1
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Galazzo L, Meier G, Januliene D, Parey K, De Vecchis D, Striednig B, Hilbi H, Schäfer LV, Kuprov I, Moeller A, Bordignon E, Seeger MA. The ABC transporter MsbA adopts the wide inward-open conformation in E. coli cells. SCIENCE ADVANCES 2022; 8:eabn6845. [PMID: 36223470 PMCID: PMC9555771 DOI: 10.1126/sciadv.abn6845] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 08/24/2022] [Indexed: 05/28/2023]
Abstract
Membrane proteins are currently investigated after detergent extraction from native cellular membranes and reconstitution into artificial liposomes or nanodiscs, thereby removing them from their physiological environment. However, to truly understand the biophysical properties of membrane proteins in a physiological environment, they must be investigated within living cells. Here, we used a spin-labeled nanobody to interrogate the conformational cycle of the ABC transporter MsbA by double electron-electron resonance. Unexpectedly, the wide inward-open conformation of MsbA, commonly considered a nonphysiological state, was found to be prominently populated in Escherichia coli cells. Molecular dynamics simulations revealed that extensive lateral portal opening is essential to provide access of its large natural substrate core lipid A to the binding cavity. Our work paves the way to investigate the conformational landscape of membrane proteins in cells.
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Affiliation(s)
- Laura Galazzo
- Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44801 Bochum, Germany
- Department of Physical Chemistry, University of Geneva, 1211 Geneva, Switzerland
| | - Gianmarco Meier
- Institute of Medical Microbiology, University of Zurich, 8006 Zurich, Switzerland
| | - Dovile Januliene
- Department of Structural Biology, Osnabrück University, 49076 Osnabrück, Germany
| | - Kristian Parey
- Department of Structural Biology, Osnabrück University, 49076 Osnabrück, Germany
| | - Dario De Vecchis
- Center for Theoretical Chemistry, Ruhr University Bochum, 44801 Bochum, Germany
| | - Bianca Striednig
- Institute of Medical Microbiology, University of Zurich, 8006 Zurich, Switzerland
| | - Hubert Hilbi
- Institute of Medical Microbiology, University of Zurich, 8006 Zurich, Switzerland
| | - Lars V. Schäfer
- Center for Theoretical Chemistry, Ruhr University Bochum, 44801 Bochum, Germany
| | - Ilya Kuprov
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
| | - Arne Moeller
- Department of Structural Biology, Osnabrück University, 49076 Osnabrück, Germany
| | - Enrica Bordignon
- Faculty of Chemistry and Biochemistry, Ruhr University Bochum, 44801 Bochum, Germany
- Department of Physical Chemistry, University of Geneva, 1211 Geneva, Switzerland
| | - Markus A. Seeger
- Institute of Medical Microbiology, University of Zurich, 8006 Zurich, Switzerland
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2
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Structural insights into the catalytic cycle of a bacterial multidrug ABC efflux pump. J Mol Biol 2022; 434:167541. [DOI: 10.1016/j.jmb.2022.167541] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/02/2022] [Accepted: 03/09/2022] [Indexed: 12/19/2022]
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3
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Puthenveetil R, Christenson ET, Vinogradova O. New Horizons in Structural Biology of Membrane Proteins: Experimental Evaluation of the Role of Conformational Dynamics and Intrinsic Flexibility. MEMBRANES 2022; 12:227. [PMID: 35207148 PMCID: PMC8877495 DOI: 10.3390/membranes12020227] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 02/13/2022] [Accepted: 02/14/2022] [Indexed: 02/08/2023]
Abstract
A plethora of membrane proteins are found along the cell surface and on the convoluted labyrinth of membranes surrounding organelles. Since the advent of various structural biology techniques, a sub-population of these proteins has become accessible to investigation at near-atomic resolutions. The predominant bona fide methods for structure solution, X-ray crystallography and cryo-EM, provide high resolution in three-dimensional space at the cost of neglecting protein motions through time. Though structures provide various rigid snapshots, only an amorphous mechanistic understanding can be inferred from interpolations between these different static states. In this review, we discuss various techniques that have been utilized in observing dynamic conformational intermediaries that remain elusive from rigid structures. More specifically we discuss the application of structural techniques such as NMR, cryo-EM and X-ray crystallography in studying protein dynamics along with complementation by conformational trapping by specific binders such as antibodies. We finally showcase the strength of various biophysical techniques including FRET, EPR and computational approaches using a multitude of succinct examples from GPCRs, transporters and ion channels.
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Affiliation(s)
- Robbins Puthenveetil
- Section on Structural and Chemical Biology of Membrane Proteins, Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, 35A Convent Dr., Bethesda, MD 20892, USA
| | | | - Olga Vinogradova
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, CT 06269, USA
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4
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MsbA: an ABC transporter paradigm. Biochem Soc Trans 2021; 49:2917-2927. [PMID: 34821931 DOI: 10.1042/bst20211030] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 10/27/2021] [Accepted: 11/03/2021] [Indexed: 12/27/2022]
Abstract
ATP-binding cassette (ABC) transporters play an important role in various cellular processes. They display a similar architecture and share a mechanism which couples ATP hydrolysis to substrate transport. However, in the light of current data and recent experimental progress, this protein superfamily appears as multifaceted as their broad substrate range. Among the prokaryotic ABC transporters, MsbA can serve as a paradigm for research in this field. It is located in the inner membrane of Gram-negative bacteria and functions as a floppase for the lipopolysaccharide (LPS) precursor core-LPS, which is involved in the biogenesis of the bacterial outer membrane. While MsbA shows high similarity to eukaryotic ABC transporters, its expression in Gram-negative bacteria makes it conveniently accessible for many experimental approaches from spectroscopy to 3D structure determination. As an essential protein for bacterial membrane integrity, MsbA has also become an attractive target for the development of novel antibiotics. Furthermore, it serves as a model for multidrug efflux pumps. Here we provide an overview of recent findings and their relevance to the field, highlight the potential of methods such as solid-state NMR and EPR spectroscopy and provide a perspective for future work.
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5
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Frozen motion: how cryo-EM changes the way we look at ABC transporters. Trends Biochem Sci 2021; 47:136-148. [PMID: 34930672 DOI: 10.1016/j.tibs.2021.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 11/29/2021] [Accepted: 11/29/2021] [Indexed: 12/18/2022]
Abstract
ATP-binding cassette (ABC) transporters are widely present molecular machines that transfer substrates across the cell membrane. ABC transporters are involved in numerous physiological processes and are often clinical targets. Structural biology is fundamental to obtain the molecular details underlying ABC transporter function and suggest approaches to modulate it. Until recently, X-ray crystallography has been the only method capable of providing high-resolution structures of ABC transporters. However, modern cryo-electron microscopy (cryo-EM) opens entirely new ways of studying these dynamic membrane proteins. Cryo-EM enables analyses of targets that resist X-ray crystallography, challenging multicomponent complexes, and the exploration of conformational dynamics. These unique capacities have turned cryo-EM into the dominant technique for structural studies of membrane proteins, including ABC transporters.
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6
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Bartels K, Lasitza‐Male T, Hofmann H, Löw C. Single-Molecule FRET of Membrane Transport Proteins. Chembiochem 2021; 22:2657-2671. [PMID: 33945656 PMCID: PMC8453700 DOI: 10.1002/cbic.202100106] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 05/03/2021] [Indexed: 12/31/2022]
Abstract
Uncovering the structure and function of biomolecules is a fundamental goal in structural biology. Membrane-embedded transport proteins are ubiquitous in all kingdoms of life. Despite structural flexibility, their mechanisms are typically studied by ensemble biochemical methods or by static high-resolution structures, which complicate a detailed understanding of their dynamics. Here, we review the recent progress of single molecule Förster Resonance Energy Transfer (smFRET) in determining mechanisms and timescales of substrate transport across membranes. These studies do not only demonstrate the versatility and suitability of state-of-the-art smFRET tools for studying membrane transport proteins but they also highlight the importance of membrane mimicking environments in preserving the function of these proteins. The current achievements advance our understanding of transport mechanisms and have the potential to facilitate future progress in drug design.
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Affiliation(s)
- Kim Bartels
- Centre for Structural Systems Biology (CSSB)DESY and European Molecular Biology Laboratory HamburgNotkestrasse 8522607HamburgGermany
| | - Tanya Lasitza‐Male
- Department of Structural BiologyWeizmann Institute of ScienceHerzl St. 2347610001RehovotIsrael
| | - Hagen Hofmann
- Department of Structural BiologyWeizmann Institute of ScienceHerzl St. 2347610001RehovotIsrael
| | - Christian Löw
- Centre for Structural Systems Biology (CSSB)DESY and European Molecular Biology Laboratory HamburgNotkestrasse 8522607HamburgGermany
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7
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Jubair N, Rajagopal M, Chinnappan S, Abdullah NB, Fatima A. Review on the Antibacterial Mechanism of Plant-Derived Compounds against Multidrug-Resistant Bacteria (MDR). EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2021; 2021:3663315. [PMID: 34447454 PMCID: PMC8384518 DOI: 10.1155/2021/3663315] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 06/27/2021] [Accepted: 07/24/2021] [Indexed: 02/06/2023]
Abstract
Microbial resistance has progressed rapidly and is becoming the leading cause of death globally. The spread of antibiotic-resistant microorganisms has been a significant threat to the successful therapy against microbial infections. Scientists have become more concerned about the possibility of a return to the pre-antibiotic era. Thus, searching for alternatives to fight microorganisms has become a necessity. Some bacteria are naturally resistant to antibiotics, while others acquire resistance mainly by the misuse of antibiotics and the emergence of new resistant variants through mutation. Since ancient times, plants represent the leading source of drugs and alternative medicine for fighting against diseases. Plants are rich sources of valuable secondary metabolites, such as alkaloids, quinones, tannins, terpenoids, flavonoids, and polyphenols. Many studies focus on plant secondary metabolites as a potential source for antibiotic discovery. They have the required structural properties and can act by different mechanisms. This review analyses the antibiotic resistance strategies produced by multidrug-resistant bacteria and explores the phytochemicals from different classes with documented antimicrobial action against resistant bacteria, either alone or in combination with traditional antibiotics.
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Affiliation(s)
- Najwan Jubair
- Faculty of Pharmaceutical Sciences, UCSI University, Kuala Lumpur 56000, Malaysia
| | - Mogana Rajagopal
- Faculty of Pharmaceutical Sciences, UCSI University, Kuala Lumpur 56000, Malaysia
| | - Sasikala Chinnappan
- Faculty of Pharmaceutical Sciences, UCSI University, Kuala Lumpur 56000, Malaysia
| | | | - Ayesha Fatima
- Beykoz Institute of Life Sciences and Biotechnology, Bezmialem Vakif University, Istanbul, Turkey
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8
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Jodaitis L, van Oene T, Martens C. Assessing the Role of Lipids in the Molecular Mechanism of Membrane Proteins. Int J Mol Sci 2021; 22:7267. [PMID: 34298884 PMCID: PMC8306737 DOI: 10.3390/ijms22147267] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 06/30/2021] [Accepted: 07/01/2021] [Indexed: 02/06/2023] Open
Abstract
Membrane proteins have evolved to work optimally within the complex environment of the biological membrane. Consequently, interactions with surrounding lipids are part of their molecular mechanism. Yet, the identification of lipid-protein interactions and the assessment of their molecular role is an experimental challenge. Recently, biophysical approaches have emerged that are compatible with the study of membrane proteins in an environment closer to the biological membrane. These novel approaches revealed specific mechanisms of regulation of membrane protein function. Lipids have been shown to play a role in oligomerization, conformational transitions or allosteric coupling. In this review, we summarize the recent biophysical approaches, or combination thereof, that allow to decipher the role of lipid-protein interactions in the mechanism of membrane proteins.
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Affiliation(s)
| | | | - Chloé Martens
- Center for Structural Biology and Bioinformatics, Université Libre de Bruxelles, 1050 Brussels, Belgium; (L.J.); (T.v.O.)
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9
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Sikkema HR, Poolman B. In silico method for selecting residue pairs for single-molecule microscopy and spectroscopy. Sci Rep 2021; 11:5756. [PMID: 33707507 PMCID: PMC7952708 DOI: 10.1038/s41598-021-85003-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/17/2021] [Indexed: 02/07/2023] Open
Abstract
Obtaining (dynamic) structure related information on proteins is key for understanding their function. Methods as single-molecule Förster Resonance Energy Transfer (smFRET) and Electron Paramagnetic Resonance (EPR) that measure distances between labeled residues to obtain dynamic information rely on selection of suitable residue pairs for chemical modification. Selection of pairs of amino acids, that show sufficient distance changes upon activity of the protein, can be a tedious process. Here we present an in silico approach that makes use of two or more structures (or structure models) to filter suitable residue pairs for FRET or EPR from all possible pairs within the protein. We apply the method for the study of the conformational dynamics of the substrate-binding domain of the osmoregulatory ATP-Binding Cassette transporter OpuA. This method speeds up the process of designing mutants, and because of its systematic nature, the chances of missing promising candidates are reduced.
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Affiliation(s)
- Hendrik R Sikkema
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands
| | - Bert Poolman
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, The Netherlands.
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10
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Carusela MF, Miguel Rubi J. Computational Model for Membrane Transporters. Potential Implications for Cancer. Front Cell Dev Biol 2021; 9:642665. [PMID: 33693005 PMCID: PMC7937797 DOI: 10.3389/fcell.2021.642665] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 02/04/2021] [Indexed: 01/13/2023] Open
Abstract
To explain the increased transport of nutrients and metabolites and to control the movement of drug molecules through the transporters to the cancer cells, it is important to understand the exact mechanism of their structure and activity, as well as their biological and physical characteristics. We propose a computational model that reproduces the functionality of membrane transporters by quantifying the flow of substrates through the cell membrane. The model identifies the force induced by conformational changes of the transporter due to hydrolysis of ATP, in ABC transporters, or by an electrochemical gradient of ions, in secondary transporters. The transport rate is computed by averaging the velocity generated by the force along the paths followed by the substrates. The results obtained are in accordance with the experiments. The model provides an overall framework for analyzing the membrane transport proteins that regulate the flows of ions, nutrients and other molecules across the cell membranes, and their activities.
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Affiliation(s)
- María Florencia Carusela
- Instituto de Ciencias, Universidad Nacional de General Sarmiento, Buenos Aires, Argentina
- National Scientific and Technical Research Council, Buenos Aires, Argentina
| | - J. Miguel Rubi
- Departament de Física de la Matèria Condensada, Universitat de Barcelona, Barcelona, Spain
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11
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Tassis K, Vietrov R, de Koning M, de Boer M, Gouridis G, Cordes T. Single-molecule studies of conformational states and dynamics in the ABC importer OpuA. FEBS Lett 2021; 595:717-734. [PMID: 33314056 DOI: 10.1002/1873-3468.14026] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 11/02/2020] [Accepted: 11/20/2020] [Indexed: 12/30/2022]
Abstract
The current model of active transport via ABC importers is mostly based on structural, biochemical and genetic data. We here establish single-molecule Förster resonance energy transfer (smFRET) assays to monitor the conformational states and heterogeneity of the osmoregulatory type I ABC importer OpuA from Lactococcus lactis. We present data probing both intradomain distances that elucidate conformational changes within the substrate-binding domain (SBD) OpuAC, and interdomain distances between SBDs or transmembrane domains. Using this methodology, we studied ligand-binding mechanisms, as well as ATP and glycine betaine dependences of conformational changes. Our work expands the scope of smFRET investigations towards a class of so far unstudied ABC importers, and paves the way for a full understanding of their transport cycle in the future.
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Affiliation(s)
- Konstantinos Tassis
- Molecular Microscopy Research Group, Zernike Institute for Advanced Materials, University of Groningen, The Netherlands
| | - Ruslan Vietrov
- Molecular Microscopy Research Group, Zernike Institute for Advanced Materials, University of Groningen, The Netherlands.,Department of Biochemistry, Groningen Biomolecular Science and Biotechnology Institute, Netherlands Proteomics Centre & Zernike Institute for Advanced Materials, University of Groningen, The Netherlands
| | - Matthijs de Koning
- Molecular Microscopy Research Group, Zernike Institute for Advanced Materials, University of Groningen, The Netherlands
| | - Marijn de Boer
- Molecular Microscopy Research Group, Zernike Institute for Advanced Materials, University of Groningen, The Netherlands
| | - Giorgos Gouridis
- Molecular Microscopy Research Group, Zernike Institute for Advanced Materials, University of Groningen, The Netherlands.,Laboratory of Molecular Bacteriology, Department of Microbiology and Immunology, Rega Institute for Medical Research, KU Leuven, Belgium.,Structural Biology Division, Institute of Molecular Biology and Biotechnology (IMBB-FORTH), Heraklion-Crete, Greece
| | - Thorben Cordes
- Molecular Microscopy Research Group, Zernike Institute for Advanced Materials, University of Groningen, The Netherlands.,Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians Universität München, Martinsried, Germany
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12
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Bordignon E, Seeger MA, Galazzo L, Meier G. From in vitro towards in situ: structure-based investigation of ABC exporters by electron paramagnetic resonance spectroscopy. FEBS Lett 2020; 594:3839-3856. [PMID: 33219535 DOI: 10.1002/1873-3468.14004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 10/30/2020] [Accepted: 11/15/2020] [Indexed: 12/12/2022]
Abstract
ATP-binding cassette (ABC) exporters have been studied now for more than four decades, and recent structural investigation has produced a large number of protein database entries. Yet, important questions about how ABC exporters function at the molecular level remain debated, such as which are the molecular recognition hotspots and the allosteric couplings dynamically regulating the communication between the catalytic cycle and the export of substrates. This conundrum mainly arises from technical limitations confining all research to in vitro analysis of ABC transporters in detergent solutions or embedded in membrane-mimicking environments. Therefore, a largely unanswered question is how ABC exporters operate in situ, namely in the native membrane context of a metabolically active cell. This review focuses on novel mechanistic insights into type I ABC exporters gained through a unique combination of structure determination, biochemical characterization, generation of conformation-specific nanobodies/sybodies and double electron-electron resonance.
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Affiliation(s)
- Enrica Bordignon
- Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Markus A Seeger
- Institute of Medical Microbiology, University of Zurich, Switzerland
| | - Laura Galazzo
- Faculty of Chemistry and Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Gianmarco Meier
- Institute of Medical Microbiology, University of Zurich, Switzerland
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13
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Gouridis G, Hetzert B, Kiosze-Becker K, de Boer M, Heinemann H, Nürenberg-Goloub E, Cordes T, Tampé R. ABCE1 Controls Ribosome Recycling by an Asymmetric Dynamic Conformational Equilibrium. Cell Rep 2020; 28:723-734.e6. [PMID: 31315050 PMCID: PMC6656783 DOI: 10.1016/j.celrep.2019.06.052] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 02/04/2019] [Accepted: 06/14/2019] [Indexed: 11/04/2022] Open
Abstract
The twin-ATPase ABCE1 has a vital function in mRNA translation by recycling terminated or stalled ribosomes. As for other functionally distinct ATP-binding cassette (ABC) proteins, the mechanochemical coupling of ATP hydrolysis to conformational changes remains elusive. Here, we use an integrated biophysical approach allowing direct observation of conformational dynamics and ribosome association of ABCE1 at the single-molecule level. Our results from FRET experiments show that the current static two-state model of ABC proteins has to be expanded because the two ATP sites of ABCE1 are in dynamic equilibrium across three distinct conformational states: open, intermediate, and closed. The interaction of ABCE1 with ribosomes influences the conformational dynamics of both ATP sites asymmetrically and creates a complex network of conformational states. Our findings suggest a paradigm shift to redefine the understanding of the mechanochemical coupling in ABC proteins: from structure-based deterministic models to dynamic-based systems. Both ATP sites of ABCE1 are in an asymmetric conformational equilibrium Each ATP site can adopt three functionally distinct conformational states These equilibria shift during ribosome recycling depending on interaction partners ATP binding, but not hydrolysis, is required for ribosome splitting
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Affiliation(s)
- Giorgos Gouridis
- Molecular Microscopy Research Group, Zernike Institute for Advanced Material, University of Groningen, 9747 AG Groningen, the Netherlands; Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany; Department of Microbiology and Immunology, Rega Institute for Medical Research, Laboratory of Molecular Bacteriology, KU Leuven, 3000 Leuven, Belgium
| | - Bianca Hetzert
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt a.M., Germany
| | - Kristin Kiosze-Becker
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt a.M., Germany
| | - Marijn de Boer
- Molecular Microscopy Research Group, Zernike Institute for Advanced Material, University of Groningen, 9747 AG Groningen, the Netherlands
| | - Holger Heinemann
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt a.M., Germany
| | - Elina Nürenberg-Goloub
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt a.M., Germany
| | - Thorben Cordes
- Molecular Microscopy Research Group, Zernike Institute for Advanced Material, University of Groningen, 9747 AG Groningen, the Netherlands; Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany.
| | - Robert Tampé
- Institute of Biochemistry, Biocenter, Goethe University Frankfurt, 60438 Frankfurt a.M., Germany.
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14
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Szöllősi D, Chiba P, Szakacs G, Stockner T. Conversion of chemical to mechanical energy by the nucleotide binding domains of ABCB1. Sci Rep 2020; 10:2589. [PMID: 32054924 PMCID: PMC7018802 DOI: 10.1038/s41598-020-59403-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 01/27/2020] [Indexed: 01/13/2023] Open
Abstract
P-glycoprotein (ABCB1) is an important component of barrier tissues that extrudes a wide range of chemically unrelated compounds. ABCB1 consists of two transmembrane domains forming the substrate binding and translocation domain, and of two cytoplasmic nucleotide binding domains (NBDs) that provide the energy by binding and hydrolyzing ATP. We analyzed the mechanistic and energetic properties of the NBD dimer via molecular dynamics simulations. We find that MgATP stabilizes the NBD dimer through strong attractive forces by serving as an interaction hub. The irreversible ATP hydrolysis step converts the chemical energy stored in the phosphate bonds of ATP into potential energy. Following ATP hydrolysis, interactions between the NBDs and the ATP hydrolysis products MgADP + Pi remain strong, mainly because Mg2+ forms stabilizing interactions with ADP and Pi. Despite these stabilizing interactions MgADP + Pi are unable to hold the dimer together, which becomes separated by avid interactions of MgADP + Pi with water. ATP binding to the open NBDs and ATP hydrolysis in the closed NBD dimer represent two steps of energy input, each leading to the formation of a high energy state. Relaxation from these high energy states occurs through conformational changes that push ABCB1 through the transport cycle.
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Affiliation(s)
- Dániel Szöllősi
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstr. 13A, 1090, Vienna, Austria
| | - Peter Chiba
- Medical University of Vienna, Institute of Medical Chemistry, Center for Pathobiochemistry and Genetics, Waehringerstr. 10, 1090, Vienna, Austria
| | - Gergely Szakacs
- Medical University of Vienna, Institute of Cancer Research, Borschkegasse 8A, 1090, Vienna, Austria
| | - Thomas Stockner
- Medical University of Vienna, Center for Physiology and Pharmacology, Institute of Pharmacology, Waehringerstr. 13A, 1090, Vienna, Austria.
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15
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Camp T, Mehta K, Sligar SG, Zhang K. Molecular Orientation Determination in Nanodiscs at the Single-Molecule Level. Anal Chem 2020; 92:2229-2236. [PMID: 31851490 DOI: 10.1021/acs.analchem.9b04950] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The function of membrane-bound proteins often depends on their interactions with the lipid bilayer. Bulk absorption-based linear dichroism has been historically used to investigate molecular orientations in the phospholipid bilayer but cannot resolve the actual distribution of molecules embedded in the membrane and is often limited by a poor signal-to-noise ratio. Here, we present single-molecule orientation determination by fluorescence-detected linear dichroism visualization in Nanodisc grids or SOLVING, to determine the molecular orientation of molecules assembled into nanoscale lipid bilayers. We provide a proof-of-concept by using SOLVING to quantitate the orientation distribution of two commonly used fluorescent dyes, DiO and BODIPY, in 10 nm Nanodiscs. Besides confirming the mean orientation determined by bulk absorption measurement, SOLVING provides the actual distribution of orientations and promises to provide key molecular insights into the topology and interactions of multiprotein complexes, such as those observed in intracellular signal transduction.
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Affiliation(s)
- Tyler Camp
- Center for Biophysics and Quantitative Biology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Kritika Mehta
- Department of Biochemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Stephen G Sligar
- Department of Biochemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Center for Biophysics and Quantitative Biology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Department of Chemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States
| | - Kai Zhang
- Department of Biochemistry , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Center for Biophysics and Quantitative Biology , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Neuroscience Program , University of Illinois at Urbana-Champaign , Urbana , Illinois 61801 , United States.,Beckman Institute , University of Illinois at Urbana-Champaign 600 South Mathews Avenue , Urbana , Illinois 61801 , United States
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16
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Structural Kinetics of MsbA Investigated by Stopped-Flow Time-Resolved Small-Angle X-Ray Scattering. Structure 2019; 28:348-354.e3. [PMID: 31899087 DOI: 10.1016/j.str.2019.12.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Revised: 10/06/2019] [Accepted: 12/02/2019] [Indexed: 12/19/2022]
Abstract
Recent structures of full-length ATP-binding cassette (ABC) transporter MsbA in different states indicate large conformational changes during the reaction cycle that involve transient dimerization of its nucleotide-binding domains (NBDs). However, a detailed molecular understanding of the structural changes and associated kinetics of MsbA upon ATP binding and hydrolysis is still missing. Here, we employed time-resolved small-angle X-ray scattering, initiated by stopped-flow mixing, to investigate the kinetics and accompanying structural changes of NBD dimerization (upon ATP binding) and subsequent dissociation (upon ATP hydrolysis) in the context of isolated NBDs as well as full-length MsbA in lipid nanodiscs. Our data allowed us to structurally characterize the major states involved in the process and determine time constants for NBD dimerization and dissociation. In the full-length protein, these structural transitions occur on much faster time scales, indicating close-proximity effects and structural coupling of the transmembrane domains with the NBDs.
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17
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Mächtel R, Narducci A, Griffith DA, Cordes T, Orelle C. An integrated transport mechanism of the maltose ABC importer. Res Microbiol 2019; 170:321-337. [PMID: 31560984 PMCID: PMC6906923 DOI: 10.1016/j.resmic.2019.09.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Revised: 09/10/2019] [Accepted: 09/13/2019] [Indexed: 12/27/2022]
Abstract
ATP-binding cassette (ABC) transporters use the energy of ATP hydrolysis to transport a large diversity of molecules actively across biological membranes. A combination of biochemical, biophysical, and structural studies has established the maltose transporter MalFGK2 as one of the best characterized proteins of the ABC family. MalF and MalG are the transmembrane domains, and two MalKs form a homodimer of nucleotide-binding domains. A periplasmic maltose-binding protein (MalE) delivers maltose and other maltodextrins to the transporter, and triggers its ATPase activity. Substrate import occurs in a unidirectional manner by ATP-driven conformational changes in MalK2 that allow alternating access of the substrate-binding site in MalF to each side of the membrane. In this review, we present an integrated molecular mechanism of the transport process considering all currently available information. Furthermore, we summarize remaining inconsistencies and outline possible future routes to decipher the full mechanistic details of transport by MalEFGK2 complex and that of related importer systems.
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Affiliation(s)
- Rebecca Mächtel
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152 Planegg-Martinsried, Germany
| | - Alessandra Narducci
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152 Planegg-Martinsried, Germany
| | - Douglas A Griffith
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152 Planegg-Martinsried, Germany
| | - Thorben Cordes
- Physical and Synthetic Biology, Faculty of Biology, Ludwig-Maximilians-Universität München, Großhadernerstr. 2-4, 82152 Planegg-Martinsried, Germany.
| | - Cédric Orelle
- Université de Lyon, CNRS, UMR5086 "Molecular Microbiology and Structural Biochemistry", IBCP, 7 passage du Vercors, 69367 Lyon, France.
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18
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Padayatti PS, Lee SC, Stanfield RL, Wen PC, Tajkhorshid E, Wilson IA, Zhang Q. Structural Insights into the Lipid A Transport Pathway in MsbA. Structure 2019; 27:1114-1123.e3. [PMID: 31130486 PMCID: PMC6610721 DOI: 10.1016/j.str.2019.04.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 03/12/2019] [Accepted: 04/10/2019] [Indexed: 11/27/2022]
Abstract
MsbA is an essential ATP-binding cassette transporter in Gram-negative bacteria that transports lipid A and lipopolysaccharide from the cytoplasmic leaflet to the periplasmic leaflet of the inner membrane. Here we report the X-ray structure of MsbA from Salmonella typhimurium at 2.8-Å resolution in an inward-facing conformation after cocrystallization with lipid A and using a stabilizing facial amphiphile. The structure displays a large amplitude opening in the transmembrane portal, which is likely required for lipid A to pass from its site of synthesis into the protein-enclosed transport pathway. Putative lipid A density is observed further inside the transmembrane cavity, consistent with a trap and flip model. Additional electron density attributed to lipid A is observed near an outer surface cleft at the periplasmic ends of the transmembrane helices. These findings provide new structural insights into the lipid A transport pathway through comparative analysis with existing MsbA structures.
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Affiliation(s)
- Pius S Padayatti
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Sung Chang Lee
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Robyn L Stanfield
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Po-Chao Wen
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Emad Tajkhorshid
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, Department of Biochemistry, Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Ian A Wilson
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA; Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Qinghai Zhang
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
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19
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smFRET Probing Reveals Substrate-Dependent Conformational Dynamics of E. coli Multidrug MdfA. Biophys J 2019; 116:2296-2303. [PMID: 31146923 DOI: 10.1016/j.bpj.2019.04.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 04/10/2019] [Accepted: 04/23/2019] [Indexed: 11/21/2022] Open
Abstract
Bacterial multidrug-resistance transporters of the major facilitator superfamily are distinguished by their extraordinary ability to bind structurally diverse substrates, thus serving as a highly efficient tool to protect cells from multiple toxic substances present in their environment, including antibiotic drugs. However, details of the dynamic conformational changes of the transport cycle involved remain to be elucidated. Here, we used the single-molecule fluorescence resonance energy transfer technique to investigate the conformational behavior of the Escherichia coli multidrug transporter MdfA under conditions of different substrates, pH, and alkali metal ions. Our data show that different substrates exhibit distinct effects on both the conformational distribution and transition rate between two major conformations. Although the cationic substrate tetraphenylphosphonium favors the outward-facing conformation, it has less effect on the transition rate. In contrast, binding of the electroneutral substrate chloramphenicol tends to stabilize the inward-facing conformation and decreases the transition rate. Therefore, our study supports the notion that the MdfA transporter uses distinct mechanisms to transport electroneutral and cationic substrates.
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20
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Zhang XC, Zhang H. P-type ATPases use a domain-association mechanism to couple ATP hydrolysis to conformational change. BIOPHYSICS REPORTS 2019. [DOI: 10.1007/s41048-019-0087-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
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