1
|
Gómez Borrego J, Torrent Burgas M. Structural assembly of the bacterial essential interactome. eLife 2024; 13:e94919. [PMID: 38226900 PMCID: PMC10863985 DOI: 10.7554/elife.94919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 12/22/2023] [Indexed: 01/17/2024] Open
Abstract
The study of protein interactions in living organisms is fundamental for understanding biological processes and central metabolic pathways. Yet, our knowledge of the bacterial interactome remains limited. Here, we combined gene deletion mutant analysis with deep-learning protein folding using AlphaFold2 to predict the core bacterial essential interactome. We predicted and modeled 1402 interactions between essential proteins in bacteria and generated 146 high-accuracy models. Our analysis reveals previously unknown details about the assembly mechanisms of these complexes, highlighting the importance of specific structural features in their stability and function. Our work provides a framework for predicting the essential interactomes of bacteria and highlight the potential of deep-learning algorithms in advancing our understanding of the complex biology of living organisms. Also, the results presented here offer a promising approach to identify novel antibiotic targets.
Collapse
Affiliation(s)
- Jordi Gómez Borrego
- Systems Biology of Infection Lab, Department of Biochemistry and Molecular Biology, Biosciences Faculty, Universitat Autònoma de BarcelonaCerdanyola del VallèsSpain
| | - Marc Torrent Burgas
- Systems Biology of Infection Lab, Department of Biochemistry and Molecular Biology, Biosciences Faculty, Universitat Autònoma de BarcelonaCerdanyola del VallèsSpain
| |
Collapse
|
2
|
Njenga R, Boele J, Öztürk Y, Koch HG. Coping with stress: How bacteria fine-tune protein synthesis and protein transport. J Biol Chem 2023; 299:105163. [PMID: 37586589 PMCID: PMC10502375 DOI: 10.1016/j.jbc.2023.105163] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/08/2023] [Accepted: 08/10/2023] [Indexed: 08/18/2023] Open
Abstract
Maintaining a functional proteome under different environmental conditions is challenging for every organism, in particular for unicellular organisms, such as bacteria. In order to cope with changing environments and stress conditions, bacteria depend on strictly coordinated proteostasis networks that control protein production, folding, trafficking, and degradation. Regulation of ribosome biogenesis and protein synthesis are cornerstones of this cellular adaptation in all domains of life, which is rationalized by the high energy demand of both processes and the increased resistance of translationally silent cells against internal or external poisons. Reduced protein synthesis ultimately also reduces the substrate load for protein transport systems, which are required for maintaining the periplasmic, inner, and outer membrane subproteomes. Consequences of impaired protein transport have been analyzed in several studies and generally induce a multifaceted response that includes the upregulation of chaperones and proteases and the simultaneous downregulation of protein synthesis. In contrast, generally less is known on how bacteria adjust the protein targeting and transport machineries to reduced protein synthesis, e.g., when cells encounter stress conditions or face nutrient deprivation. In the current review, which is mainly focused on studies using Escherichia coli as a model organism, we summarize basic concepts on how ribosome biogenesis and activity are regulated under stress conditions. In addition, we highlight some recent developments on how stress conditions directly impair protein targeting to the bacterial membrane. Finally, we describe mechanisms that allow bacteria to maintain the transport of stress-responsive proteins under conditions when the canonical protein targeting pathways are impaired.
Collapse
Affiliation(s)
- Robert Njenga
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany; Faculty of Biology, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Julian Boele
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Yavuz Öztürk
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany
| | - Hans-Georg Koch
- Faculty of Medicine, Institute for Biochemistry and Molecular Biology, ZBMZ, Albert-Ludwigs University Freiburg, Freiburg, Germany.
| |
Collapse
|
3
|
Weichselbaum E, Galimzyanov T, Batishchev OV, Akimov SA, Pohl P. Proton Migration on Top of Charged Membranes. Biomolecules 2023; 13:biom13020352. [PMID: 36830721 PMCID: PMC9953355 DOI: 10.3390/biom13020352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/23/2023] [Accepted: 02/07/2023] [Indexed: 02/15/2023] Open
Abstract
Proton relay between interfacial water molecules allows rapid two-dimensional diffusion. An energy barrier, ΔGr‡, opposes proton-surface-to-bulk release. The ΔGr‡-regulating mechanism thus far has remained unknown. Here, we explored the effect interfacial charges have on ΔGr‡'s enthalpic and entropic constituents, ΔGH‡ and ΔGS‡, respectively. A light flash illuminating a micrometer-sized membrane patch of a free-standing planar lipid bilayer released protons from an adsorbed hydrophobic caged compound. A lipid-anchored pH-sensitive dye reported protons' arrival at a distant membrane patch. Introducing net-negative charges to the bilayer doubled ΔGH‡, while positive net charges decreased ΔGH‡. The accompanying variations in ΔGS‡ compensated for the ΔGH‡ modifications so that ΔGr‡ was nearly constant. The increase in the entropic component of the barrier is most likely due to the lower number and strength of hydrogen bonds known to be formed by positively charged residues as compared to negatively charged moieties. The resulting high ΔGr‡ ensured interfacial proton diffusion for all measured membranes. The observation indicates that the variation in membrane surface charge alone is a poor regulator of proton traffic along the membrane surface.
Collapse
Affiliation(s)
- Ewald Weichselbaum
- Institute of Biophysics, Johannes Kepler University Linz, 4040 Linz, Austria
| | - Timur Galimzyanov
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow 119071, Russia
- Department of Theoretical Physics and Quantum Technologies, National University of Science and Technology “MISiS”, Moscow 119991, Russia
| | - Oleg V. Batishchev
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow 119071, Russia
| | - Sergey A. Akimov
- A.N. Frumkin Institute of Physical Chemistry and Electrochemistry, Russian Academy of Sciences, Moscow 119071, Russia
- Department of Theoretical Physics and Quantum Technologies, National University of Science and Technology “MISiS”, Moscow 119991, Russia
| | - Peter Pohl
- Institute of Biophysics, Johannes Kepler University Linz, 4040 Linz, Austria
- Correspondence:
| |
Collapse
|
4
|
Zhu Z, Wang S, Shan SO. Ribosome profiling reveals multiple roles of SecA in cotranslational protein export. Nat Commun 2022; 13:3393. [PMID: 35697696 PMCID: PMC9192764 DOI: 10.1038/s41467-022-31061-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 05/26/2022] [Indexed: 11/18/2022] Open
Abstract
SecA, an ATPase known to posttranslationally translocate secretory proteins across the bacterial plasma membrane, also binds ribosomes, but the role of SecA’s ribosome interaction has been unclear. Here, we used a combination of ribosome profiling methods to investigate the cotranslational actions of SecA. Our data reveal the widespread accumulation of large periplasmic loops of inner membrane proteins in the cytoplasm during their cotranslational translocation, which are specifically recognized and resolved by SecA in coordination with the proton motive force (PMF). Furthermore, SecA associates with 25% of secretory proteins with highly hydrophobic signal sequences at an early stage of translation and mediates their cotranslational transport. In contrast, the chaperone trigger factor (TF) delays SecA engagement on secretory proteins with weakly hydrophobic signal sequences, thus enforcing a posttranslational mode of their translocation. Our results elucidate the principles of SecA-driven cotranslational protein translocation and reveal a hierarchical network of protein export pathways in bacteria. Using a combination of ribosome profiling methods, Zhu et al. investigate the principles governing the cotranslational interaction of SecA with nascent proteins and reveal a hierarchical organization of protein export pathways in bacteria.
Collapse
Affiliation(s)
- Zikun Zhu
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA
| | - Shuai Wang
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.,Department of Molecular and Cellular Physiology, Stanford University, Stanford, CA, 94305, USA
| | - Shu-Ou Shan
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, USA.
| |
Collapse
|
5
|
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; 11:77586. [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] [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, Bristol, United Kingdom
| | - Robin A Corey
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
| | - Daniel W Watkins
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | | | - Kiel Hards
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Duneding, New Zealand
| | - Ian Collinson
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
| |
Collapse
|
6
|
Vazulka S, Schiavinato M, Wagenknecht M, Cserjan-Puschmann M, Striedner G. Interaction of Periplasmic Fab Production and Intracellular Redox Balance in Escherichia coli Affects Product Yield. ACS Synth Biol 2022; 11:820-834. [PMID: 35041397 PMCID: PMC8859853 DOI: 10.1021/acssynbio.1c00502] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Antibody fragments such as Fab's require the formation of disulfide bonds to achieve a proper folding state. During their recombinant, periplasmic expression in Escherichia coli, oxidative folding is mediated by the DsbA/DsbB system in concert with ubiquinone. Thereby, overexpression of Fab's is linked to the respiratory chain, which is not only immensely important for the cell's energy household but also known as a major source of reactive oxygen species. However, the effects of an increased oxidative folding demand and the consequently required electron flux via ubiquinone on the host cell have not been characterized so far. Here, we show that Fab expression in E. coli BL21(DE3) interfered with the intracellular redox balance, thereby negatively impacting host cell performance. Production of four different model Fab's in lab-scale fed-batch cultivations led to increased oxygen consumption rates and strong cell lysis. An RNA sequencing analysis revealed transcription activation of the oxidative stress-responsive soxS gene in the Fab-producing strains. We attributed this to the accumulation of intracellular superoxide, which was measured using flow cytometry. An exogenously supplemented ubiquinone analogue improved Fab yields up to 82%, indicating that partitioning of the quinone pool between aerobic respiration and oxidative folding limited ubiquinone availability and hence disulfide bond formation capacity. Combined, our results provide a more in-depth understanding of the profound effects that periplasmic Fab expression and in particular disulfide bond formation has on the host cell. Thereby, we show new possibilities to elaborate cell engineering and process strategies for improved host cell fitness and process outcome.
Collapse
Affiliation(s)
- Sophie Vazulka
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. Coli, Department of Biotechnology, Institute of Bioprocess Science and Engineering, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria
| | - Matteo Schiavinato
- Department of Biotechnology, Institute of Computational Biology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria
| | - Martin Wagenknecht
- Boehringer Ingelheim RCV GmbH & Co KG, Dr.-Boehringer-Gasse 5-11, 1120 Vienna, Austria
| | - Monika Cserjan-Puschmann
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. Coli, Department of Biotechnology, Institute of Bioprocess Science and Engineering, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria
| | - Gerald Striedner
- Christian Doppler Laboratory for Production of Next-Level Biopharmaceuticals in E. Coli, Department of Biotechnology, Institute of Bioprocess Science and Engineering, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria
| |
Collapse
|
7
|
Sobakinskaya E, Krobath H, Renger T, Müh F. Structural determinants of a permeation barrier of the SecYEG translocon in the active state. Phys Chem Chem Phys 2021; 23:25830-25840. [PMID: 34762087 PMCID: PMC8612361 DOI: 10.1039/d1cp02702f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 11/02/2021] [Indexed: 11/21/2022]
Abstract
The SecYEG translocon is a channel in bacteria, which provides a passage for secretory proteins across as well as integration of membrane proteins into the plasma membrane. The molecular mechanism, by which SecYEG manages protein transport while preventing water and ion leakage through the membrane, is still controversial. We employed molecular dynamics simulations to assess the contribution of the major structural elements - the plug and the pore ring (PR) - to the sealing of SecYEG in the active state, i.e., with a signal sequence helix occupying the lateral gate. We found, that the PR alone can provide a very tight seal for the wild-type translocon in the active state for both water and ions. Simulations of the mutant I403N, in which one of the PR-defining isoleucine residues is replaced with asparagine, suggest that hydrophobic interactions within the PR and between the PR and the plug are important for maintaining a tight conformation of the wild-type channel around the PR. Disruption of these interactions results in strong fluctuations of helix TM7 and water leakage of the translocon.
Collapse
Affiliation(s)
- Ekaterina Sobakinskaya
- Institute for Theoretical Physics, Johannes Kepler University Linz, Altenberger Strasse 69, A-4040 Linz, Austria.
| | - Heinrich Krobath
- Institute for Theoretical Physics, Johannes Kepler University Linz, Altenberger Strasse 69, A-4040 Linz, Austria.
| | - Thomas Renger
- Institute for Theoretical Physics, Johannes Kepler University Linz, Altenberger Strasse 69, A-4040 Linz, Austria.
| | - Frank Müh
- Institute for Theoretical Physics, Johannes Kepler University Linz, Altenberger Strasse 69, A-4040 Linz, Austria.
| |
Collapse
|
8
|
Alfaro JA, Bohländer P, Dai M, Filius M, Howard CJ, van Kooten XF, Ohayon S, Pomorski A, Schmid S, Aksimentiev A, Anslyn EV, Bedran G, Cao C, Chinappi M, Coyaud E, Dekker C, Dittmar G, Drachman N, Eelkema R, Goodlett D, Hentz S, Kalathiya U, Kelleher NL, Kelly RT, Kelman Z, Kim SH, Kuster B, Rodriguez-Larrea D, Lindsay S, Maglia G, Marcotte EM, Marino JP, Masselon C, Mayer M, Samaras P, Sarthak K, Sepiashvili L, Stein D, Wanunu M, Wilhelm M, Yin P, Meller A, Joo C. The emerging landscape of single-molecule protein sequencing technologies. Nat Methods 2021; 18:604-617. [PMID: 34099939 PMCID: PMC8223677 DOI: 10.1038/s41592-021-01143-1] [Citation(s) in RCA: 150] [Impact Index Per Article: 50.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 04/02/2021] [Indexed: 02/04/2023]
Abstract
Single-cell profiling methods have had a profound impact on the understanding of cellular heterogeneity. While genomes and transcriptomes can be explored at the single-cell level, single-cell profiling of proteomes is not yet established. Here we describe new single-molecule protein sequencing and identification technologies alongside innovations in mass spectrometry that will eventually enable broad sequence coverage in single-cell profiling. These technologies will in turn facilitate biological discovery and open new avenues for ultrasensitive disease diagnostics.
Collapse
Affiliation(s)
- Javier Antonio Alfaro
- International Centre for Cancer Vaccine Science, University of Gdańsk, Gdańsk, Poland.
| | - Peggy Bohländer
- Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - Mingjie Dai
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA
| | - Mike Filius
- Department of BioNanoScience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, the Netherlands
| | - Cecil J Howard
- Department of Chemistry, University of Texas at Austin, Austin, TX, USA
| | - Xander F van Kooten
- Department of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Shilo Ohayon
- Department of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - Adam Pomorski
- Department of BioNanoScience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, the Netherlands
| | - Sonja Schmid
- NanoDynamicsLab, Laboratory of Biophysics, Wageningen University, Wageningen, the Netherlands
| | - Aleksei Aksimentiev
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Eric V Anslyn
- Department of Chemistry, University of Texas at Austin, Austin, TX, USA
| | - Georges Bedran
- International Centre for Cancer Vaccine Science, University of Gdańsk, Gdańsk, Poland
| | - Chan Cao
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Mauro Chinappi
- Dipartimento di Ingegneria Industriale, Università di Roma Tor Vergata, Rome, Italy
| | - Etienne Coyaud
- Univ. Lille, Inserm, CHU Lille, U1192-Protéomique Réponse Inflammatoire Spectrométrie de Masse-PRISM, Lille, France
| | - Cees Dekker
- Department of BioNanoScience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, the Netherlands
| | - Gunnar Dittmar
- Department of Infection and Immunity, Luxembourg Institute of Health, Strassen, Luxembourg
- Department of Life Sciences and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | | | - Rienk Eelkema
- Faculty of Applied Sciences, Delft University of Technology, Delft, the Netherlands
| | - David Goodlett
- International Centre for Cancer Vaccine Science, University of Gdańsk, Gdańsk, Poland
- Genome BC Proteomics Centre, University of Victoria, Victoria, British Columbia, Canada
| | | | - Umesh Kalathiya
- International Centre for Cancer Vaccine Science, University of Gdańsk, Gdańsk, Poland
| | - Neil L Kelleher
- Departments of Chemistry and Molecular Biosciences, and the Feinberg School of Medicine, Northwestern University, Evanston, IL, USA
| | - Ryan T Kelly
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA
| | - Zvi Kelman
- Institute for Bioscience and Biotechnology Research, National Institute of Standards and Technology, University of Maryland, Rockville, MD, USA
- Biomolecular Labeling Laboratory, Institute for Bioscience and Biotechnology Research, Rockville, MD, USA
| | - Sung Hyun Kim
- Department of BioNanoScience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, the Netherlands
| | - Bernhard Kuster
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, Germany
- Bavarian Center for Biomolecular Mass Spectrometry, Freising, Germany
| | - David Rodriguez-Larrea
- Department of Biochemistry and Molecular Biology, Biofisika Institute (CSIC, UPV/EHU), Leioa, Spain
| | - Stuart Lindsay
- Biodesign Institute, School of Molecular Sciences, Department of Physics, Arizona State University, Tempe, AZ, USA
| | - Giovanni Maglia
- Groningen Biomolecular Sciences and Biotechnology Institute, University of Groningen, Groningen, the Netherlands
| | - Edward M Marcotte
- Department of Molecular Biosciences, Center for Systems and Synthetic Biology, University of Texas at Austin, Austin, TX, USA
| | - John P Marino
- Institute for Bioscience and Biotechnology Research, National Institute of Standards and Technology, University of Maryland, Rockville, MD, USA
| | | | - Michael Mayer
- Adolphe Merkle Institute, University of Fribourg, Fribourg, Switzerland
| | - Patroklos Samaras
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, Germany
| | - Kumar Sarthak
- Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Lusia Sepiashvili
- University of Toronto, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Derek Stein
- Department of Physics, Brown University, Providence, RI, USA
| | - Meni Wanunu
- Department of Physics, Northeastern University, Boston, MA, USA
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, MA, USA
| | - Mathias Wilhelm
- Chair of Proteomics and Bioanalytics, Technische Universität München, Freising, Germany
| | - Peng Yin
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA
| | - Amit Meller
- Department of Biomedical Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
- Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa, Israel.
| | - Chirlmin Joo
- Department of BioNanoScience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, the Netherlands.
| |
Collapse
|
9
|
Nanopores: a versatile tool to study protein dynamics. Essays Biochem 2021; 65:93-107. [PMID: 33296461 DOI: 10.1042/ebc20200020] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Revised: 11/10/2020] [Accepted: 11/11/2020] [Indexed: 12/15/2022]
Abstract
Proteins are the active workhorses in our body. These biomolecules perform all vital cellular functions from DNA replication and general biosynthesis to metabolic signaling and environmental sensing. While static 3D structures are now readily available, observing the functional cycle of proteins - involving conformational changes and interactions - remains very challenging, e.g., due to ensemble averaging. However, time-resolved information is crucial to gain a mechanistic understanding of protein function. Single-molecule techniques such as FRET and force spectroscopies provide answers but can be limited by the required labelling, a narrow time bandwidth, and more. Here, we describe electrical nanopore detection as a tool for probing protein dynamics. With a time bandwidth ranging from microseconds to hours, nanopore experiments cover an exceptionally wide range of timescales that is very relevant for protein function. First, we discuss the working principle of label-free nanopore experiments, various pore designs, instrumentation, and the characteristics of nanopore signals. In the second part, we review a few nanopore experiments that solved research questions in protein science, and we compare nanopores to other single-molecule techniques. We hope to make electrical nanopore sensing more accessible to the biochemical community, and to inspire new creative solutions to resolve a variety of protein dynamics - one molecule at a time.
Collapse
|
10
|
Oswald J, Njenga R, Natriashvili A, Sarmah P, Koch HG. The Dynamic SecYEG Translocon. Front Mol Biosci 2021; 8:664241. [PMID: 33937339 PMCID: PMC8082313 DOI: 10.3389/fmolb.2021.664241] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/24/2021] [Indexed: 12/13/2022] Open
Abstract
The spatial and temporal coordination of protein transport is an essential cornerstone of the bacterial adaptation to different environmental conditions. By adjusting the protein composition of extra-cytosolic compartments, like the inner and outer membranes or the periplasmic space, protein transport mechanisms help shaping protein homeostasis in response to various metabolic cues. The universally conserved SecYEG translocon acts at the center of bacterial protein transport and mediates the translocation of newly synthesized proteins into and across the cytoplasmic membrane. The ability of the SecYEG translocon to transport an enormous variety of different substrates is in part determined by its ability to interact with multiple targeting factors, chaperones and accessory proteins. These interactions are crucial for the assisted passage of newly synthesized proteins from the cytosol into the different bacterial compartments. In this review, we summarize the current knowledge about SecYEG-mediated protein transport, primarily in the model organism Escherichia coli, and describe the dynamic interaction of the SecYEG translocon with its multiple partner proteins. We furthermore highlight how protein transport is regulated and explore recent developments in using the SecYEG translocon as an antimicrobial target.
Collapse
Affiliation(s)
- Julia Oswald
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Robert Njenga
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany.,Faculty of Biology, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Ana Natriashvili
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany.,Faculty of Biology, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Pinku Sarmah
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany.,Faculty of Biology, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| | - Hans-Georg Koch
- Institute for Biochemistry and Molecular Biology, Zentrum für Biochemie und Molekulare Medizin (ZMBZ), Faculty of Medicine, Albert Ludwigs Universität Freiburg, Freiburg, Germany
| |
Collapse
|
11
|
Characterization of the Features of Water Inside the SecY Translocon. J Membr Biol 2021; 254:133-139. [PMID: 33811496 DOI: 10.1007/s00232-021-00178-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Accepted: 03/23/2021] [Indexed: 10/21/2022]
Abstract
Despite extended experimental and computational studies, the mechanism regulating membrane protein folding and stability in cell membranes is not fully understood. In this review, I will provide a personal and partial account of the scientific efforts undertaken by Dr. Stephen White to shed light on this topic. After briefly describing the role of water and the hydrophobic effect on cellular processes, I will discuss the physical chemistry of water confined inside the SecY translocon pore. I conclude with a review of recent literature that attempts to answer fundamental questions on the pathway and energetics of translocon-guided membrane protein insertion.
Collapse
|
12
|
SecY-mediated quality control prevents the translocation of non-gated porins. Sci Rep 2020; 10:16347. [PMID: 33004891 PMCID: PMC7530735 DOI: 10.1038/s41598-020-73185-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Accepted: 09/09/2020] [Indexed: 01/24/2023] Open
Abstract
OmpC and OmpF are among the most abundant outer membrane proteins in E. coli and serve as hydrophilic channels to mediate uptake of small molecules including antibiotics. Influx selectivity is controlled by the so-called constriction zone or eyelet of the channel. Mutations in the loop domain forming the eyelet can disrupt transport selectivity and thereby interfere with bacterial viability. In this study we show that a highly conserved motif of five negatively charged amino acids in the eyelet, which is critical to regulate pore selectivity, is also required for SecY-mediated transport of OmpC and OmpF into the periplasm. Variants with a deleted or mutated motif were expressed in the cytosol and translocation was initiated. However, after signal peptide cleavage, import into the periplasm was aborted and the mutated proteins were redirected to the cytosol. Strikingly, reducing the proof-reading capacity of SecY by introducing the PrlA4 substitutions restored transport of OmpC with a mutated channel domain into the periplasm. Our study identified a SecY-mediated quality control pathway to restrict transport of outer membrane porin proteins with a deregulated channel activity into the periplasm.
Collapse
|
13
|
Winkler K, Karner A, Horner A, Hannesschlaeger C, Knyazev D, Siligan C, Zimmermann M, Kuttner R, Pohl P, Preiner J. Interaction of the motor protein SecA and the bacterial protein translocation channel SecYEG in the absence of ATP. NANOSCALE ADVANCES 2020; 2:3431-3443. [PMID: 36134293 PMCID: PMC9418451 DOI: 10.1039/d0na00427h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 06/27/2020] [Indexed: 06/16/2023]
Abstract
Translocation of many secretory proteins through the bacterial plasma membrane is facilitated by a complex of the SecYEG channel with the motor protein SecA. The ATP-free complex is unstable in detergent, raising the question how SecA may perform several rounds of ATP hydrolysis without being released from the membrane embedded SecYEG. Here we show that dual recognition of (i) SecYEG and (ii) vicinal acidic lipids confers an apparent nanomolar affinity. High-speed atomic force microscopy visualizes the complexes between monomeric SecA and SecYEG as being stable for tens of seconds. These long-lasting events and complementary shorter ones both give rise to single ion channel openings of equal duration. Furthermore, luminescence resonance energy transfer reveals two conformations of the SecYEG-SecA complex that differ in the protrusion depth of SecA's two-helix finger into SecYEG's aqueous channel. Such movement of the finger is in line with the power stroke mechanism of protein translocation.
Collapse
Affiliation(s)
- Klemens Winkler
- Johannes Kepler University Linz, Institute of Biophysics 4020 Linz Austria
| | - Andreas Karner
- University of Applied Sciences Upper Austria, TIMED Center 4020 Linz Austria
| | - Andreas Horner
- Johannes Kepler University Linz, Institute of Biophysics 4020 Linz Austria
| | | | - Denis Knyazev
- Johannes Kepler University Linz, Institute of Biophysics 4020 Linz Austria
| | - Christine Siligan
- Johannes Kepler University Linz, Institute of Biophysics 4020 Linz Austria
| | - Mirjam Zimmermann
- Johannes Kepler University Linz, Institute of Biophysics 4020 Linz Austria
| | - Roland Kuttner
- Johannes Kepler University Linz, Institute of Biophysics 4020 Linz Austria
| | - Peter Pohl
- Johannes Kepler University Linz, Institute of Biophysics 4020 Linz Austria
| | - Johannes Preiner
- University of Applied Sciences Upper Austria, TIMED Center 4020 Linz Austria
| |
Collapse
|
14
|
Cavalier-Smith T, Chao EEY. Multidomain ribosomal protein trees and the planctobacterial origin of neomura (eukaryotes, archaebacteria). PROTOPLASMA 2020. [PMID: 31900730 DOI: 10.1007/s00709-019-01442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Palaeontologically, eubacteria are > 3× older than neomura (eukaryotes, archaebacteria). Cell biology contrasts ancestral eubacterial murein peptidoglycan walls and derived neomuran N-linked glycoprotein coats/walls. Misinterpreting long stems connecting clade neomura to eubacteria on ribosomal sequence trees (plus misinterpreted protein paralogue trees) obscured this historical pattern. Universal multiprotein ribosomal protein (RP) trees, more accurate than rRNA trees, are taxonomically undersampled. To reduce contradictions with genically richer eukaryote trees and improve eubacterial phylogeny, we constructed site-heterogeneous and maximum-likelihood universal three-domain, two-domain, and single-domain trees for 143 eukaryotes (branching now congruent with 187-protein trees), 60 archaebacteria, and 151 taxonomically representative eubacteria, using 51 and 26 RPs. Site-heterogeneous trees greatly improve eubacterial phylogeny and higher classification, e.g. showing gracilicute monophyly, that many 'rDNA-phyla' belong in Proteobacteria, and reveal robust new phyla Synthermota and Aquithermota. Monoderm Posibacteria and Mollicutes (two separate wall losses) are both polyphyletic: multiple outer membrane losses in Endobacteria occurred separately from Actinobacteria; neither phylum is related to Chloroflexi, the most divergent prokaryotes, which originated photosynthesis (new model proposed). RP trees support an eozoan root for eukaryotes and are consistent with archaebacteria being their sisters and rooted between Filarchaeota (=Proteoarchaeota, including 'Asgardia') and Euryarchaeota sensu-lato (including ultrasimplified 'DPANN' whose long branches often distort trees). Two-domain trees group eukaryotes within Planctobacteria, and archaebacteria with Planctobacteria/Sphingobacteria. Integrated molecular/palaeontological evidence favours negibacterial ancestors for neomura and all life. Unique presence of key pre-neomuran characters favours Planctobacteria only as ancestral to neomura, which apparently arose by coevolutionary repercussions (explained here in detail, including RP replacement) of simultaneous outer membrane and murein loss. Planctobacterial C-1 methanotrophic enzymes are likely ancestral to archaebacterial methanogenesis and β-propeller-α-solenoid proteins to eukaryotic vesicle coats, nuclear-pore-complexes, and intraciliary transport. Planctobacterial chaperone-independent 4/5-protofilament microtubules and MamK actin-ancestors prepared for eukaryote intracellular motility, mitosis, cytokinesis, and phagocytosis. We refute numerous wrong ideas about the universal tree.
Collapse
Affiliation(s)
| | - Ema E-Yung Chao
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| |
Collapse
|
15
|
Cavalier-Smith T, Chao EEY. Multidomain ribosomal protein trees and the planctobacterial origin of neomura (eukaryotes, archaebacteria). PROTOPLASMA 2020; 257:621-753. [PMID: 31900730 PMCID: PMC7203096 DOI: 10.1007/s00709-019-01442-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 09/19/2019] [Indexed: 05/02/2023]
Abstract
Palaeontologically, eubacteria are > 3× older than neomura (eukaryotes, archaebacteria). Cell biology contrasts ancestral eubacterial murein peptidoglycan walls and derived neomuran N-linked glycoprotein coats/walls. Misinterpreting long stems connecting clade neomura to eubacteria on ribosomal sequence trees (plus misinterpreted protein paralogue trees) obscured this historical pattern. Universal multiprotein ribosomal protein (RP) trees, more accurate than rRNA trees, are taxonomically undersampled. To reduce contradictions with genically richer eukaryote trees and improve eubacterial phylogeny, we constructed site-heterogeneous and maximum-likelihood universal three-domain, two-domain, and single-domain trees for 143 eukaryotes (branching now congruent with 187-protein trees), 60 archaebacteria, and 151 taxonomically representative eubacteria, using 51 and 26 RPs. Site-heterogeneous trees greatly improve eubacterial phylogeny and higher classification, e.g. showing gracilicute monophyly, that many 'rDNA-phyla' belong in Proteobacteria, and reveal robust new phyla Synthermota and Aquithermota. Monoderm Posibacteria and Mollicutes (two separate wall losses) are both polyphyletic: multiple outer membrane losses in Endobacteria occurred separately from Actinobacteria; neither phylum is related to Chloroflexi, the most divergent prokaryotes, which originated photosynthesis (new model proposed). RP trees support an eozoan root for eukaryotes and are consistent with archaebacteria being their sisters and rooted between Filarchaeota (=Proteoarchaeota, including 'Asgardia') and Euryarchaeota sensu-lato (including ultrasimplified 'DPANN' whose long branches often distort trees). Two-domain trees group eukaryotes within Planctobacteria, and archaebacteria with Planctobacteria/Sphingobacteria. Integrated molecular/palaeontological evidence favours negibacterial ancestors for neomura and all life. Unique presence of key pre-neomuran characters favours Planctobacteria only as ancestral to neomura, which apparently arose by coevolutionary repercussions (explained here in detail, including RP replacement) of simultaneous outer membrane and murein loss. Planctobacterial C-1 methanotrophic enzymes are likely ancestral to archaebacterial methanogenesis and β-propeller-α-solenoid proteins to eukaryotic vesicle coats, nuclear-pore-complexes, and intraciliary transport. Planctobacterial chaperone-independent 4/5-protofilament microtubules and MamK actin-ancestors prepared for eukaryote intracellular motility, mitosis, cytokinesis, and phagocytosis. We refute numerous wrong ideas about the universal tree.
Collapse
Affiliation(s)
| | - Ema E-Yung Chao
- Department of Zoology, University of Oxford, South Parks Road, Oxford, OX1 3PS, UK
| |
Collapse
|
16
|
Mercier E, Wintermeyer W, Rodnina MV. Co-translational insertion and topogenesis of bacterial membrane proteins monitored in real time. EMBO J 2020; 39:e104054. [PMID: 32311161 PMCID: PMC7396858 DOI: 10.15252/embj.2019104054] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 02/27/2020] [Accepted: 03/03/2020] [Indexed: 01/23/2023] Open
Abstract
Integral membrane proteins insert into the bacterial inner membrane co‐translationally via the translocon. Transmembrane (TM) segments of nascent proteins adopt their native topological arrangement with the N‐terminus of the first TM (TM1) oriented to the outside (type I) or the inside (type II) of the cell. Here, we study TM1 topogenesis during ongoing translation in a bacterial in vitro system, applying real‐time FRET and protease protection assays. We find that TM1 of the type I protein LepB reaches the translocon immediately upon emerging from the ribosome. In contrast, the type II protein EmrD requires a longer nascent chain before TM1 reaches the translocon and adopts its topology by looping inside the ribosomal peptide exit tunnel. Looping presumably is mediated by interactions between positive charges at the N‐terminus of TM1 and negative charges in the tunnel wall. Early TM1 inversion is abrogated by charge reversal at the N‐terminus. Kinetic analysis also shows that co‐translational membrane insertion of TM1 is intrinsically rapid and rate‐limited by translation. Thus, the ribosome has an important role in membrane protein topogenesis.
Collapse
Affiliation(s)
- Evan Mercier
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Wolfgang Wintermeyer
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Marina V Rodnina
- Department of Physical Biochemistry, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| |
Collapse
|
17
|
Cardiolipin is required in vivo for the stability of bacterial translocon and optimal membrane protein translocation and insertion. Sci Rep 2020; 10:6296. [PMID: 32286407 PMCID: PMC7156725 DOI: 10.1038/s41598-020-63280-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 03/25/2020] [Indexed: 01/05/2023] Open
Abstract
Translocation of preproteins across the Escherichia coli inner membrane requires anionic lipids by virtue of their negative head-group charge either in vivo or in situ. However, available results do not differentiate between the roles of monoanionic phosphatidylglycerol and dianionic cardiolipin (CL) in this essential membrane-related process. To define in vivo the molecular steps affected by the absence of CL in protein translocation and insertion, we analyzed translocon activity, SecYEG stability and its interaction with SecA in an E. coli mutant devoid of CL. Although no growth defects were observed, co- and post-translational translocation of α-helical proteins across inner membrane and the assembly of outer membrane β-barrel precursors were severely compromised in CL-lacking cells. Components of proton-motive force which could impair protein insertion into and translocation across the inner membrane, were unaffected. However, stability of the dimeric SecYEG complex and oligomerization properties of SecA were strongly compromised while the levels of individual SecYEG translocon components, SecA and insertase YidC were largely unaffected. These results demonstrate that CL is required in vivo for the stability of the bacterial translocon and its efficient function in co-translational insertion into and translocation across the inner membrane of E. coli.
Collapse
|
18
|
Jauss B, Petriman NA, Drepper F, Franz L, Sachelaru I, Welte T, Steinberg R, Warscheid B, Koch HG. Noncompetitive binding of PpiD and YidC to the SecYEG translocon expands the global view on the SecYEG interactome in Escherichia coli. J Biol Chem 2019; 294:19167-19183. [PMID: 31699901 DOI: 10.1074/jbc.ra119.010686] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 10/25/2019] [Indexed: 12/22/2022] Open
Abstract
The SecYEG translocon constitutes the major protein transport channel in bacteria and transfers an enormous variety of different secretory and inner-membrane proteins. The minimal core of the SecYEG translocon consists of three inner-membrane proteins, SecY, SecE, and SecG, which, together with appropriate targeting factors, are sufficient for protein transport in vitro However, in vivo the SecYEG translocon has been shown to associate with multiple partner proteins, likely allowing the SecYEG translocon to process its diverse substrates. To obtain a global view on SecYEG plasticity in Escherichia coli, here we performed a quantitative interaction proteomic analysis, which identified several known SecYEG-interacting proteins, verified the interaction of SecYEG with quality-control proteins, and revealed several previously unknown putative SecYEG-interacting proteins. Surprisingly, we found that the chaperone complex PpiD/YfgM is the most prominent interaction partner of SecYEG. Detailed analyses of the PpiD-SecY interaction by site-directed cross-linking revealed that PpiD and the established SecY partner protein YidC use almost completely-overlapping binding sites on SecY. Both PpiD and YidC contacted the lateral gate, the plug domain, and the periplasmic cavity of SecY. However, quantitative MS and cross-linking analyses revealed that despite having almost identical binding sites, their binding to SecY is noncompetitive. This observation suggests that the SecYEG translocon forms different substrate-independent subassemblies in which SecYEG either associates with YidC or with the PpiD/YfgM complex. In summary, the results of this study indicate that the PpiD/YfgM chaperone complex is a primary interaction partner of the SecYEG translocon.
Collapse
Affiliation(s)
- Benjamin Jauss
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Narcis-Adrian Petriman
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany.,Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Friedel Drepper
- Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany.,Institute of Biology II, Biochemistry and Functional Proteomics, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Lisa Franz
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Ilie Sachelaru
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Thomas Welte
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Ruth Steinberg
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Bettina Warscheid
- Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany.,Institute of Biology II, Biochemistry and Functional Proteomics, Faculty of Biology, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany.,Signalling Research Centres BIOSS and CIBSS, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| | - Hans-Georg Koch
- Institute of Biochemistry and Molecular Biology, ZBMZ, Faculty of Medicine, Albert-Ludwigs-University Freiburg, 79104 Freiburg, Germany
| |
Collapse
|
19
|
Steinberg R, Knüpffer L, Origi A, Asti R, Koch HG. Co-translational protein targeting in bacteria. FEMS Microbiol Lett 2019; 365:4966980. [PMID: 29790984 DOI: 10.1093/femsle/fny095] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 04/09/2018] [Indexed: 01/16/2023] Open
Abstract
About 30% of all bacterial proteins execute their function outside of the cytosol and have to be transported into or across the cytoplasmic membrane. Bacteria use multiple protein transport systems in parallel, but the majority of proteins engage two distinct targeting systems. One is the co-translational targeting by two universally conserved GTPases, the signal recognition particle (SRP) and its receptor FtsY, which deliver inner membrane proteins to either the SecYEG translocon or the YidC insertase for membrane insertion. The other targeting system depends on the ATPase SecA, which targets secretory proteins, i.e. periplasmic and outer membrane proteins, to SecYEG for their subsequent ATP-dependent translocation. While SRP selects its substrates already very early during their synthesis, the recognition of secretory proteins by SecA is believed to occur primarily after translation termination, i.e. post-translationally. In this review we highlight recent progress on how SRP recognizes its substrates at the ribosome and how the fidelity of the targeting reaction to SecYEG is maintained. We furthermore discuss similarities and differences in the SRP-dependent targeting to either SecYEG or YidC and summarize recent results that suggest that some membrane proteins are co-translationally targeted by SecA.
Collapse
Affiliation(s)
- Ruth Steinberg
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| | - Lara Knüpffer
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| | - Andrea Origi
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany.,Faculty of Biology, Albert-Ludwigs-University Freiburg, Schänzlestr. 1, Freiburg D-79104, Germany
| | - Rossella Asti
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| | - Hans-Georg Koch
- Institute of Biochemistry and Molecular Biology, Faculty of Medicine, Albert-Ludwigs University Freiburg, Stefan Meier Str. 17, Freiburg D-79104, Germany
| |
Collapse
|
20
|
Corradi V, Sejdiu BI, Mesa-Galloso H, Abdizadeh H, Noskov SY, Marrink SJ, Tieleman DP. Emerging Diversity in Lipid-Protein Interactions. Chem Rev 2019; 119:5775-5848. [PMID: 30758191 PMCID: PMC6509647 DOI: 10.1021/acs.chemrev.8b00451] [Citation(s) in RCA: 245] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
![]()
Membrane
lipids interact with proteins in a variety of ways, ranging
from providing a stable membrane environment for proteins to being
embedded in to detailed roles in complicated and well-regulated protein
functions. Experimental and computational advances are converging
in a rapidly expanding research area of lipid–protein interactions.
Experimentally, the database of high-resolution membrane protein structures
is growing, as are capabilities to identify the complex lipid composition
of different membranes, to probe the challenging time and length scales
of lipid–protein interactions, and to link lipid–protein
interactions to protein function in a variety of proteins. Computationally,
more accurate membrane models and more powerful computers now enable
a detailed look at lipid–protein interactions and increasing
overlap with experimental observations for validation and joint interpretation
of simulation and experiment. Here we review papers that use computational
approaches to study detailed lipid–protein interactions, together
with brief experimental and physiological contexts, aiming at comprehensive
coverage of simulation papers in the last five years. Overall, a complex
picture of lipid–protein interactions emerges, through a range
of mechanisms including modulation of the physical properties of the
lipid environment, detailed chemical interactions between lipids and
proteins, and key functional roles of very specific lipids binding
to well-defined binding sites on proteins. Computationally, despite
important limitations, molecular dynamics simulations with current
computer power and theoretical models are now in an excellent position
to answer detailed questions about lipid–protein interactions.
Collapse
Affiliation(s)
- Valentina Corradi
- Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive NW , Calgary , Alberta T2N 1N4 , Canada
| | - Besian I Sejdiu
- Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive NW , Calgary , Alberta T2N 1N4 , Canada
| | - Haydee Mesa-Galloso
- Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive NW , Calgary , Alberta T2N 1N4 , Canada
| | - Haleh Abdizadeh
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials , University of Groningen , Nijenborgh 7 , 9747 AG Groningen , The Netherlands
| | - Sergei Yu Noskov
- Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive NW , Calgary , Alberta T2N 1N4 , Canada
| | - Siewert J Marrink
- Groningen Biomolecular Sciences and Biotechnology Institute and Zernike Institute for Advanced Materials , University of Groningen , Nijenborgh 7 , 9747 AG Groningen , The Netherlands
| | - D Peter Tieleman
- Centre for Molecular Simulation and Department of Biological Sciences , University of Calgary , 2500 University Drive NW , Calgary , Alberta T2N 1N4 , Canada
| |
Collapse
|
21
|
Uhl M, Seifert U. Force-dependent diffusion coefficient of molecular Brownian ratchets. Phys Rev E 2018; 98:022402. [PMID: 30253613 DOI: 10.1103/physreve.98.022402] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Indexed: 11/07/2022]
Abstract
We study the mean velocity and diffusion constant in three related models of molecular Brownian ratchets. Brownian ratchets can be used to describe translocation of biopolymers like DNA through nanopores in cells in the presence of chaperones on the trans side of the pore. Chaperones can bind to the polymer and prevent it from sliding back through the pore. First, we study a simple model that describes the translocation in terms of an asymmetric random walk. It serves as an introductory example but already captures the main features of a Brownian ratchet. We then provide an analytical expression for the diffusion constant in the classical model of a translocation ratchet that was first proposed by Peskin et al. [C. S. Peskin, G. M. Odell, and G. F. Oster, Cellular motions and thermal fluctuations: The Brownian ratchet, Biophys. J. 65, 316 (1993)BIOJAU0006-349510.1016/S0006-3495(93)81035-X]. This model is based on the assumption that the binding and unbinding of the chaperones are much faster than the diffusion of the DNA strand. To remedy this shortcoming, we propose a modified model that is also applicable if the (un)binding rates are finite. We calculate the force-dependent mean velocity and diffusivity for this model and compare the results to the original one. Our analysis shows that for large pulling forces the predictions of both models can differ strongly even if the (un)binding rates are large in comparison to the diffusion timescale but still finite. Furthermore, implications of the thermodynamic uncertainty relation on the efficiency of Brownian ratchets are discussed.
Collapse
Affiliation(s)
- Matthias Uhl
- II. Institut für Theoretische Physik, Universität Stuttgart, 70550 Stuttgart, Germany
| | - Udo Seifert
- II. Institut für Theoretische Physik, Universität Stuttgart, 70550 Stuttgart, Germany
| |
Collapse
|
22
|
Bondar AN, Keller S. Lipid Membranes and Reactions at Lipid Interfaces: Theory, Experiments, and Applications. J Membr Biol 2018; 251:295-298. [DOI: 10.1007/s00232-018-0039-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Accepted: 06/25/2018] [Indexed: 12/11/2022]
|