.1007/978-3-031-58843-3_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
The copper efflux regulator (CueR) is a classical member of the MerR family of metalloregulators and is common in gram-negative bacteria. Through its C-terminal effector-binding domain, CueR senses cytoplasmic copper ions to regulate the transcription of genes contributing to copper homeostasis, an essential process for survival of all cells. In this chapter, we review the regulatory roles of CueR in the model organism Escherichia coli and the mechanisms for CueR in copper binding, DNA recognition, and interplay with RNA polymerase in regulating transcription. In light of biochemical and structural analyses, we provide molecular details for how CueR represses transcription in the absence of copper ions, how copper ions mediate CueR conformational change to form holo CueR, and how CueR bends and twists promoter DNA to activate transcription. We also characterize the functional domains and key residues involved in these processes. Since CueR is a representative member of the MerR family, elucidating its regulatory mechanisms could help to understand the CueR-like regulators in other organisms and facilitate the understanding of other metalloregulators in the same family.
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Affiliation(s)
- Yangbo Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan, China.
| | - Bin Liu
- Section of Transcription & Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN, USA.
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3
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Bogetti X, Saxena S. Integrating Electron Paramagnetic Resonance Spectroscopy and Computational Modeling to Measure Protein Structure and Dynamics. Chempluschem 2024; 89:e202300506. [PMID: 37801003 DOI: 10.1002/cplu.202300506] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 10/07/2023]
Abstract
Electron paramagnetic resonance (EPR) has become a powerful probe of conformational heterogeneity and dynamics of biomolecules. In this Review, we discuss different computational modeling techniques that enrich the interpretation of EPR measurements of dynamics or distance restraints. A variety of spin labels are surveyed to provide a background for the discussion of modeling tools. Molecular dynamics (MD) simulations of models containing spin labels provide dynamical properties of biomolecules and their labels. These simulations can be used to predict EPR spectra, sample stable conformations and sample rotameric preferences of label sidechains. For molecular motions longer than milliseconds, enhanced sampling strategies and de novo prediction software incorporating or validated by EPR measurements are able to efficiently refine or predict protein conformations, respectively. To sample large-amplitude conformational transition, a coarse-grained or an atomistic weighted ensemble (WE) strategy can be guided with EPR insights. Looking forward, we anticipate an integrative strategy for efficient sampling of alternate conformations by de novo predictions, followed by validations by systematic EPR measurements and MD simulations. Continuous pathways between alternate states can be further sampled by WE-MD including all intermediate states.
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Affiliation(s)
- Xiaowei Bogetti
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA, 15260, USA
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA, 15260, USA
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4
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Schumann SL, Kotnig S, Kutin Y, Drosou M, Stratmann LM, Streltsova Y, Schnegg A, Pantazis DA, Clever GH, Kasanmascheff M. Structure and Flexibility of Copper-Modified DNA G-Quadruplexes Investigated by 19 F ENDOR Experiments at 34 GHz. Chemistry 2023; 29:e202302527. [PMID: 37602522 DOI: 10.1002/chem.202302527] [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: 08/03/2023] [Revised: 08/18/2023] [Accepted: 08/21/2023] [Indexed: 08/22/2023]
Abstract
DNA G-quadruplexes (GQs) are of great interest due to their involvement in crucial biological processes such as telomerase maintenance and gene expression. Furthermore, they are reported as catalytically active DNAzymes and building blocks in bio-nanotechnology. GQs exhibit remarkable structural diversity and conformational heterogeneity, necessitating precise and reliable tools to unravel their structure-function relationships. Here, we present insights into the structure and conformational flexibility of a unimolecular GQ with high spatial resolution via electron-nuclear double resonance (ENDOR) experiments combined with Cu(II) and fluorine labeling. These findings showcase the successful application of the 19 F-ENDOR methodology at 34 GHz, overcoming the limitations posed by the complexity and scarcity of higher-frequency spectrometers. Importantly, our approach retains both sensitivity and orientational resolution. This integrated study not only enhances our understanding of GQs but also expands the methodological toolbox for studying other macromolecules.
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Affiliation(s)
- Simon L Schumann
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 6, 44227, Dortmund, Germany
| | - Simon Kotnig
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 6, 44227, Dortmund, Germany
| | - Yury Kutin
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 6, 44227, Dortmund, Germany
| | - Maria Drosou
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Lukas M Stratmann
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 6, 44227, Dortmund, Germany
| | - Yana Streltsova
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 6, 44227, Dortmund, Germany
| | - Alexander Schnegg
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstraße 34-36, 45470, Mülheim an der Ruhr, Germany
| | - Dimitrios A Pantazis
- Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470, Mülheim an der Ruhr, Germany
| | - Guido H Clever
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 6, 44227, Dortmund, Germany
| | - Müge Kasanmascheff
- Department of Chemistry and Chemical Biology, TU Dortmund University, Otto-Hahn-Strasse 6, 44227, Dortmund, Germany
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5
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Mandato A, Hasanbasri Z, Saxena S. Double Quantum Coherence ESR at Q-Band Enhances the Sensitivity of Distance Measurements at Submicromolar Concentrations. J Phys Chem Lett 2023; 14:8909-8915. [PMID: 37768093 PMCID: PMC10577775 DOI: 10.1021/acs.jpclett.3c02372] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Accepted: 09/22/2023] [Indexed: 09/29/2023]
Abstract
Recently, there have been remarkable improvements in pulsed ESR sensitivity, paving the way for broader applicability of ESR in the measurement of biological distance constraints, for instance, at physiological concentrations and in more complex systems. Nevertheless, submicromolar distance measurements with the commonly used nitroxide spin label take multiple days. Therefore, there remains a need for rapid and reliable methods of measuring distances between spins at nanomolar concentrations. In this work, we demonstrate the power of double quantum coherence (DQC) experiments at Q-band frequencies. With the help of short and intense pulses, we showcase DQC signals on nitroxide-labeled proteins with modulation depths close to 100%. We show that the deep dipolar modulations aid in the resolution of bimodal distance distributions. Finally, we establish that distance measurements with protein concentrations as low as 25 nM are feasible. This limit is approximately 4-fold lower than previously possible. We anticipate that nanomolar concentration measurements will lead to further advancements in the use of ESR, especially in cellular contexts.
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Affiliation(s)
- Alysia Mandato
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
| | - Zikri Hasanbasri
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15213, United States
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6
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Shenberger Y, Gevorkyan-Airapetov L, Hirsch M, Hofmann L, Ruthstein S. An in-cell spin-labelling methodology provides structural information on cytoplasmic proteins in bacteria. Chem Commun (Camb) 2023; 59:10524-10527. [PMID: 37563959 DOI: 10.1039/d3cc03047d] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
EPR in-cell spin-labeling was applied to CueR in E. coli. The methodology employed a Cu(II)-NTA complexed with dHis. High resolved in-cell distance distributions were obtained revealing minor differences between in vitro and in-cell data. This methodology allows study of structural changes of any protein in-cell, independent of size or cellular system.
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Affiliation(s)
- Yulia Shenberger
- Department of Chemistry, Faculty of Exact Sciences and Institute of Nanotechnology and Advanced Materials, Bar Ilan university, 5290002, Israel.
| | - Lada Gevorkyan-Airapetov
- Department of Chemistry, Faculty of Exact Sciences and Institute of Nanotechnology and Advanced Materials, Bar Ilan university, 5290002, Israel.
| | - Melanie Hirsch
- Department of Chemistry, Faculty of Exact Sciences and Institute of Nanotechnology and Advanced Materials, Bar Ilan university, 5290002, Israel.
| | - Lukas Hofmann
- Department of Chemistry, Faculty of Exact Sciences and Institute of Nanotechnology and Advanced Materials, Bar Ilan university, 5290002, Israel.
| | - Sharon Ruthstein
- Department of Chemistry, Faculty of Exact Sciences and Institute of Nanotechnology and Advanced Materials, Bar Ilan university, 5290002, Israel.
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7
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Wort JL, Ackermann K, Giannoulis A, Bode BE. Enhanced sensitivity for pulse dipolar EPR spectroscopy using variable-time RIDME. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 352:107460. [PMID: 37167826 DOI: 10.1016/j.jmr.2023.107460] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 04/03/2023] [Accepted: 04/19/2023] [Indexed: 05/13/2023]
Abstract
Pulse dipolar EPR spectroscopy (PDS) measurements are an important complementary tool in structural biology and are increasingly applied to macromolecular assemblies implicated in human health and disease at physiological concentrations. This requires ever higher sensitivity, and recent advances have driven PDS measurements into the mid-nanomolar concentration regime, though optimization and acquisition of such measurements remains experimentally demanding and time expensive. One important consideration is that constant-time acquisition represents a hard limit for measurement sensitivity, depending on the maximum measured distance. Determining this distance a priori has been facilitated by machine-learning structure prediction (AlphaFold2 and RoseTTAFold) but is often confounded by non-representative behaviour in frozen solution that may mandate multiple rounds of optimization and acquisition. Herein, we endeavour to simultaneously enhance sensitivity and streamline PDS measurement optimization to one-step by benchmarking a variable-time acquisition RIDME experiment applied to CuII-nitroxide and CuII-CuII model systems. Results demonstrate marked sensitivity improvements of both 5- and 6-pulse variable-time RIDME of between 2- and 5-fold over the constant-time analogues.
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Affiliation(s)
- Joshua L Wort
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland
| | - Katrin Ackermann
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland
| | - Angeliki Giannoulis
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland
| | - Bela E Bode
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland.
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8
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Xiao Y, Chen L, Teng K, Ma J, Xiang S, Jiang L, Liu G, Yang B, Fang J. Potential roles of the rhizospheric bacterial community in assisting Miscanthus floridulus in remediating multi-metal(loid)s contaminated soils. ENVIRONMENTAL RESEARCH 2023; 227:115749. [PMID: 36965787 DOI: 10.1016/j.envres.2023.115749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 02/23/2023] [Accepted: 03/22/2023] [Indexed: 05/08/2023]
Abstract
Phytoremediation technology is an important approach applied to heavy metal remediation, and how to improve its remediation efficiency is the key. In this study, we compared the rhizospheric bacterial communities and metals contents in Miscanthus floridulus (M. floridulus) of four towns, including Huayuan Town (HY), Longtan Town (LT), Maoer Village (ME), and Minle Town (ML) around the lead-zinc mining area in Huayuan County, China. The roles of rhizospheric bacterial communities in assisting the phytoremediation of M. floridulus were explored. It was found that the compositions of the rhizospheric bacterial community of M. floridulus differed in four regions, but majority of them were heavy metal-resistant bacteria that could promote plant growth. Results of bioconcentration factors showed the enrichment of Cu, Zn, and Pb by M. floridulus in these four regions were significantly different. The Zn enrichment capacity of ML was the strongest for Cu and stronger than LT and ME for Pb. The enrichment capacity of LT and ML was stronger than HY and ME. These bacteria may influence the different heavy metals uptake of M. floridulus by altering the soil physiochemical properties (e.g., soil peroxidase, pH and moisture content). In addition, co-occurrence network analysis also showed that LT and ML had higher network stability and complexity than HY and ME. Functional prediction analysis of the rhizospheric bacterial community showed that genes related to protein synthesis (e.g., zinc-binding alcohol dehydrogenase/oxidoreductase, Dtx R family transcriptional regulators and ACC deaminase) also contributed to phytoremediation in various ways. This study provides theoretical guidance for selecting suitable microorganisms to assist in the phytoremediation of heavy metals.
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Affiliation(s)
- Yunhua Xiao
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China
| | - Liang Chen
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China
| | - Kai Teng
- Hunan Tobacco Science Institute, Changsha, 410004, China
| | - Jingjing Ma
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China
| | - Sha Xiang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China
| | - Lihong Jiang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China
| | - Gang Liu
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China
| | - Bo Yang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China.
| | - Jun Fang
- College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, China.
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9
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Casto J, Bogetti X, Hunter HR, Hasanbasri Z, Saxena S. "Store-bought is fine": Sensitivity considerations using shaped pulses for DEER measurements on Cu(II) labels. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 349:107413. [PMID: 36867974 DOI: 10.1016/j.jmr.2023.107413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 01/27/2023] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
The narrow excitation bandwidth of monochromic pulses is a sensitivity limitation for pulsed dipolar spectroscopy on Cu(II)-based measurements. In response, frequency-swept pulses with large excitation bandwidths have been adopted to probe a greater range of the EPR spectrum. However, much of the work utilizing frequency-swept pulses in Cu(II) distance measurements has been carried out on home-built spectrometers and equipment. Herein, we carry out systematic Cu(II) based distance measurements to demonstrate the capability of chirp pulses on commercial instrumentation. More importantly we delineate sensitivity considerations under acquisition schemes that are necessary for robust distance measurements using Cu(II) labels for proteins. We show that a 200 MHz sweeping bandwidth chirp pulse can improve the sensitivity of long-range distance measurements by factors of three to four. The sensitivity of short-range distances only increases slightly due to special considerations for the chirp pulse duration relative to the period length of the modulated dipolar signal. Enhancements in sensitivity also dramatically reduce measurement collection times enabling rapid collection of orientationally averaged Cu(II) distance measurements in under two hours.
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Affiliation(s)
- Joshua Casto
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Xiaowei Bogetti
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Hannah R Hunter
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Zikri Hasanbasri
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States.
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10
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Ackermann K, Khazaipoul S, Wort JL, Sobczak AIS, Mkami HE, Stewart AJ, Bode BE. Investigating Native Metal Ion Binding Sites in Mammalian Histidine-Rich Glycoprotein. J Am Chem Soc 2023; 145:8064-8072. [PMID: 37001144 PMCID: PMC10103162 DOI: 10.1021/jacs.3c00587] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
Abstract
Mammalian histidine-rich glycoprotein (HRG) is a highly versatile and abundant blood plasma glycoprotein with a diverse range of ligands that is involved in regulating many essential biological processes, including coagulation, cell adhesion, and angiogenesis. Despite its biomedical importance, structural information on the multi-domain protein is sparse, not least due to intrinsically disordered regions that elude high-resolution structural characterization. Binding of divalent metal ions, particularly ZnII, to multiple sites within the HRG protein is of critical functional importance and exerts a regulatory role. However, characterization of the ZnII binding sites of HRG is a challenge; their number and composition as well as their affinities and stoichiometries of binding are currently not fully understood. In this study, we explored modern electron paramagnetic resonance (EPR) spectroscopy methods supported by protein secondary and tertiary structure prediction to assemble a holistic picture of native HRG and its interaction with metal ions. To the best of our knowledge, this is the first time that this suite of EPR techniques has been applied to count and characterize endogenous metal ion binding sites in a native mammalian protein of unknown structure.
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Affiliation(s)
- Katrin Ackermann
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
- Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
| | - Siavash Khazaipoul
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
- Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
- School of Medicine, University of St Andrews, North Haugh, St Andrews KY16 9TF, Scotland
| | - Joshua L. Wort
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
- Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
| | - Amélie I. S. Sobczak
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
- Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
- School of Medicine, University of St Andrews, North Haugh, St Andrews KY16 9TF, Scotland
| | - Hassane El Mkami
- Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
- School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews KY16 9SS, Scotland
| | - Alan J. Stewart
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
- Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
- School of Medicine, University of St Andrews, North Haugh, St Andrews KY16 9TF, Scotland
| | - Bela E. Bode
- EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
- Biomedical Sciences Research Complex, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
- Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland
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11
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Hasanbasri Z, Moriglioni NA, Saxena S. Efficient sampling of molecular orientations for Cu(II)-based DEER on protein labels. Phys Chem Chem Phys 2023; 25:13275-13288. [PMID: 36939213 DOI: 10.1039/d3cp00404j] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/17/2023]
Abstract
Combining rigid Cu(II) labels and pulsed-EPR techniques enables distance constraint measurements that are incisive probes of protein structure and dynamics. However, the labels can lead to a dipolar signal that is biased by the relative orientation of the two spins, which is typically unknown a priori in a bilabeled protein. This effect, dubbed orientational selectivity, becomes a bottleneck in measuring distances. This phenomenon also applies to other pulsed-EPR techniques that probe electron-nucleus interactions. In this work, we dissect orientational selectivity by generating an in silico sample of Cu(II)-labeled proteins to evaluate pulse excitation in the context of double electron-electron resonance (DEER) at Q-band frequencies. This approach enables the observation of the contribution of each protein orientation to the dipolar signal, which provides direct insights into optimizing acquisition schemes to mitigate orientational effects. Furthermore, we incorporate the excitation profile of realistic pulses to identify the excited spins. With this method, we show that rectangular pulses, despite their imperfect inversion capability, can sample similar spin orientations as other sophisticated pulses with the same bandwidth. Additionally, we reveal that the efficiency of exciting spin-pairs in DEER depends on the frequency offset of two pulses used in the experiment and the relative orientation of the two spins. Therefore, we systematically examine the frequency offset of the two pulses used in this double resonance experiment to determine the optimal frequency offset for optimal distance measurements. This procedure leads to a protocol where two measurements are sufficient to acquire orientational-independent DEER at Q-band. Notably, this procedure is feasible with any commercial pulsed-EPR spectrometer. Furthermore, we experimentally validate the computational results using DEER experiments on two different proteins. Finally, we show that increasing the amplitude of the rectangular pulse can increase the efficiency of DEER experiments by almost threefold. Overall, this work provides an attractive new approach for analyzing pulsed-EPR spectroscopy to obtain microscopic nuances that cannot be easily discerned from analytical or numerical calculations.
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Affiliation(s)
- Zikri Hasanbasri
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.
| | | | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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12
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Schwartz R, Ruthstein S, Major DT. Copper coordination states affect the flexibility of copper Metallochaperone Atox1: Insights from molecular dynamics simulations. Protein Sci 2022; 31:e4464. [PMID: 36208051 PMCID: PMC9667823 DOI: 10.1002/pro.4464] [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: 05/19/2022] [Revised: 09/15/2022] [Accepted: 10/04/2022] [Indexed: 12/13/2022]
Abstract
Copper is an essential element in nature but in excess, it is toxic to the living cell. The human metallochaperone Atox1 participates in copper homeostasis and is responsible for copper transmission. In a previous multiscale simulation study, we noticed a change in the coordination state of the Cu(I) ion, from 4 bound cysteine residues to 3, in agreement with earlier studies. Here, we perform and analyze classical molecular dynamic simulations of various coordination states: 2, 3, and 4. The main observation is an increase in protein flexibility as a result of a decrease in the coordination state. In addition, we identified several populated conformations that correlate well with double electron-electron resonance distance distributions or an X-ray structure of Cu(I)-bound Atox1. We suggest that the increased flexibility might benefit the process of ion transmission between interacting proteins. Further experiments can scrutinize this hypothesis and shed additional light on the mechanism of action of Atox1.
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Affiliation(s)
- Renana Schwartz
- Department of Chemistry and Institute for Nanotechnology and Advanced MaterialsBar‐Ilan UniversityRamat‐GanIsrael
| | - Sharon Ruthstein
- Department of Chemistry and Institute for Nanotechnology and Advanced MaterialsBar‐Ilan UniversityRamat‐GanIsrael
| | - Dan Thomas Major
- Department of Chemistry and Institute for Nanotechnology and Advanced MaterialsBar‐Ilan UniversityRamat‐GanIsrael
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13
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Hofmann L, Mandato A, Saxena S, Ruthstein S. The use of EPR spectroscopy to study transcription mechanisms. Biophys Rev 2022; 14:1141-1159. [PMID: 36345280 PMCID: PMC9636360 DOI: 10.1007/s12551-022-01004-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 09/26/2022] [Indexed: 02/08/2023] Open
Abstract
Electron paramagnetic resonance (EPR) spectroscopy has become a promising structural biology tool to resolve complex and dynamic biological mechanisms in-vitro and in-cell. Here, we focus on the advantages of continuous wave (CW) and pulsed EPR distance measurements to resolve transcription processes and protein-DNA interaction. The wide range of spin-labeling approaches that can be used to follow structural changes in both protein and DNA render EPR a powerful method to study protein-DNA interactions and structure-function relationships in other macromolecular complexes. EPR-derived data goes well beyond static structural information and thus serves as the method of choice if dynamic insight is needed. Herein, we describe the conceptual details of the theory and the methodology and illustrate the use of EPR to study the protein-DNA interaction of the copper-sensitive transcription factor, CueR.
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Affiliation(s)
- L. Hofmann
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat-Gan, Israel
| | - A. Mandato
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA USA
| | - S. Saxena
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA USA
| | - S. Ruthstein
- Department of Chemistry and the Institute of Nanotechnology and Advanced Materials, Bar Ilan University, Ramat-Gan, Israel
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14
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Hofmann L, Ruthstein S. EPR Spectroscopy Provides New Insights into Complex Biological Reaction Mechanisms. J Phys Chem B 2022; 126:7486-7494. [PMID: 36137278 PMCID: PMC9549461 DOI: 10.1021/acs.jpcb.2c05235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
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In the last 20 years, the use of electron paramagnetic
resonance
(EPR) has made a pronounced and lasting impact in the field of structural
biology. The advantage of EPR spectroscopy over other structural techniques
is its ability to target even minor conformational changes in any
biomolecule or macromolecular complex, independent of its size or
complexity, or whether it is in solution or in the cell during a biological
or chemical reaction. Here, we focus on the use of EPR spectroscopy
to study transmembrane transport and transcription mechanisms. We
discuss experimental and analytical concerns when referring to studies
of two biological reaction mechanisms, namely, transfer of copper
ions by the human copper transporter hCtr1 and the mechanism of action
of the Escherichia coli copper-dependent
transcription factor CueR. Last, we elaborate on future avenues in
the field of EPR structural biology.
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Affiliation(s)
- Lukas Hofmann
- Department of Chemistry and the Institute of Nanotechnology & Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Sharon Ruthstein
- Department of Chemistry and the Institute of Nanotechnology & Advanced Materials, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
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15
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Bogetti X, Hasanbasri Z, Hunter HR, Saxena S. An optimal acquisition scheme for Q-band EPR distance measurements using Cu 2+-based protein labels. Phys Chem Chem Phys 2022; 24:14727-14739. [PMID: 35574729 DOI: 10.1039/d2cp01032a] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Recent advances in site-directed Cu2+ labeling of proteins and nucleic acids have added an attractive new methodology to measure the structure-function relationship in biomolecules. Despite the promise, accessing the higher sensitivity of Q-band Double Electron Electron Resonance (DEER) has been challenging for Cu2+ labels designed for proteins. Q-band DEER experiments on this label typically require many measurements at different magnetic fields, since the pulses can excite only a few orientations at a given magnetic field. Herein, we analyze such orientational effects through simulations and show that three DEER measurements, at strategically selected magnetic fields, are generally sufficient to acquire an orientational-averaged DEER time trace for this spin label at Q-band. The modeling results are experimentally verified on Cu2+ labeled human glutathione S-transferase (hGSTA1-1). The DEER distance distribution measured at the Q-band shows good agreement with the distance distribution sampled by molecular dynamics (MD) simulations and X-band experiments. The concordance of MD sampled distances and experimentally measured distances adds growing evidence that MD simulations can accurately predict distances for the Cu2+ labels, which remains a key bottleneck for the commonly used nitroxide label. In all, this minimal collection scheme reduces data collection time by as much as six-fold and is generally applicable to many octahedrally coordinated Cu2+ systems. Furthermore, the concepts presented here may be applied to other metals and pulsed EPR experiments.
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Affiliation(s)
- Xiaowei Bogetti
- Department of Chemistry, University of Pittsburgh, PA 15260, USA.
| | - Zikri Hasanbasri
- Department of Chemistry, University of Pittsburgh, PA 15260, USA.
| | - Hannah R Hunter
- Department of Chemistry, University of Pittsburgh, PA 15260, USA.
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, PA 15260, USA.
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16
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Balogh RK, Gyurcsik B, Jensen M, Thulstrup PW, Köster U, Christensen NJ, Jensen ML, Hunyadi-Gulyás É, Hemmingsen L, Jancso A. Tying up a loose end: On the role of the C-terminal CCHHRAG fragment of the metalloregulator CueR. Chembiochem 2022; 23:e202200290. [PMID: 35714117 PMCID: PMC9542689 DOI: 10.1002/cbic.202200290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Indexed: 11/07/2022]
Abstract
The transcriptional regulator CueR is activated by the binding of CuI, AgI, or AuI to two cysteinates in a near‐linear fashion. The C‐terminal CCHHRAG sequence in Escherichia coli CueR present potential additional metal binding ligands and here we explore the effect of deleting this fragment on the binding of AgI to CueR. CD spectroscopic and ESI‐MS data indicate that the high AgI‐binding affinity of WT‐CueR is significantly reduced in Δ7C‐CueR.[111 Ag PAC spectroscopy demonstrates that the WT‐CueR metal site structure (AgS2) is conserved, but less populated in the truncated variant. Thus, the function of the C‐terminal fragment may be to stabilize the two‐coordinate metal site for cognate monovalent metal ions. In a broader perspective this is an example of residues beyond the second coordination sphere affecting metal site physicochemical properties while leaving the structure unperturbed.
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Affiliation(s)
- Ria K Balogh
- University of Szeged: Szegedi Tudomanyegyetem, Department of Inorganic and Analytical Chemistry, HUNGARY
| | - Béla Gyurcsik
- University of Szeged: Szegedi Tudomanyegyetem, Department of Inorganic and Analytical Chemistry, HUNGARY
| | - Mikael Jensen
- Technical University of Denmark: Danmarks Tekniske Universitet, Hevesy Laboratory, Center for Nuclear Technologies, DENMARK
| | - Peter W Thulstrup
- University of Copenhagen: Kobenhavns Universitet, Department of Chemistry, DENMARK
| | - Ulli Köster
- Institut Laue-Langevin, Institut Laue-Langevin, FRANCE
| | - Niels Johan Christensen
- University of Copenhagen: Kobenhavns Universitet, Department of Chemistry, Faculty of Science, DENMARK
| | - Marianne L Jensen
- Niels Bohr Instituttet: Kobenhavns Universitet Niels Bohr Instituttet, Niels Bohr Institute, DENMARK
| | - Éva Hunyadi-Gulyás
- Biological Research Centre, Szeged, Laboratory of Proteomics Research, HUNGARY
| | - Lars Hemmingsen
- University of Copenhagen: Kobenhavns Universitet, Department of Chemistry, DENMARK
| | - Attila Jancso
- University of Szeged, Department of Inorganic and Analytical Chemistry, Dóm tér 7., 6720, Szeged, HUNGARY
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17
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Yakobov I, Mandato A, Hofmann L, Singewald K, Shenberger Y, Gevorkyan‐Airapetov L, Saxena S, Ruthstein S. Allostery‐driven changes in dynamics regulate the activation of bacterial copper transcription factor. Protein Sci 2022; 31:e4309. [PMID: 35481642 PMCID: PMC9004249 DOI: 10.1002/pro.4309] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/25/2022] [Accepted: 03/29/2022] [Indexed: 12/27/2022]
Abstract
Metalloregulators bind and respond to metal ions by regulating the transcription of metal homeostasis genes. Copper efflux regulator (CueR) is a copper‐responsive metalloregulator that is found in numerous Gram‐negative bacteria. Upon Cu(I) coordination, CueR initiates transcription by bending the bound DNA promoter regions facilitating interaction with RNA polymerase. The structure of Escherichia coli CueR in presence of DNA and metal ion has been reported using X‐ray crystallography and cryo‐EM, providing information about the mechanism of action. However, the specific role of copper in controlling this transcription mechanism remains elusive. Herein, we use room temperature electron paramagnetic resonance (EPR) experiments to follow allosterically driven dynamical changes in E. coli CueR induced by Cu(I) binding. We suggest that more than one Cu(I) ion binds per CueR monomer, leading to changes in site‐specific dynamics at the Cu(I) binding domain and at the distant DNA binding site. Interestingly, Cu(I) binding leads to an increase in dynamics about 27 Å away at the DNA binding domain. These changes in the dynamics of the DNA binding domain are important for exact coordination with the DNA. Thus, Cu(I) binding is critical to initiate a series of conformational changes that regulate and initiate gene transcription.
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Affiliation(s)
- Idan Yakobov
- Department of Chemistry and the Institute of Nanotechnology & Advanced Materials, Faculty of exact sciences Bar Ilan University Ramat‐Gan Israel
| | - Alysia Mandato
- Department of Chemistry University of Pittsburgh Pittsburgh Pennsylvania USA
| | - Lukas Hofmann
- Department of Chemistry and the Institute of Nanotechnology & Advanced Materials, Faculty of exact sciences Bar Ilan University Ramat‐Gan Israel
| | - Kevin Singewald
- Department of Chemistry University of Pittsburgh Pittsburgh Pennsylvania USA
| | - Yulia Shenberger
- Department of Chemistry and the Institute of Nanotechnology & Advanced Materials, Faculty of exact sciences Bar Ilan University Ramat‐Gan Israel
| | - Lada Gevorkyan‐Airapetov
- Department of Chemistry and the Institute of Nanotechnology & Advanced Materials, Faculty of exact sciences Bar Ilan University Ramat‐Gan Israel
| | - Sunil Saxena
- Department of Chemistry University of Pittsburgh Pittsburgh Pennsylvania USA
| | - Sharon Ruthstein
- Department of Chemistry and the Institute of Nanotechnology & Advanced Materials, Faculty of exact sciences Bar Ilan University Ramat‐Gan Israel
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