1
|
Allen WJ, Corey RA, Watkins DW, Oliveira ASF, Hards K, Cook GM, Collinson I. Rate-limiting transport of positively charged arginine residues through the Sec-machinery is integral to the mechanism of protein secretion. eLife 2022; 11:e77586. [PMID: 35486093 PMCID: PMC9110029 DOI: 10.7554/elife.77586] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 04/29/2022] [Indexed: 11/24/2022] Open
Abstract
Transport of proteins across and into membranes is a fundamental biological process with the vast majority being conducted by the ubiquitous Sec machinery. In bacteria, this is usually achieved when the SecY-complex engages the cytosolic ATPase SecA (secretion) or translating ribosomes (insertion). Great strides have been made towards understanding the mechanism of protein translocation. Yet, important questions remain - notably, the nature of the individual steps that constitute transport, and how the proton-motive force (PMF) across the plasma membrane contributes. Here, we apply a recently developed high-resolution protein transport assay to explore these questions. We find that pre-protein transport is limited primarily by the diffusion of arginine residues across the membrane, particularly in the context of bulky hydrophobic sequences. This specific effect of arginine, caused by its positive charge, is mitigated for lysine which can be deprotonated and transported across the membrane in its neutral form. These observations have interesting implications for the mechanism of protein secretion, suggesting a simple mechanism through which the PMF can aid transport by enabling a 'proton ratchet', wherein re-protonation of exiting lysine residues prevents channel re-entry, biasing transport in the outward direction.
Collapse
Affiliation(s)
- William J Allen
- School of Biochemistry, University of Bristol, University WalkBristolUnited Kingdom
| | - Robin A Corey
- School of Biochemistry, University of Bristol, University WalkBristolUnited Kingdom
| | - Daniel W Watkins
- School of Biochemistry, University of Bristol, University WalkBristolUnited Kingdom
| | - A Sofia F Oliveira
- School of Biochemistry, University of Bristol, University WalkBristolUnited Kingdom
- School of Chemistry, University of Bristol, University WalkBristolUnited Kingdom
| | - Kiel Hards
- Department of Microbiology and Immunology, University of OtagoDunedinNew Zealand
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of OtagoDunedinNew Zealand
| | - Ian Collinson
- School of Biochemistry, University of Bristol, University WalkBristolUnited Kingdom
| |
Collapse
|
2
|
Corey RA, Ahdash Z, Shah A, Pyle E, Allen WJ, Fessl T, Lovett JE, Politis A, Collinson I. ATP-induced asymmetric pre-protein folding as a driver of protein translocation through the Sec machinery. eLife 2019; 8:41803. [PMID: 30601115 PMCID: PMC6335059 DOI: 10.7554/elife.41803] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 01/01/2019] [Indexed: 11/13/2022] Open
Abstract
Transport of proteins across membranes is a fundamental process, achieved in every cell by the 'Sec' translocon. In prokaryotes, SecYEG associates with the motor ATPase SecA to carry out translocation for pre-protein secretion. Previously, we proposed a Brownian ratchet model for transport, whereby the free energy of ATP-turnover favours the directional diffusion of the polypeptide (Allen et al., 2016). Here, we show that ATP enhances this process by modulating secondary structure formation within the translocating protein. A combination of molecular simulation with hydrogendeuterium-exchange mass spectrometry and electron paramagnetic resonance spectroscopy reveal an asymmetry across the membrane: ATP-induced conformational changes in the cytosolic cavity promote unfolded pre-protein structure, while the exterior cavity favours its formation. This ability to exploit structure within a pre-protein is an unexplored area of protein transport, which may apply to other protein transporters, such as those of the endoplasmic reticulum and mitochondria.
Collapse
Affiliation(s)
- Robin A Corey
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Zainab Ahdash
- Department of Chemistry, King's College London, London, United Kingdom
| | - Anokhi Shah
- SUPA School of Physics and Astronomy and BSRC, University of St Andrews, Scotland, United Kingdom
| | - Euan Pyle
- Department of Chemistry, King's College London, London, United Kingdom.,Department of Chemistry, Imperial College London, London, United Kingdom
| | - William J Allen
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Tomas Fessl
- University of South Bohemia in Ceske Budejovice, České Budějovice, Czech Republic
| | - Janet E Lovett
- SUPA School of Physics and Astronomy and BSRC, University of St Andrews, Scotland, United Kingdom
| | - Argyris Politis
- Department of Chemistry, King's College London, London, United Kingdom
| | - Ian Collinson
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| |
Collapse
|
3
|
Mizobata T, Kawata Y. The versatile mutational "repertoire" of Escherichia coli GroEL, a multidomain chaperonin nanomachine. Biophys Rev 2017; 10:631-640. [PMID: 29181744 DOI: 10.1007/s12551-017-0332-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 11/05/2017] [Indexed: 12/14/2022] Open
Abstract
The bacterial chaperonins are highly sophisticated molecular nanomachines, controlled by the hydrolysis of ATP to dynamically trap and remove from the environment unstable protein molecules that are susceptible to denaturation and aggregation. Chaperonins also act to assist in the refolding of these unstable proteins, providing a means by which these proteins may return in active form to the complex environment of the cell. The Escherichia coli GroE chaperonin system is one of the largest protein supramolecular complexes known, whose quaternary structure is required for segregating aggregation-prone proteins. Over the course of more than two decades of research on GroE, it has become accepted that GroE, more specifically the GroEL subunit, is a "high-tolerance" molecular system, capable of accommodating numerous mutations, while retaining its molecular integrity. In some cases, a given site of mutation was revealed to be absolutely required for GroEL function, providing hints regarding the network of signals and triggers that propel this unique system. In other instances, however, a mutation has produced a more delicate response, altering only part of, or in some cases, only a single facet of, the molecular mechanism, and these mutants have often provided invaluable hints on the extent of the complexity underlying chaperonin-assisted protein folding. In this review, we highlight some examples of the latter type of GroEL mutants which compose the unique "mutational repertoire" of GroEL and touch upon the important clues that each mutant provided to the overall effort to elucidate the details of GroE action.
Collapse
Affiliation(s)
- Tomohiro Mizobata
- Graduate School of Engineering and Graduate School of Medical Sciences, Tottori University, Tottori, 680-8552, Japan.
| | - Yasushi Kawata
- Graduate School of Engineering and Graduate School of Medical Sciences, Tottori University, Tottori, 680-8552, Japan.
| |
Collapse
|
4
|
|
5
|
Allen WJ, Corey RA, Oatley P, Sessions RB, Baldwin SA, Radford SE, Tuma R, Collinson I. Two-way communication between SecY and SecA suggests a Brownian ratchet mechanism for protein translocation. eLife 2016; 5. [PMID: 27183269 PMCID: PMC4907695 DOI: 10.7554/elife.15598] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 05/14/2016] [Indexed: 01/25/2023] Open
Abstract
The essential process of protein secretion is achieved by the ubiquitous Sec machinery. In prokaryotes, the drive for translocation comes from ATP hydrolysis by the cytosolic motor-protein SecA, in concert with the proton motive force (PMF). However, the mechanism through which ATP hydrolysis by SecA is coupled to directional movement through SecYEG is unclear. Here, we combine all-atom molecular dynamics (MD) simulations with single molecule FRET and biochemical assays. We show that ATP binding by SecA causes opening of the SecY-channel at long range, while substrates at the SecY-channel entrance feed back to regulate nucleotide exchange by SecA. This two-way communication suggests a new, unifying 'Brownian ratchet' mechanism, whereby ATP binding and hydrolysis bias the direction of polypeptide diffusion. The model represents a solution to the problem of transporting inherently variable substrates such as polypeptides, and may underlie mechanisms of other motors that translocate proteins and nucleic acids.
Collapse
Affiliation(s)
| | - Robin Adam Corey
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Peter Oatley
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.,School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | | | - Steve A Baldwin
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.,School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Sheena E Radford
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Roman Tuma
- Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, United Kingdom.,School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Ian Collinson
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| |
Collapse
|
6
|
Tran HT, Pham TV, Ngo HPT, Hong MK, Kim JG, Lee SH, Ahn YJ, Kang LW. Crystallization and preliminary X-ray crystallographic analysis of the XoGroEL chaperonin from Xanthomonas oryzae pv. oryzae. ACTA CRYSTALLOGRAPHICA SECTION F-STRUCTURAL BIOLOGY COMMUNICATIONS 2014; 70:604-7. [PMID: 24817719 DOI: 10.1107/s2053230x14006591] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 03/25/2014] [Indexed: 11/11/2022]
Abstract
Along with the co-chaperonin GroES, the chaperonin GroEL plays an essential role in enhancing protein folding or refolding and in protecting proteins against misfolding and aggregation in the cellular environment. The XoGroEL gene (XOO_4288) from Xanthomonas oryzae pv. oryzae was cloned and the protein was expressed, purified and crystallized. The purified XoGroEL protein was crystallized using the hanging-drop vapour-diffusion method and a crystal diffracted to a resolution of 3.4 Å. The crystal belonged to the orthorhombic space group P212121 with 14 monomers in the asymmetric unit, with a corresponding VM of 2.7 Å(3) Da(-1) and a solvent content of 54.5%.
Collapse
Affiliation(s)
- Huyen Thi Tran
- Department of Advanced Technology Fusion, Konkuk University, Hwayang dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Tan Viet Pham
- Department of Advanced Technology Fusion, Konkuk University, Hwayang dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Ho Phuong Thuy Ngo
- Department of Biological Sciences, Konkuk University, Hwayang dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Myoung Ki Hong
- Department of Biological Sciences, Konkuk University, Hwayang dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| | - Jeong Gu Kim
- Genomics Division, National Academy of Agricultural Science (NAAS), Rural Development Administration (RDA), Suwon 441-707, Republic of Korea
| | - Sang Hee Lee
- National Leading Research Laboratory, Department of Biological Sciences, Myongji University, 116 Myongjiro, Yongin, Gyeonggido 449-728, Republic of Korea
| | - Yeh Jin Ahn
- Department of Life Science, College of Natural Sciences, Sangmyung University, Seoul 110-743, Republic of Korea
| | - Lin Woo Kang
- Department of Biological Sciences, Konkuk University, Hwayang dong, Gwangjin-gu, Seoul 143-701, Republic of Korea
| |
Collapse
|
7
|
Xue W, Yang Y, Wang X, Liu H, Yao X. Computational study on the inhibitor binding mode and allosteric regulation mechanism in hepatitis C virus NS3/4A protein. PLoS One 2014; 9:e87077. [PMID: 24586263 PMCID: PMC3934852 DOI: 10.1371/journal.pone.0087077] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 12/16/2013] [Indexed: 01/17/2023] Open
Abstract
HCV NS3/4A protein is an attractive therapeutic target responsible for harboring serine protease and RNA helicase activities during the viral replication. Small molecules binding at the interface between the protease and helicase domains can stabilize the closed conformation of the protein and thus block the catalytic function of HCV NS3/4A protein via an allosteric regulation mechanism. But the detailed mechanism remains elusive. Here, we aimed to provide some insight into the inhibitor binding mode and allosteric regulation mechanism of HCV NS3/4A protein by using computational methods. Four simulation systems were investigated. They include: apo state of HCV NS3/4A protein, HCV NS3/4A protein in complex with an allosteric inhibitor and the truncated form of the above two systems. The molecular dynamics simulation results indicate HCV NS3/4A protein in complex with the allosteric inhibitor 4VA adopts a closed conformation (inactive state), while the truncated apo protein adopts an open conformation (active state). Further residue interaction network analysis suggests the communication of the domain-domain interface play an important role in the transition from closed to open conformation of HCV NS3/4A protein. However, the inhibitor stabilizes the closed conformation through interaction with several key residues from both the protease and helicase domains, including His57, Asp79, Asp81, Asp168, Met485, Cys525 and Asp527, which blocks the information communication between the functional domains interface. Finally, a dynamic model about the allosteric regulation and conformational changes of HCV NS3/4A protein was proposed and could provide fundamental insights into the allosteric mechanism of HCV NS3/4A protein function regulation and design of new potent inhibitors.
Collapse
Affiliation(s)
- Weiwei Xue
- State Key Laboratory of Applied Organic Chemistry, Department of Chemistry, Lanzhou University, Lanzhou, China
| | - Ying Yang
- Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xiaoting Wang
- State Key Laboratory of Applied Organic Chemistry, Department of Chemistry, Lanzhou University, Lanzhou, China
| | - Huanxiang Liu
- School of Pharmacy, Lanzhou University, Lanzhou, China
| | - Xiaojun Yao
- State Key Laboratory of Applied Organic Chemistry, Department of Chemistry, Lanzhou University, Lanzhou, China
- State Key Laboratory of Quality Research in Chinese Medicine, Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Taipa, Macau, China
| |
Collapse
|
8
|
Using simulations to provide the framework for experimental protein folding studies. Arch Biochem Biophys 2012; 531:128-35. [PMID: 23266569 DOI: 10.1016/j.abb.2012.12.015] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 12/10/2012] [Accepted: 12/14/2012] [Indexed: 12/27/2022]
Abstract
Molecular dynamics simulations are a powerful theoretical tool to model the protein folding process in atomistic details under realistic conditions. Combined with a number of experimental techniques, simulations provide a detailed picture of how a protein folds or unfolds in the presence of explicit solvent and other molecular species, such as cosolvents, osmolytes, cofactors, active binding partners or inert crowding agents. The denaturing effects of temperature, pressure and external mechanical forces can also be probed. Qualitative and quantitative agreement with experiment contributes to a comprehensive molecular picture of protein states along the folding/unfolding pathway. The variety of systems examined reveals key features of the protein folding process.
Collapse
|
9
|
Whitehouse S, Gold VAM, Robson A, Allen WJ, Sessions RB, Collinson I. Mobility of the SecA 2-helix-finger is not essential for polypeptide translocation via the SecYEG complex. ACTA ACUST UNITED AC 2012; 199:919-29. [PMID: 23209305 PMCID: PMC3518217 DOI: 10.1083/jcb.201205191] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Polypeptide translocation in bacteria, once underway, requires only one copy each of SecA and SecYEG and does not require the mobility of the SecA 2-helix-finger. The bacterial ATPase SecA and protein channel complex SecYEG form the core of an essential protein translocation machinery. The nature of the conformational changes induced by each stage of the hydrolytic cycle of ATP and how they are coupled to protein translocation are not well understood. The structure of the SecA–SecYEG complex revealed a 2-helix-finger (2HF) of SecA in an ideal position to contact the substrate protein and push it through the membrane. Surprisingly, immobilization of this finger at the edge of the protein channel had no effect on translocation, whereas its imposition inside the channel blocked transport. This analysis resolves the stoichiometry of the active complex, demonstrating that after the initiation process translocation requires only one copy each of SecA and SecYEG. The results also have important implications on the mechanism of energy transduction and the power stroke driving transport. Evidently, the 2HF is not a highly mobile transducing element of polypeptide translocation.
Collapse
Affiliation(s)
- Sarah Whitehouse
- School of Biochemistry, University of Bristol, Bristol BS8 1TD, England, UK
| | | | | | | | | | | |
Collapse
|