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Karimullina E, Guo Y, Khan HM, Emde T, Quade B, Leo RD, Otwinowski Z, Tieleman Peter D, Borek D, Savchenko A. Structural architecture of TolQ-TolR inner membrane protein complex from opportunistic pathogen Acinetobacter baumannii. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.19.599759. [PMID: 38948712 PMCID: PMC11212960 DOI: 10.1101/2024.06.19.599759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Gram-negative bacteria harness the proton motive force (PMF) within their inner membrane (IM) to uphold the integrity of their cell envelope, an indispensable aspect for both division and survival. The IM TolQ-TolR complex is the essential part of the Tol-Pal system, serving as a conduit for PMF energy transfer to the outer membrane. Here we present cryo-EM reconstructions of Acinetobacter baumannii TolQ in apo and TolR- bound forms at atomic resolution. The apo TolQ configuration manifests as a symmetric pentameric pore, featuring a trans-membrane funnel leading towards a cytoplasmic chamber. In contrast, the TolQ-TolR complex assumes a proton non-permeable stance, characterized by the TolQ pentamer's flexure to accommodate the TolR dimer, where two protomers undergo a translation-based relationship. Our structure-guided analysis and simulations support the rotor-stator mechanism of action, wherein the rotation of the TolQ pentamer harmonizes with the TolR protomers' interplay. These findings broaden our mechanistic comprehension of molecular stator units empowering critical functions within the Gram-negative bacterial cell envelope. Teaser Apo TolQ and TolQ-TolR structures depict structural rearrangements required for cell envelope organization in bacterial cell division.
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2
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Baquero F, Beis K, Craik DJ, Li Y, Link AJ, Rebuffat S, Salomón R, Severinov K, Zirah S, Hegemann JD. The pearl jubilee of microcin J25: thirty years of research on an exceptional lasso peptide. Nat Prod Rep 2024; 41:469-511. [PMID: 38164764 DOI: 10.1039/d3np00046j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Covering: 1992 up to 2023Since their discovery, lasso peptides went from peculiarities to be recognized as a major family of ribosomally synthesized and post-translationally modified peptide (RiPP) natural products that were shown to be spread throughout the bacterial kingdom. Microcin J25 was first described in 1992, making it one of the earliest known lasso peptides. No other lasso peptide has since then been studied to such an extent as microcin J25, yet, previous review articles merely skimmed over all the research done on this exceptional lasso peptide. Therefore, to commemorate the 30th anniversary of its first report, we give a comprehensive overview of all literature related to microcin J25. This review article spans the early work towards the discovery of microcin J25, its biosynthetic gene cluster, and the elucidation of its three-dimensional, threaded lasso structure. Furthermore, the current knowledge about the biosynthesis of microcin J25 and lasso peptides in general is summarized and a detailed overview is given on the biological activities associated with microcin J25, including means of self-immunity, uptake into target bacteria, inhibition of the Gram-negative RNA polymerase, and the effects of microcin J25 on mitochondria. The in vitro and in vivo models used to study the potential utility of microcin J25 in a (veterinary) medicine context are discussed and the efforts that went into employing the microcin J25 scaffold in bioengineering contexts are summed up.
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Affiliation(s)
- Fernando Baquero
- Department of Microbiology, Ramón y Cajal University Hospital and Ramón y Cajal Institute for Health Research (IRYCIS), Madrid, Spain
- Network Center for Research in Epidemiology and Public Health (CIBER-ESP), Madrid, Spain
| | - Konstantinos Beis
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
- Rutherford Appleton Laboratory, Research Complex at Harwell, Didcot, Oxfordshire OX11 0FA, UK
| | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, 4072 Brisbane, Queensland, Australia
| | - Yanyan Li
- Laboratoire Molécules de Communication et Adaptation des Microorganismes (MCAM), UMR 7245, Muséum National d'Histoire Naturelle (MNHN), Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - A James Link
- Departments of Chemical and Biological Engineering, Chemistry, and Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Sylvie Rebuffat
- Laboratoire Molécules de Communication et Adaptation des Microorganismes (MCAM), UMR 7245, Muséum National d'Histoire Naturelle (MNHN), Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Raúl Salomón
- Instituto de Química Biológica "Dr Bernabé Bloj", Facultad de Bioquímica, Química y Farmacia, Instituto Superior de Investigaciones Biológicas (INSIBIO), CONICET-UNT, San Miguel de Tucumán, Argentina
| | - Konstantin Severinov
- Waksman Institute for Microbiology, Rutgers, The State University of New Jersey, Piscataway, NJ, USA
| | - Séverine Zirah
- Laboratoire Molécules de Communication et Adaptation des Microorganismes (MCAM), UMR 7245, Muséum National d'Histoire Naturelle (MNHN), Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Julian D Hegemann
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University Campus, 66123 Saarbrücken, Germany.
- Department of Pharmacy, Campus E8 1, Saarland University, 66123 Saarbrücken, Germany
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3
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Loll PJ, Grasty KC, Shultis DD, Guzman NJ, Wiener MC. Discovery and structural characterization of the D-box, a conserved TonB motif that couples an inner-membrane motor to outer-membrane transport. J Biol Chem 2024; 300:105723. [PMID: 38311172 PMCID: PMC10907165 DOI: 10.1016/j.jbc.2024.105723] [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: 01/07/2024] [Revised: 01/26/2024] [Accepted: 01/28/2024] [Indexed: 02/10/2024] Open
Abstract
Gram-negative bacteria use TonB-dependent transport to take up nutrients from the external environment, employing the Ton complex to import a variety of nutrients that are either scarce or too large to cross the outer membrane unaided. The Ton complex contains an inner-membrane motor (ExbBD) that generates force, as well as nutrient-specific transport proteins on the outer membrane. These two components are coupled by TonB, which transmits the force from the inner to the outer membrane. TonB contains an N-terminus anchored in the inner membrane, a C-terminal domain that binds the outer-membrane transporter, and a proline-rich linker connecting the two. While much is known about the interaction between TonB and outer-membrane transporters, the critical interface between TonB and ExbBD is less well understood. Here, we identify a conserved motif within TonB that we term the D-box, which serves as an attachment point for ExbD. We characterize the interaction between ExbD and the D-box both functionally and structurally, showing that a homodimer of ExbD captures one copy of the D-box peptide via beta-strand recruitment. We additionally show that both the D-box motif and ExbD are conserved in a range of Gram-negative bacteria, including members of the ESKAPE group of pathogens. The ExbD:D-box interaction is likely to represent an important aspect of force transduction between the inner and outer membranes. Given that TonB-dependent transport is an important contributor to virulence, this interaction is an intriguing potential target for novel antibacterial therapies.
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Affiliation(s)
- Patrick J Loll
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA.
| | - Kimberly C Grasty
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - David D Shultis
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA
| | - Nicholas J Guzman
- Department of Biochemistry and Molecular Biology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Michael C Wiener
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia, USA.
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4
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Zinke M, Lejeune M, Mechaly A, Bardiaux B, Boneca IG, Delepelaire P, Izadi-Pruneyre N. Ton motor conformational switch and peptidoglycan role in bacterial nutrient uptake. Nat Commun 2024; 15:331. [PMID: 38184686 PMCID: PMC10771500 DOI: 10.1038/s41467-023-44606-z] [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: 07/20/2023] [Accepted: 12/20/2023] [Indexed: 01/08/2024] Open
Abstract
Active nutrient uptake is fundamental for survival and pathogenicity of Gram-negative bacteria, which operate a multi-protein Ton system to transport essential nutrients like metals and vitamins. This system harnesses the proton motive force at the inner membrane to energize the import through the outer membrane, but the mechanism of energy transfer remains enigmatic. Here, we study the periplasmic domain of ExbD, a crucial component of the proton channel of the Ton system. We show that this domain is a dynamic dimer switching between two conformations representing the proton channel's open and closed states. By in vivo phenotypic assays we demonstrate that this conformational switch is essential for the nutrient uptake by bacteria. The open state of ExbD triggers a disorder to order transition of TonB, enabling TonB to supply energy to the nutrient transporter. We also reveal the anchoring role of the peptidoglycan layer in this mechanism. Herein, we propose a mechanistic model for the Ton system, emphasizing ExbD duality and the pivotal catalytic role of peptidoglycan. Sequence analysis suggests that this mechanism is conserved in other systems energizing gliding motility and membrane integrity. Our study fills important gaps in understanding bacterial motor mechanism and proposes novel antibacterial strategies.
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Affiliation(s)
- Maximilian Zinke
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Bacterial Transmembrane Systems Unit, F-75015, Paris, France
| | - Maylis Lejeune
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Bacterial Transmembrane Systems Unit, F-75015, Paris, France
| | - Ariel Mechaly
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Crystallography Platform, F-75015, Paris, France
| | - Benjamin Bardiaux
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Bacterial Transmembrane Systems Unit, F-75015, Paris, France
| | - Ivo Gomperts Boneca
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, INSERM U1306, Unité de Biologie et génétique de la paroi bactérienne, F-75015, Paris, France
| | - Philippe Delepelaire
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, Université Paris Cité, UMR7099 CNRS, F-75005, Paris, France
- Institut de Biologie Physico-Chimique, F-75005, Paris, France
| | - Nadia Izadi-Pruneyre
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Bacterial Transmembrane Systems Unit, F-75015, Paris, France.
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5
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Will V, Gasser V, Kuhn L, Fritsch S, Heinrichs DE, Schalk IJ. Siderophore specificities of the Pseudomonas aeruginosa TonB-dependent transporters ChtA and ActA. FEBS Lett 2023; 597:2963-2974. [PMID: 37758521 DOI: 10.1002/1873-3468.14740] [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: 07/27/2023] [Revised: 09/12/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023]
Abstract
Iron is an essential nutrient for the survival and virulence of Pseudomonas aeruginosa. The pathogen expresses at least 15 different iron-uptake pathways, the majority involving small iron chelators called siderophores. P. aeruginosa produces two siderophores, but can also use many produced by other microorganisms. This implies that the bacterium expresses appropriate TonB-dependent transporters (TBDTs) at the outer membrane to import the ferric form of each of the siderophores used. Here, we show that the two α-carboxylate-type siderophores rhizoferrin-Fe and staphyloferrin A-Fe are transported into P. aeruginosa cells by the TBDT ActA. Among the mixed α-carboxylate/hydroxamate-type siderophores, we found aerobactin-Fe to be transported by ChtA and schizokinen-Fe and arthrobactin-Fe by ChtA and another unidentified TBDT. Our findings enhance the understanding of the adaptability of P. aeruginosa and hold significant implications for developing novel strategies to combat antibiotic resistance.
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Affiliation(s)
- Virginie Will
- CNRS, University of Strasbourg, UMR7242, ESBS, Strasbourg, France
- University of Strasbourg, UMR7242, ESBS, Strasbourg, France
| | - Véronique Gasser
- CNRS, University of Strasbourg, UMR7242, ESBS, Strasbourg, France
- University of Strasbourg, UMR7242, ESBS, Strasbourg, France
| | - Lauriane Kuhn
- Plateforme Proteomique Strasbourg - Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS FR1589, Strasbourg Cedex, France
| | - Sarah Fritsch
- CNRS, University of Strasbourg, UMR7242, ESBS, Strasbourg, France
- University of Strasbourg, UMR7242, ESBS, Strasbourg, France
| | - David E Heinrichs
- Department of Microbiology and Immunology, University of Western Ontario, London, Canada
| | - Isabelle J Schalk
- CNRS, University of Strasbourg, UMR7242, ESBS, Strasbourg, France
- University of Strasbourg, UMR7242, ESBS, Strasbourg, France
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6
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Pollet RM, Foley MH, Kumar SS, Elmore A, Jabara NT, Venkatesh S, Vasconcelos Pereira G, Martens EC, Koropatkin NM. Multiple TonB homologs are important for carbohydrate utilization by Bacteroides thetaiotaomicron. J Bacteriol 2023; 205:e0021823. [PMID: 37874167 PMCID: PMC10662123 DOI: 10.1128/jb.00218-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Accepted: 09/28/2023] [Indexed: 10/25/2023] Open
Abstract
IMPORTANCE The human gut microbiota, including Bacteroides, is required for the degradation of otherwise undigestible polysaccharides. The gut microbiota uses polysaccharides as an energy source, and fermentation products such as short-chain fatty acids are beneficial to the human host. This use of polysaccharides is dependent on the proper pairing of a TonB protein with polysaccharide-specific TonB-dependent transporters; however, the formation of these protein complexes is poorly understood. In this study, we examine the role of 11 predicted TonB homologs in polysaccharide uptake. We show that two proteins, TonB4 and TonB6, may be functionally redundant. This may allow for the development of drugs targeting Bacteroides species containing only a TonB4 homolog with limited impact on species encoding the redundant TonB6.
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Affiliation(s)
- Rebecca M. Pollet
- Department of Chemistry, Vassar College, Poughkeepsie, New York, USA
- Biochemistry Program, Vassar College, Poughkeepsie, New York, USA
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Matthew H. Foley
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Supriya Suresh Kumar
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Amanda Elmore
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | | | - Sameeksha Venkatesh
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | | | - Eric C. Martens
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Nicole M. Koropatkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, USA
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7
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Zinke M, Lejeune M, Mechaly A, Bardiaux B, Boneca IG, Delepelaire P, Izadi-Pruneyre N. Ton Motor Conformational Switch and Peptidoglycan Role in Bacterial Nutrient Uptake. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.11.552980. [PMID: 37609138 PMCID: PMC10441417 DOI: 10.1101/2023.08.11.552980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Active nutrient uptake is fundamental for survival and pathogenicity of Gram-negative bacteria, which operate a multi-protein Ton system to transport essential nutrients like metals and vitamins. This system harnesses the proton motive force at the inner membrane to energize the import through the outer membrane, but the mechanism of energy transfer remains enigmatic. Here, we study the periplasmic domain of ExbD, a crucial component of the proton channel of the Ton system. We show that this domain is a dynamic dimer switching between two conformations representing the proton channel's open and closed states. By in vivo phenotypic assays we demonstrate that this conformational switch is essential for the nutrient uptake by bacteria. The open state of ExbD triggers a disorder to order transition of TonB, enabling TonB to supply energy to the nutrient transporter. We also reveal the anchoring role of the peptidoglycan layer in this mechanism. Herein, we propose a mechanistic model for the Ton system, emphasizing ExbD duality and the pivotal catalytic role of peptidoglycan. Sequence analysis suggests that this mechanism is conserved in other systems energizing gliding motility and membrane integrity. Our study fills important gaps in understanding bacterial motor mechanism and proposes novel antibacterial strategies.
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Affiliation(s)
- Maximilian Zinke
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Bacterial Transmembrane Systems Unit, F-75015 Paris, France
| | - Maylis Lejeune
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Bacterial Transmembrane Systems Unit, F-75015 Paris, France
| | - Ariel Mechaly
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Crystallography Platform, F-75015 Paris, France
| | - Benjamin Bardiaux
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Bacterial Transmembrane Systems Unit, F-75015 Paris, France
| | - Ivo Gomperts Boneca
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, INSERM U1306, Unité de Biologie et génétique de la paroi bactérienne F-75015, Paris, France
| | - Philippe Delepelaire
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, Université Paris Cité, UMR7099 CNRS, F-75005, Paris, France
- Institut de Biologie Physico-Chimique, F-75005, Paris, France
| | - Nadia Izadi-Pruneyre
- Institut Pasteur, Université Paris Cité, CNRS UMR3528, Bacterial Transmembrane Systems Unit, F-75015 Paris, France
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8
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Pellegri C, Moreau A, Duché D, Houot L. Direct interaction between fd phage pilot protein pIII and the TolQ-TolR proton-dependent motor provides new insights into the import of filamentous phages. J Biol Chem 2023; 299:105048. [PMID: 37451481 PMCID: PMC10424213 DOI: 10.1016/j.jbc.2023.105048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 07/18/2023] Open
Abstract
Filamentous phages are one of the simplest examples of viruses with a protein capsid that protects a circular single-stranded DNA genome. The infection is very specific, nonlytic, and can strongly affect the physiology or provide new pathogenic factors to its bacterial host. The infection process is proposed to rely on a pore-forming mechanism similar to that of certain nonenveloped eukaryotic viruses. The Ff coliphages (including M13, fd, and f1) have been intensively studied and were used to establish the sequence of events taking place for efficient crossing of the host envelope structure. However, the mechanism involved in the penetration of the cell inner membrane is not well understood. Here, we identify new host players involved in the phage translocation mechanism. Interaction studies by a combination of in vivo biochemical methods demonstrate that the adhesion protein pIII located at the tip of the phage binds to TolQ and TolR, two proteins that form a conserved proton-dependent molecular motor in the inner membrane of the host cell. Moreover, in vivo cysteine cross-linking studies reveal that the interactions between the pIII and TolQ or TolR occur between their transmembrane helix domains and may be responding to the proton motive force status of the cell. These results allow us to propose a model for the late stage of filamentous phage translocation mediated by multiple interactions with each individual component of the host TolQRA complex.
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Affiliation(s)
- Callypso Pellegri
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ - CNRS, Marseille Cedex, France
| | - Ambre Moreau
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ - CNRS, Marseille Cedex, France
| | - Denis Duché
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ - CNRS, Marseille Cedex, France
| | - Laetitia Houot
- Laboratoire d'Ingénierie des Systèmes Macromoléculaires, UMR7255, Institut de Microbiologie de la Méditerranée, Aix-Marseille Univ - CNRS, Marseille Cedex, France.
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9
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Chen M, Shu Y, Li Q, Kang Z, Liu T, Zhou H, Huang W, Zhang W. Bacteroides ovatus accelerates metformin-induced vitamin B12 deficiency in type 2 diabetes patients by accumulating cobalamin. NPJ Biofilms Microbiomes 2023; 9:51. [PMID: 37488134 PMCID: PMC10366088 DOI: 10.1038/s41522-023-00419-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Accepted: 07/10/2023] [Indexed: 07/26/2023] Open
Abstract
Vitamin B12 (VB12) deficiency, which may lead to hematologic and neurologic symptoms, has been associated with metformin use, but the underlying mechanism is unclear. Here we report the B. ovatus as an effective VB12 catcher which was enriched in the type 2 diabetes patients suffered from VB12 deficiency after 3 to 6 months of metformin treatment. Colonization of B. ovatus increased the plasma levels of methylmalonic acid and homocysteine in high-fat diet (HFD)-fed mice treated with metformin, and compromised the efficacy of metformin against the HFD-induced metabolic disorders. Mechanistically, metformin increased the intracellular accumulation of VB12 in B. ovatus via btuB upregulation and promoted ATP production for energy-dependent translocation of VB12 transporters at the inner membrane, leading to an enhanced colonization of B. ovatus to compete for VB12 with hosts and subsequently an aggravated VB12 deficiency in the host. Our findings illustrate a previously unappreciated mechanism of metformin leads to host VB12 deficiency by acting directly on gut bacteria to increase their VB12 uptake and consumption, and suggest that inter-host-microbe competition for nutrients may broadly impact human health and drug safety.
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Affiliation(s)
- Manyun Chen
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, P. R. China
- Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha, P. R. China
- Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, Changsha, P. R. China
- National Clinical Research Center for Geriatric Disorders, Changsha, P. R. China
| | - Yan Shu
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, P. R. China
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Maryland at Baltimore, Baltimore, MD, USA
| | - Qing Li
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, P. R. China
- Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha, P. R. China
- Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, Changsha, P. R. China
- National Clinical Research Center for Geriatric Disorders, Changsha, P. R. China
| | - Zhiqiang Kang
- Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou University, Zhengzhou, P. R. China
| | - Tao Liu
- Shenzhen Center for Chronic Disease Control and Prevention, Shenzhen, P. R. China
| | - Honghao Zhou
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, P. R. China
- Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha, P. R. China
- Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, Changsha, P. R. China
- National Clinical Research Center for Geriatric Disorders, Changsha, P. R. China
| | - Weihua Huang
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, P. R. China.
- Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha, P. R. China.
- Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, Changsha, P. R. China.
- National Clinical Research Center for Geriatric Disorders, Changsha, P. R. China.
| | - Wei Zhang
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, P. R. China.
- Institute of Clinical Pharmacology, Central South University, Hunan Key Laboratory of Pharmacogenetics, Changsha, P. R. China.
- Engineering Research Center of Applied Technology of Pharmacogenomics, Ministry of Education, Changsha, P. R. China.
- National Clinical Research Center for Geriatric Disorders, Changsha, P. R. China.
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10
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Pollet RM, Foley MH, Kumar SS, Elmore A, Jabara NT, Venkatesh S, Pereira GV, Martens EC, Koropatkin NM. Multiple TonB Homologs are Important for Carbohydrate Utilization by Bacteroides thetaiotaomicron. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.07.548152. [PMID: 37461508 PMCID: PMC10350073 DOI: 10.1101/2023.07.07.548152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/24/2023]
Abstract
The human gut microbiota is able to degrade otherwise undigestible polysaccharides, largely through the activity of the Bacteroides. Uptake of polysaccharides into Bacteroides is controlled by TonB-dependent transporters (TBDT) whose transport is energized by an inner membrane complex composed of the proteins TonB, ExbB, and ExbD. Bacteroides thetaiotaomicron (B. theta) encodes 11 TonB homologs which are predicted to be able to contact TBDTs to facilitate transport. However, it is not clear which TonBs are important for polysaccharide uptake. Using strains in which each of the 11 predicted tonB genes are deleted, we show that TonB4 (BT2059) is important but not essential for proper growth on starch. In the absence of TonB4, we observed an increase in abundance of TonB6 (BT2762) in the membrane of B. theta, suggesting functional redundancy of these TonB proteins. Growth of the single deletion strains on pectin galactan, chondroitin sulfate, arabinan, and levan suggests a similar functional redundancy of the TonB proteins. A search for highly homologous proteins across other Bacteroides species and recent work in B. fragilis suggests that TonB4 is widely conserved and may play a common role in polysaccharide uptake. However, proteins similar to TonB6 are found only in B. theta and closely related species suggesting that the functional redundancy of TonB4 and TonB6 may be limited across the Bacteroides. This study extends our understanding of the protein network required for polysaccharide utilization in B. theta and highlights differences in TonB complexes across Bacteroides species.
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Affiliation(s)
- Rebecca M Pollet
- Department of Chemistry, Vassar College, Poughkeepsie, NY, 12604, USA
- Biochemistry Program, Vassar College, Poughkeepsie, NY, 12604, USA
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Matthew H Foley
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Supriya Suresh Kumar
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Amanda Elmore
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Nisrine T Jabara
- Biochemistry Program, Vassar College, Poughkeepsie, NY, 12604, USA
| | - Sameeksha Venkatesh
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | | | - Eric C Martens
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Nicole M Koropatkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
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11
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Braun V, Ratliff AC, Celia H, Buchanan SK. Energization of Outer Membrane Transport by the ExbB ExbD Molecular Motor. J Bacteriol 2023; 205:e0003523. [PMID: 37219427 PMCID: PMC10294619 DOI: 10.1128/jb.00035-23] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023] Open
Abstract
The outer membranes (OM) of Gram-negative bacteria contain a class of proteins (TBDTs) that require energy for the import of nutrients and to serve as receptors for phages and protein toxins. Energy is derived from the proton motif force (pmf) of the cytoplasmic membrane (CM) through the action of three proteins, namely, TonB, ExbB, and ExbD, which are located in the CM and extend into the periplasm. The leaky phenotype of exbB exbD mutants is caused by partial complementation by homologous tolQ tolR. TonB, ExbB, and ExbD are genuine components of an energy transmission system from the CM into the OM. Mutant analyses, cross-linking experiments, and most recently X-ray and cryo-EM determinations were undertaken to arrive at a model that describes the energy transfer from the CM into the OM. These results are discussed in this paper. ExbB forms a pentamer with a pore inside, in which an ExbD dimer resides. This complex harvests the energy of the pmf and transmits it to TonB. TonB interacts with the TBDT at the TonB box, which triggers a conformational change in the TBDT that releases bound nutrients and opens the pore, through which nutrients pass into the periplasm. The structurally altered TBDT also changes the interactions of its periplasmic signaling domain with anti-sigma factors, with the consequence being that the sigma factors initiate transcription.
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Affiliation(s)
- Volkmar Braun
- Max-Planck-Institute for Biology, Department of Protein Evolution, Tübingen, Germany
| | - Anna C. Ratliff
- Laboratory of Molecular Biology, National Institute of Diabetes & Digestive & Kidney Diseases, NIH, Maryland, Bethesda, USA
| | - Herve Celia
- Laboratory of Molecular Biology, National Institute of Diabetes & Digestive & Kidney Diseases, NIH, Maryland, Bethesda, USA
| | - Susan K. Buchanan
- Laboratory of Molecular Biology, National Institute of Diabetes & Digestive & Kidney Diseases, NIH, Maryland, Bethesda, USA
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12
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Chan DCK, Josts I, Koteva K, Wright GD, Tidow H, Burrows LL. Interactions of TonB-dependent transporter FoxA with siderophores and antibiotics that affect binding, uptake, and signal transduction. Proc Natl Acad Sci U S A 2023; 120:e2221253120. [PMID: 37043535 PMCID: PMC10120069 DOI: 10.1073/pnas.2221253120] [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: 12/14/2022] [Accepted: 03/07/2023] [Indexed: 04/13/2023] Open
Abstract
The outer membrane of gram-negative bacteria prevents many antibiotics from reaching intracellular targets. However, some antimicrobials can take advantage of iron import transporters to cross this barrier. We showed previously that the thiopeptide antibiotic thiocillin exploits the nocardamine xenosiderophore transporter, FoxA, of the opportunistic pathogen Pseudomonas aeruginosa for uptake. Here, we show that FoxA also transports the xenosiderophore bisucaberin and describe at 2.5 Å resolution the crystal structure of bisucaberin bound to FoxA. Bisucaberin is distinct from other siderophores because it forms a 3:2 rather than 1:1 siderophore-iron complex. Mutations in a single extracellular loop of FoxA differentially affected nocardamine, thiocillin, and bisucaberin binding, uptake, and signal transduction. These results show that in addition to modulating ligand binding, the extracellular loops of siderophore transporters are of fundamental importance for controlling ligand uptake and its regulatory consequences, which have implications for the development of siderophore-antibiotic conjugates to treat difficult infections.
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Affiliation(s)
- Derek C. K. Chan
- David Braley Center for Antibiotic Discovery, McMaster University, Hamilton, ONL8S 4K1, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ONL8S 4K1, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 4K1, Canada
| | - Inokentijs Josts
- The Hamburg Advanced Research Center for Bioorganic Chemistry, Hamburg22761, Germany
- Department of Chemistry, Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg22761, Germany
| | - Kalinka Koteva
- David Braley Center for Antibiotic Discovery, McMaster University, Hamilton, ONL8S 4K1, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ONL8S 4K1, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 4K1, Canada
| | - Gerard D. Wright
- David Braley Center for Antibiotic Discovery, McMaster University, Hamilton, ONL8S 4K1, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ONL8S 4K1, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 4K1, Canada
| | - Henning Tidow
- The Hamburg Advanced Research Center for Bioorganic Chemistry, Hamburg22761, Germany
- Department of Chemistry, Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg22761, Germany
| | - Lori L. Burrows
- David Braley Center for Antibiotic Discovery, McMaster University, Hamilton, ONL8S 4K1, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, ONL8S 4K1, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ONL8S 4K1, Canada
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13
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Peukert C, Gasser V, Orth T, Fritsch S, Normant V, Cunrath O, Schalk IJ, Brönstrup M. Trojan Horse Siderophore Conjugates Induce Pseudomonas aeruginosa Suicide and Qualify the TonB Protein as a Novel Antibiotic Target. J Med Chem 2023; 66:553-576. [PMID: 36548006 PMCID: PMC9841981 DOI: 10.1021/acs.jmedchem.2c01489] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Indexed: 12/24/2022]
Abstract
Rising infection rates with multidrug-resistant pathogens calls for antibiotics with novel modes of action. Herein, we identify the inner membrane protein TonB, a motor of active uptake in Gram-negative bacteria, as a novel target in antimicrobial therapy. The interaction of the TonB box of outer membrane transporters with TonB is crucial for the internalization of essential metabolites. We designed TonB box peptides and coupled them with synthetic siderophores in order to facilitate their uptake into bacteria in up to 32 synthetic steps. Three conjugates repressed the growth of Pseudomonas aeruginosa cells unable to produce their own siderophores, with minimal inhibitory concentrations between 0.1 and 0.5 μM. The transporters mediating uptake of these compounds were identified as PfeA and PirA. The study illustrates a variant of cellular suicide where a transporter imports its own inhibitor and demonstrates that artificial siderophores can import cargo with molecular weights up to 4 kDa.
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Affiliation(s)
- Carsten Peukert
- Department
of Chemical Biology, Helmholtz Centre for
Infection Research, Inhoffenstraße 7, 38124 Braunschweig, Germany
| | - Véronique Gasser
- CNRS, University
of Strasbourg, UMR7242, ESBS, Boulevard Sébastien Brant, F-67412 Illkirch, Strasbourg, France
| | - Till Orth
- Department
of Chemical Biology, Helmholtz Centre for
Infection Research, Inhoffenstraße 7, 38124 Braunschweig, Germany
| | - Sarah Fritsch
- CNRS, University
of Strasbourg, UMR7242, ESBS, Boulevard Sébastien Brant, F-67412 Illkirch, Strasbourg, France
| | - Vincent Normant
- CNRS, University
of Strasbourg, UMR7242, ESBS, Boulevard Sébastien Brant, F-67412 Illkirch, Strasbourg, France
| | - Olivier Cunrath
- CNRS, University
of Strasbourg, UMR7242, ESBS, Boulevard Sébastien Brant, F-67412 Illkirch, Strasbourg, France
| | - Isabelle J. Schalk
- CNRS, University
of Strasbourg, UMR7242, ESBS, Boulevard Sébastien Brant, F-67412 Illkirch, Strasbourg, France
| | - Mark Brönstrup
- Department
of Chemical Biology, Helmholtz Centre for
Infection Research, Inhoffenstraße 7, 38124 Braunschweig, Germany
- German
Center for Infection Research (DZIF), Site Hannover-Braunschweig, 38124 Braunschweig, Germany
- Center for
Biomolecular Drug Research (BMWZ), Schneiderberg 38, 30167 Hannover, Germany
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14
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Dong Y, Xu M, Wan X, Zhao D, Geng J, Huang H, Jiang M, Lu C, Liu Y. TonB systems are required for Aeromonas hydrophila motility by controlling the secretion of flagellin. Microbes Infect 2023; 25:105038. [PMID: 35963567 DOI: 10.1016/j.micinf.2022.105038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2022] [Revised: 08/03/2022] [Accepted: 08/03/2022] [Indexed: 02/04/2023]
Abstract
The TonB system is required for the active transport of iron compounds across the outer membrane in Gram-negative bacteria. Our previous data indicated that three TonB systems act coordinately to contribute to the motility of Aeromonas hydrophila NJ-35. In this study, we found that flagellum biogenesis was defective in the ΔtonB123 mutant. Subcellular localization indicated that the flagellin subunits FlaA and FlaB were trapped in the cytoplasm of ΔtonB123 mutant with reduced molecular mass. Overexpression of FlaA or FlaB in the ΔtonB123 mutant was unable to restore the secretion of flagellin subunits. Further investigation demonstrated that flagellins in the ΔtonB123 mutant showed a weak affinity for the flagellin-specific chaperone FliS, which is necessary for the export of flagellins. Deglycosylation analysis indicated that flagellins in the cytoplasm of the ΔtonB123 mutant were almost nonglycosylated. Our data suggested that disruption of tonB123 impairs the formation of flagella by inhibiting flagellin glycosylation and decreasing the binding affinity of flagellin for the chaperone FliS. Taken together, our findings indicate a new role of the TonB system in flagellar biogenesis in A. hydrophila.
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Affiliation(s)
- Yuhao Dong
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Meng Xu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Xihe Wan
- Institute of Oceanology and Marine Fisheries, Nantong, 226007, Jiangsu, China
| | - Dan Zhao
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Jinzhu Geng
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Hao Huang
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Mingguo Jiang
- Guangxi Key Laboratory for Polysaccharide Materials and Modifications, School of Marine Sciences and Biotechnology, Guangxi University for Nationalities, Nanning, 530008, Guangxi, China
| | - Chengping Lu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China
| | - Yongjie Liu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, Jiangsu, China.
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15
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Schalk IJ, Perraud Q. Pseudomonas aeruginosa and its multiple strategies to access iron. Environ Microbiol 2022; 25:811-831. [PMID: 36571575 DOI: 10.1111/1462-2920.16328] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 12/21/2022] [Indexed: 12/27/2022]
Abstract
Pseudomonas aeruginosa is a ubiquitous bacterium found in many natural and man-made environments. It is also a pathogen for plants, animals, and humans. As for almost all living organisms, iron is an essential nutrient for the growth of P. aeruginosa. The bacterium has evolved complex systems to access iron and maintain its homeostasis to survive in diverse natural and dynamic host environments. To access ferric iron, P. aeruginosa is able to produce two siderophores (pyoverdine and pyochelin), as well as use a variety of siderophores produced by other bacteria (mycobactins, enterobactin, ferrioxamine, ferrichrome, vibriobactin, aerobactin, rhizobactin and schizokinen). Furthermore, it can also use citrate, in addition to catecholamine neuromediators and plant-derived mono catechols, as siderophores. The P. aeruginosa genome also encodes three heme-uptake pathways (heme being an iron source) and one ferrous iron acquisition pathway. This review aims to summarize current knowledge concerning the molecular mechanisms involved in all the iron and heme acquisition strategies used by P. aeruginosa.
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Affiliation(s)
- Isabelle J Schalk
- CNRS, UMR7242, ESBS, Strasbourg, France.,University of Strasbourg, UMR7242, ESBS, Strasbourg, France
| | - Quentin Perraud
- CNRS, UMR7242, ESBS, Strasbourg, France.,University of Strasbourg, UMR7242, ESBS, Strasbourg, France
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16
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Shisaka Y, Shoji O. Bridging the gap: Unveiling novel functions of a bacterial haem-acquisition protein capturing diverse synthetic porphyrinoids. Coord Chem Rev 2022. [DOI: 10.1016/j.ccr.2022.214793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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17
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Moynié L, Hoegy F, Milenkovic S, Munier M, Paulen A, Gasser V, Faucon AL, Zill N, Naismith JH, Ceccarelli M, Schalk IJ, Mislin GLA. Hijacking of the Enterobactin Pathway by a Synthetic Catechol Vector Designed for Oxazolidinone Antibiotic Delivery in Pseudomonas aeruginosa. ACS Infect Dis 2022; 8:1894-1904. [PMID: 35881068 DOI: 10.1021/acsinfecdis.2c00202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Enterobactin (ENT) is a tris-catechol siderophore used to acquire iron by multiple bacterial species. These ENT-dependent iron uptake systems have often been considered as potential gates in the bacterial envelope through which one can shuttle antibiotics (Trojan horse strategy). In practice, siderophore analogues containing catechol moieties have shown promise as vectors to which antibiotics may be attached. Bis- and tris-catechol vectors (BCVs and TCVs, respectively) were shown using structural biology and molecular modeling to mimic ENT binding to the outer membrane transporter PfeA in Pseudomonas aeruginosa. TCV but not BCV appears to cross the outer membrane via PfeA when linked to an antibiotic (linezolid). TCV is therefore a promising vector for Trojan horse strategies against P. aeruginosa, confirming the ENT-dependent iron uptake system as a gate to transport antibiotics into P. aeruginosa cells.
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Affiliation(s)
- Lucile Moynié
- The Rosalind Franklin Institute, Harwell Campus, Oxfordshire OX11 0QS, U.K
| | - Françoise Hoegy
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
| | - Stefan Milenkovic
- Department of Physics, University of Cagliari, 09042 Monserrato, Italy
| | - Mathilde Munier
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
| | - Aurélie Paulen
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
| | - Véronique Gasser
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
| | - Aline L Faucon
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
| | - Nicolas Zill
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
| | - James H Naismith
- The Rosalind Franklin Institute, Harwell Campus, Oxfordshire OX11 0QS, U.K.,Division of Structural Biology, Wellcome Trust Centre of Human Genomics, 7 Roosevelt Drive, Oxford OX3 7BN, U.K
| | - Matteo Ceccarelli
- Department of Physics, University of Cagliari, 09042 Monserrato, Italy.,IOM/CNR, Sezione di Cagliari, University of Cagliari, 09042 Monserrato, Italy
| | - Isabelle J Schalk
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
| | - Gaëtan L A Mislin
- CNRS, UMR7242 Biotechnologie et Signalisation Cellulaire, 300 Boulevard Sébastien Brant, F-67412 Illkirch, France.,Université de Strasbourg, Institut de Recherche de l'Ecole de Biotechnologie de Strasbourg (IREBS), 300 Boulevard Sébastien Brant, F-67412 Illkirch, France
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18
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Fritsch S, Gasser V, Peukert C, Pinkert L, Kuhn L, Perraud Q, Normant V, Brönstrup M, Schalk IJ. Uptake Mechanisms and Regulatory Responses to MECAM- and DOTAM-Based Artificial Siderophores and Their Antibiotic Conjugates in Pseudomonas aeruginosa. ACS Infect Dis 2022; 8:1134-1146. [PMID: 35500104 DOI: 10.1021/acsinfecdis.2c00049] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The development of new antibiotics against Gram-negative bacteria has to deal with the low permeability of the outer membrane. This obstacle can be overcome by utilizing siderophore-dependent iron uptake pathways as entrance routes for antibiotic uptake. Iron-chelating siderophores are actively imported by bacteria, and their conjugation to antibiotics allows smuggling the latter into bacterial cells. Synthetic siderophore mimetics based on MECAM (1,3,5-N,N',N″-tris-(2,3-dihydroxybenzoyl)-triaminomethylbenzene) and DOTAM (1,4,7,10-tetrakis(carbamoylmethyl)-1,4,7,10-tetraazacyclododecane) cores, both chelating iron via catechol groups, have been recently applied as versatile carriers of functional cargo. In the present study, we show that MECAM and the MECAM-ampicillin conjugate 3 transport iron into Pseudomonas aeruginosa cells via the catechol-type outer membrane transporters PfeA and PirA and DOTAM solely via PirA. Differential proteomics and quantitative real-time polymerase chain reaction (qRT-PCR) showed that MECAM import induced the expression of pfeA, whereas 3 led to an increase in the expression of pfeA and ampc, a gene conferring ampicillin resistance. The presence of DOTAM did not induce the expression of pirA but upregulated the expression of two zinc transporters (cntO and PA0781), pointing out that bacteria become zinc starved in the presence of this compound. Iron uptake experiments with radioactive 55Fe demonstrated that import of this nutrient by MECAM and DOTAM was as efficient as with the natural siderophore enterobactin. The study provides a functional validation for DOTAM- and MECAM-based artificial siderophore mimetics as vehicles for the delivery of cargo into Gram-negative bacteria.
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Affiliation(s)
- Sarah Fritsch
- CNRS, University of Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67412 Illkirch, Strasbourg 67070, France
| | - Véronique Gasser
- CNRS, University of Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67412 Illkirch, Strasbourg 67070, France
| | - Carsten Peukert
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, Braunschweig 38124, Germany
| | - Lukas Pinkert
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, Braunschweig 38124, Germany
| | - Lauriane Kuhn
- Plateforme Proteomique Strasbourg-Esplanade, Institut de Biologie Moléculaire et Cellulaire, CNRS, FR1589, 15 rue Descartes, Strasbourg Cedex F-67084, France
| | - Quentin Perraud
- CNRS, University of Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67412 Illkirch, Strasbourg 67070, France
| | - Vincent Normant
- CNRS, University of Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67412 Illkirch, Strasbourg 67070, France
| | - Mark Brönstrup
- Department of Chemical Biology, Helmholtz Centre for Infection Research, Inhoffenstrasse 7, Braunschweig 38124, Germany
- German Center for Infection Research (DZIF), Site Hannover-Braunschweig, Braunschweig 38124, Germany
- Center of Biomolecular Drug Research (BMWZ), Leibniz Universität, Hannover 30159, Germany
| | - Isabelle J. Schalk
- CNRS, University of Strasbourg, UMR7242, ESBS, Bld Sébastien Brant, F-67412 Illkirch, Strasbourg 67070, France
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19
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Saha I, Chakraborty S, Agarwal S, Mukherjee P, Ghosh B, Dasgupta J. Mechanistic insights of ABC importer HutCD involved in heme internalization by Vibrio cholerae. Sci Rep 2022; 12:7152. [PMID: 35504999 PMCID: PMC9065009 DOI: 10.1038/s41598-022-11213-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 03/24/2022] [Indexed: 11/10/2022] Open
Abstract
Heme internalization by pathogenic bacteria inside a human host to accomplish the requirement of iron for important cellular processes is of paramount importance. Despite this, the mechanism of heme import by the ATP-binding-cassette (ABC) transporter HutCD in Vibrio cholerae remains unexplored. We have performed biochemical studies on ATPase HutD and its mutants, along with molecular modelling, docking and unbiased all-atom MD simulations on lipid-solvated models of permease-ATPase complex HutCD. The results demonstrated mechanisms of ATP binding/hydrolysis and trapped transient and global conformational changes in HutCD, necessary for heme internalization. ATPase HutD forms a dimer, independent of the permease HutC. Each HutD monomer canonically binds ATP in a 1:1 stoichiometry. MD simulations demonstrated that a rotational motion of HutC dimer occurs synchronously with the inter-dimeric D-loop interactions of HutDs. F151 of TM4–TM5 loop of HutC, packs with ATP and Y15 of HutD, initiating ‘cytoplasmic gate opening’ which mimics an ‘outward-facing’ to ‘inward-facing’ conformational switching upon ATP hydrolysis. The simulation on ‘inward-facing’ HutCD culminates to an ‘occluded’ state. The simulation on heme-docked HutCD indicated that the event of heme release occurs in ATP-free ‘inward-facing’ state. Gradual conformational changes of the TM5 helices of HutC towards the ‘occluded’ state facilitate ejection of heme.
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Affiliation(s)
- Indrila Saha
- Department of Biotechnology, St. Xavier's College (Autonomous), 30, Mother Teresa Sarani, Kolkata, 700016, India
| | - Shrestha Chakraborty
- Department of Biotechnology, St. Xavier's College (Autonomous), 30, Mother Teresa Sarani, Kolkata, 700016, India
| | - Shubhangi Agarwal
- Department of Biotechnology, St. Xavier's College (Autonomous), 30, Mother Teresa Sarani, Kolkata, 700016, India.,Weill Cornell Medicine, Department of Anesthesiology, 1300 York Ave, New York, NY, 10065, USA
| | - Peeali Mukherjee
- Department of Biotechnology, St. Xavier's College (Autonomous), 30, Mother Teresa Sarani, Kolkata, 700016, India
| | - Biplab Ghosh
- Macromolecular Crystallography Section, Beamline Development & Application Section, Bhabha Atomic Research Center, Trombay, Mumbai, 400085, India.
| | - Jhimli Dasgupta
- Department of Biotechnology, St. Xavier's College (Autonomous), 30, Mother Teresa Sarani, Kolkata, 700016, India.
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20
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Sy BM, Tree JJ. The Small RNA CyaR Activates Translation of the Outer Membrane Haem Receptor chuA in Enterohemorrhagic Escherichia coli. Front Microbiol 2022; 13:821196. [PMID: 35422774 PMCID: PMC9002310 DOI: 10.3389/fmicb.2022.821196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 02/10/2022] [Indexed: 12/22/2022] Open
Abstract
To sense the transition from environment to host, bacteria use a range of environmental cues to control expression of virulence genes. Iron is tightly sequestered in host tissues and in the human pathogen enterohemorrhagic Escherichia coli (EHEC) iron-limitation induces transcription of the outer membrane haem transporter encoded by chuAS. ChuA expression is post-transcriptionally activated at 37°C by a FourU RNA thermometer ensuring that the haem receptor is only expressed under low iron, high temperature conditions that indicate the host. Here we demonstrate that expression of chuA is also independently regulated by the cAMP-responsive small RNA (sRNA) CyaR and transcriptional terminator Rho. These results indicate that chuAS expression is regulated at the transcription initiation, transcript elongation, and translational level. We speculate that additional sensing of the gluconeogenic environment allows further precision in determining when EHEC is at the gastrointestinal epithelium of the host. With previous studies, it appears that the chuAS transcript is controlled by eight regulatory inputs that control expression through six different transcriptional and post-transcriptional mechanisms. The results highlight the ability of regulatory sRNAs to integrate multiple environmental signals into a layered hierarchy of signal input.
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Affiliation(s)
- Brandon M Sy
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Jai J Tree
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, NSW, Australia
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21
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Biou V, Adaixo RJD, Chami M, Coureux PD, Laurent B, Enguéné VYN, de Amorim GC, Izadi-Pruneyre N, Malosse C, Chamot-Rooke J, Stahlberg H, Delepelaire P. Structural and molecular determinants for the interaction of ExbB from Serratia marcescens and HasB, a TonB paralog. Commun Biol 2022; 5:355. [PMID: 35418619 PMCID: PMC9008036 DOI: 10.1038/s42003-022-03306-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 03/22/2022] [Indexed: 01/20/2023] Open
Abstract
ExbB and ExbD are cytoplasmic membrane proteins that associate with TonB to convey the energy of the proton-motive force to outer membrane receptors in Gram-negative bacteria for iron uptake. The opportunistic pathogen Serratia marcescens (Sm) possesses both TonB and a heme-specific TonB paralog, HasB. ExbBSm has a long periplasmic extension absent in other bacteria such as E. coli (Ec). Long ExbB's are found in several genera of Alphaproteobacteria, most often in correlation with a hasB gene. We investigated specificity determinants of ExbBSm and HasB. We determined the cryo-EM structures of ExbBSm and of the ExbB-ExbDSm complex from S. marcescens. ExbBSm alone is a stable pentamer, and its complex includes two ExbD monomers. We showed that ExbBSm extension interacts with HasB and is involved in heme acquisition and we identified key residues in the membrane domain of ExbBSm and ExbBEc, essential for function and likely involved in the interaction with TonB/HasB. Our results shed light on the class of inner membrane energy machinery formed by ExbB, ExbD and HasB.
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Affiliation(s)
- Valérie Biou
- grid.508487.60000 0004 7885 7602Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, Université de Paris, UMR 7099 CNRS, F-75005 Paris, France ,grid.450875.b0000 0004 0643 538XInstitut de Biologie Physico-Chimique, F-75005 Paris, France
| | - Ricardo Jorge Diogo Adaixo
- grid.6612.30000 0004 1937 0642Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Mohamed Chami
- grid.6612.30000 0004 1937 0642Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, CH-4058 Basel, Switzerland
| | - Pierre-Damien Coureux
- grid.10877.390000000121581279Laboratoire de Biologie Structurale de la Cellule, BIOC, UMR7654 CNRS/Ecole polytechnique, Palaiseau, France
| | - Benoist Laurent
- grid.450875.b0000 0004 0643 538XInstitut de Biologie Physico-Chimique, F-75005 Paris, France ,grid.508487.60000 0004 7885 7602Plateforme de Bioinformatique, Université de Paris, FRC 550 CNRS, F-75005 Paris, France
| | - Véronique Yvette Ntsogo Enguéné
- grid.508487.60000 0004 7885 7602Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, Université de Paris, UMR 7099 CNRS, F-75005 Paris, France ,grid.450875.b0000 0004 0643 538XInstitut de Biologie Physico-Chimique, F-75005 Paris, France ,grid.5335.00000000121885934Present Address: Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1GA UK
| | - Gisele Cardoso de Amorim
- Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, C3BI, Institut Pasteur, CNRS UMR3528, CNRS, USR3756 Paris, France ,grid.8536.80000 0001 2294 473XPresent Address: Instituto de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ Brasil
| | - Nadia Izadi-Pruneyre
- Structural Bioinformatics Unit, Department of Structural Biology and Chemistry, C3BI, Institut Pasteur, CNRS UMR3528, CNRS, USR3756 Paris, France
| | - Christian Malosse
- grid.428999.70000 0001 2353 6535Mass Spectrometry for Biology Unit, CNRS USR 2000, Institut Pasteur, 75015 Paris, France
| | - Julia Chamot-Rooke
- grid.428999.70000 0001 2353 6535Mass Spectrometry for Biology Unit, CNRS USR 2000, Institut Pasteur, 75015 Paris, France
| | - Henning Stahlberg
- grid.6612.30000 0004 1937 0642Center for Cellular Imaging and NanoAnalytics, Biozentrum, University of Basel, Mattenstrasse 26, CH-4058 Basel, Switzerland ,grid.9851.50000 0001 2165 4204Present Address: Centre d’imagerie Dubochet UNIL-EPFL-UNIGE & Laboratoire de microscopie électronique biologique UNIL-EPFL, Lausanne, Switzerland
| | - Philippe Delepelaire
- grid.508487.60000 0004 7885 7602Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, Université de Paris, UMR 7099 CNRS, F-75005 Paris, France ,grid.450875.b0000 0004 0643 538XInstitut de Biologie Physico-Chimique, F-75005 Paris, France
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22
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Abstract
The Ton complex is a molecular motor at the inner membrane of Gram-negative bacteria that uses a proton gradient to apply forces on outer membrane (OM) proteins to permit active transport of nutrients into the periplasmic space. Recently, the structure of the ExbB–ExbD subcomplex was determined in several bacterial species, but the complete structure and stoichiometry of TonB have yet to be determined. The C-terminal end of TonB is known to cross the periplasm and interact with TonB-dependent outer membrane transport proteins with high affinity. Yet despite having significant knowledge of these transport proteins, it is not clear how the Ton motor opens a pathway across the outer membrane for nutrient import. Additionally, the mechanism by which energy is harnessed from the inner membrane subcomplex and transduced to the outer membrane via TonB is not well understood. In this review, we will discuss the gaps in the knowledge about the complete structure of the Ton motor complex and the relationship between ion flow used to generate mechanical work at the outer membrane and the nutrient transport process.
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23
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Webby MN, Williams-Jones DP, Press C, Kleanthous C. Force-Generation by the Trans-Envelope Tol-Pal System. Front Microbiol 2022; 13:852176. [PMID: 35308353 PMCID: PMC8928145 DOI: 10.3389/fmicb.2022.852176] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 01/26/2022] [Indexed: 11/13/2022] Open
Abstract
The Tol-Pal system spans the cell envelope of Gram-negative bacteria, transducing the potential energy of the proton motive force (PMF) into dissociation of the TolB-Pal complex at the outer membrane (OM), freeing the lipoprotein Pal to bind the cell wall. The primary physiological role of Tol-Pal is to maintain OM integrity during cell division through accumulation of Pal molecules at division septa. How the protein complex couples the PMF at the inner membrane into work at the OM is unknown. The effectiveness of this trans-envelope energy transduction system is underscored by the fact that bacteriocins and bacteriophages co-opt Tol-Pal as part of their import/infection mechanisms. Mechanistic understanding of this process has been hindered by a lack of structural data for the inner membrane TolQ-TolR stator, of its complexes with peptidoglycan (PG) and TolA, and of how these elements combined power events at the OM. Recent studies on the homologous stators of Ton and Mot provide a starting point for understanding how Tol-Pal works. Here, we combine ab initio protein modeling with previous structural data on sub-complexes of Tol-Pal as well as mutagenesis, crosslinking, co-conservation analysis and functional data. Through this composite pooling of in silico, in vitro, and in vivo data, we propose a mechanism for force generation in which PMF-driven rotary motion within the stator drives conformational transitions within a long TolA helical hairpin domain, enabling it to reach the TolB-Pal complex at the OM.
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Affiliation(s)
| | | | | | - Colin Kleanthous
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
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24
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Vincent MS, Comas Hervada C, Sebban-Kreuzer C, Le Guenno H, Chabalier M, Kosta A, Guerlesquin F, Mignot T, McBride MJ, Cascales E, Doan T. Dynamic proton-dependent motors power type IX secretion and gliding motility in Flavobacterium. PLoS Biol 2022; 20:e3001443. [PMID: 35333857 PMCID: PMC8986121 DOI: 10.1371/journal.pbio.3001443] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 04/06/2022] [Accepted: 03/01/2022] [Indexed: 02/06/2023] Open
Abstract
Motile bacteria usually rely on external apparatus like flagella for swimming or pili for twitching. By contrast, gliding bacteria do not rely on obvious surface appendages to move on solid surfaces. Flavobacterium johnsoniae and other bacteria in the Bacteroidetes phylum use adhesins whose movement on the cell surface supports motility. In F. johnsoniae, secretion and helicoidal motion of the main adhesin SprB are intimately linked and depend on the type IX secretion system (T9SS). Both processes necessitate the proton motive force (PMF), which is thought to fuel a molecular motor that comprises the GldL and GldM cytoplasmic membrane proteins. Here, we show that F. johnsoniae gliding motility is powered by the pH gradient component of the PMF. We further delineate the interaction network between the GldLM transmembrane helices (TMHs) and show that conserved glutamate residues in GldL TMH2 are essential for gliding motility, although having distinct roles in SprB secretion and motion. We then demonstrate that the PMF and GldL trigger conformational changes in the GldM periplasmic domain. We finally show that multiple GldLM complexes are distributed in the membrane, suggesting that a network of motors may be present to move SprB along a helical path on the cell surface. Altogether, our results provide evidence that GldL and GldM assemble dynamic membrane channels that use the proton gradient to power both T9SS-dependent secretion of SprB and its motion at the cell surface. Motile bacteria usually rely on external apparatus like flagella or pili, but gliding bacteria do not rely on obvious surface appendages for their movement. This study shows that bacteria in the phylum Bacteroidetes use proton-dependent motors to power protein secretion and gliding motility.
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Affiliation(s)
- Maxence S. Vincent
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Caterina Comas Hervada
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Corinne Sebban-Kreuzer
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Hugo Le Guenno
- Microscopy Core Facility, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université, Marseille, France
| | - Maïalène Chabalier
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Artemis Kosta
- Microscopy Core Facility, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université, Marseille, France
| | - Françoise Guerlesquin
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
| | - Tâm Mignot
- Laboratoire de Chimie Bactérienne, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7283, Marseille, France
| | - Mark J. McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, United States of America
| | - Eric Cascales
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
- * E-mail: (EC); (TD)
| | - Thierry Doan
- Laboratoire d’Ingénierie des Systèmes Macromoléculaires, Institut de Microbiologie, Bioénergies et Biotechnologie, Aix-Marseille Université – CNRS UMR7255, Marseille, France
- * E-mail: (EC); (TD)
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25
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Nishikino T, Sagara Y, Terashima H, Homma M, Kojima S. Hoop-like role of the cytosolic interface helix in Vibrio PomA, an ion-conducting membrane protein, in the bacterial flagellar motor. J Biochem 2022; 171:443-450. [PMID: 35015887 DOI: 10.1093/jb/mvac001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 01/04/2022] [Indexed: 11/13/2022] Open
Abstract
Vibrio has a polar flagellum driven by sodium ions for swimming. The force-generating stator unit consists of PomA and PomB. PomA contains four-transmembrane regions and a cytoplasmic domain of approximately 100 residues which interacts with the rotor protein, FliG, to be important for the force generation of rotation. The three-dimensional structure of the stator shows that the cytosolic interface (CI) helix of PomA is located parallel to the inner membrane. In this study, we investigated the function of CI helix and its role as stator. Systematic proline mutagenesis showed that residues K64, F66, and M67 were important for this function. The mutant stators did not assemble around the rotor. Moreover, the growth defect caused by PomB plug deletion was suppressed by these mutations. We speculate that the mutations affect the structure of the helices extending from TM3 and TM4 and reduce the structural stability of the stator complex. This study suggests that the helices parallel to the inner membrane play important roles in various processes, such as the hoop-like function in securing the stability of the stator complex and the ion conduction pathway, which may lead to the elucidation of the ion permeation and assembly mechanism of the stator.
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Affiliation(s)
- Tatsuro Nishikino
- Institute for protein research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yugo Sagara
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Hiroyuki Terashima
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan.,Department of bacteriology, Institute of Tropical Medicine (NEKKEN), Nagasaki University, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan
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26
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Rieu M, Krutyholowa R, Taylor NMI, Berry RM. A new class of biological ion-driven rotary molecular motors with 5:2 symmetry. Front Microbiol 2022; 13:948383. [PMID: 35992645 PMCID: PMC9389320 DOI: 10.3389/fmicb.2022.948383] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 07/04/2022] [Indexed: 11/15/2022] Open
Abstract
Several new structures of three types of protein complexes, obtained by cryo-electron microscopy (cryo-EM) and published between 2019 and 2021, identify a new family of natural molecular wheels, the "5:2 rotary motors." These span the cytoplasmic membranes of bacteria, and their rotation is driven by ion flow into the cell. They consist of a pentameric wheel encircling a dimeric axle within the cytoplasmic membrane of both Gram-positive and gram-negative bacteria. The axles extend into the periplasm, and the wheels extend into the cytoplasm. Rotation of these wheels has never been observed directly; it is inferred from the symmetry of the complexes and from the roles they play within the larger systems that they are known to power. In particular, the new structure of the stator complex of the Bacterial Flagellar Motor, MotA5B2, is consistent with a "wheels within wheels" model of the motor. Other 5:2 rotary motors are believed to share the core rotary function and mechanism, driven by ion-motive force at the cytoplasmic membrane. Their structures diverge in their periplasmic and cytoplasmic parts, reflecting the variety of roles that they perform. This review focuses on the structures of 5:2 rotary motors and their proposed mechanisms and functions. We also discuss molecular rotation in general and its relation to the rotational symmetry of molecular complexes.
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Affiliation(s)
- Martin Rieu
- Department of Physics, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building University of Oxford, Oxford, United Kingdom
| | - Roscislaw Krutyholowa
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Nicholas M. I. Taylor
- Novo Nordisk Foundation Center for Protein Research, University of Copenhagen, Copenhagen, Denmark
- Nicholas M. I. Taylor,
| | - Richard M. Berry
- Department of Physics, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, Dorothy Crowfoot Hodgkin Building University of Oxford, Oxford, United Kingdom
- *Correspondence: Richard M. Berry,
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27
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Troman LA, Collinson I. Pushing the Envelope: The Mysterious Journey Through the Bacterial Secretory Machinery, and Beyond. Front Microbiol 2021; 12:782900. [PMID: 34917061 PMCID: PMC8669966 DOI: 10.3389/fmicb.2021.782900] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Accepted: 11/09/2021] [Indexed: 11/20/2022] Open
Abstract
Gram-negative bacteria are contained by an envelope composed of inner and outer-membranes with the peptidoglycan (PG) layer between them. Protein translocation across the inner membrane for secretion, or insertion into the inner membrane is primarily conducted using the highly conserved, hourglass-shaped channel, SecYEG: the core-complex of the Sec translocon. This transport process is facilitated by interactions with ancillary subcomplex SecDF-YajC (secretion) and YidC (insertion) forming the holo-translocon (HTL). This review recaps the transport process across the inner-membrane and then further explores how delivery and folding into the periplasm or outer-membrane is achieved. It seems very unlikely that proteins are jettisoned into the periplasm and left to their own devices. Indeed, chaperones such as SurA, Skp, DegP are known to play a part in protein folding, quality control and, if necessary degradation. YfgM and PpiD, by their association at the periplasmic surface of the Sec machinery, most probably are also involved in some way. Yet, it is not entirely clear how outer-membrane proteins are smuggled past the proteases and across the PG to the barrel-assembly machinery (BAM) and their final destination. Moreover, how can this be achieved, as is thought, without the input of energy? Recently, we proposed that the Sec and BAM translocons interact with one another, and most likely other factors, to provide a conduit to the periplasm and the outer-membrane. As it happens, numerous other specialized proteins secretion systems also form trans-envelope structures for this very purpose. The direct interaction between components across the envelope raises the prospect of energy coupling from the inner membrane for active transport to the outer-membrane. Indeed, this kind of long-range energy coupling through large inter-membrane assemblies occurs for small molecule import (e.g., nutrient import by the Ton complex) and export (e.g., drug efflux by the AcrAB-TolC complex). This review will consider this hypothetical prospect in the context of outer-membrane protein biogenesis.
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Affiliation(s)
| | - Ian Collinson
- School of Biochemistry, University of Bristol, Bristol, United Kingdom
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28
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Homma M, Nishikino T, Kojima S. Achievements in bacterial flagellar research with focus on Vibrio species. Microbiol Immunol 2021; 66:75-95. [PMID: 34842307 DOI: 10.1111/1348-0421.12954] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 11/24/2021] [Accepted: 11/25/2021] [Indexed: 12/01/2022]
Abstract
In 1980's, the most genes involved in the bacterial flagellar function and formation had been isolated though many of their functions or roles were not clarified. Bacterial flagella are the primary locomotive organ and are not necessary for growing in vitro but are probably essential for living in natural condition and are involved in the pathogenicity. In vitro, the flagella-deficient strains can grow at rates similar to wild-type strains. More than 50 genes are responsible for flagellar function, and the flagellum is constructed by more than 20 structural proteins. The maintenance cost of flagellum is high as several genes are required for its development. The fact that it evolved as a motor organ even with such the high cost shows that the motility is indispensable to survive under the harsh environment of Earth. In this review, we focus on flagella-related research conducted by the authors for about 40 years and flagellar research focused on Vibrio spp. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University
| | | | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University
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29
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Fujita M, Yano S, Shibata K, Kondo M, Hishiyama S, Kamimura N, Masai E. Functional roles of multiple Ton complex genes in a Sphingobium degrader of lignin-derived aromatic compounds. Sci Rep 2021; 11:22444. [PMID: 34789769 PMCID: PMC8599685 DOI: 10.1038/s41598-021-01756-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 10/27/2021] [Indexed: 01/04/2023] Open
Abstract
TonB-dependent transporters (TBDTs) mediate outer membrane transport of nutrients using the energy derived from proton motive force transmitted from the TonB–ExbB–ExbD complex localized in the inner membrane. Recently, we discovered ddvT encoding a TBDT responsible for the uptake of a 5,5-type lignin-derived dimer in Sphingobium sp. strain SYK-6. Furthermore, overexpression of ddvT in an SYK-6-derivative strain enhanced its uptake capacity, improving the rate of platform chemical production. Thus, understanding the uptake system of lignin-derived aromatics is fundamental for microbial conversion-based lignin valorization. Here we examined whether multiple tonB-, exbB-, and exbD-like genes in SYK-6 contribute to the outer membrane transport of lignin-derived aromatics. The disruption of tonB2–6 and exbB3 did not reduce the capacity of SYK-6 to convert or grow on lignin-derived aromatics. In contrast, the introduction of the tonB1–exbB1–exbD1–exbD2 operon genes into SYK-6, which could not be disrupted, promoted the conversion of β-O-4-, β-5-, β-1-, β-β-, and 5,5-type dimers and monomers, such as ferulate, vanillate, syringate, and protocatechuate. These results suggest that TonB-dependent uptake involving the tonB1 operon genes is responsible for the outer membrane transport of the above aromatics. Additionally, exbB2/tolQ and exbD3/tolR were suggested to constitute the Tol-Pal system that maintains the outer membrane integrity.
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Affiliation(s)
- Masaya Fujita
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan.,Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki, Japan
| | - Shodai Yano
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan
| | - Koki Shibata
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan
| | - Mizuki Kondo
- Center for Integrated Technology Support, Nagaoka University of Technology, Nagaoka, Niigata, Japan
| | - Shojiro Hishiyama
- Forestry and Forest Products Research Institute, Tsukuba, Ibaraki, Japan
| | - Naofumi Kamimura
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan
| | - Eiji Masai
- Department of Bioengineering, Nagaoka University of Technology, Nagaoka, Niigata, 940-2188, Japan.
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30
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Acquisition of ionic copper by the bacterial outer membrane protein OprC through a novel binding site. PLoS Biol 2021; 19:e3001446. [PMID: 34762655 PMCID: PMC8610252 DOI: 10.1371/journal.pbio.3001446] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 11/23/2021] [Accepted: 10/18/2021] [Indexed: 11/19/2022] Open
Abstract
Copper, while toxic in excess, is an essential micronutrient in all kingdoms of life due to its essential role in the structure and function of many proteins. Proteins mediating ionic copper import have been characterised in detail for eukaryotes, but much less so for prokaryotes. In particular, it is still unclear whether and how gram-negative bacteria acquire ionic copper. Here, we show that Pseudomonas aeruginosa OprC is an outer membrane, TonB-dependent transporter that is conserved in many Proteobacteria and which mediates acquisition of both reduced and oxidised ionic copper via an unprecedented CxxxM-HxM metal binding site. Crystal structures of wild-type and mutant OprC variants with silver and copper suggest that acquisition of Cu(I) occurs via a surface-exposed “methionine track” leading towards the principal metal binding site. Together with whole-cell copper quantitation and quantitative proteomics in a murine lung infection model, our data identify OprC as an abundant component of bacterial copper biology that may enable copper acquisition under a wide range of conditions. How do Gram-negative bacteria acquire copper? This study shows that the outer membrane protein OprC from Pseudomonas aeruginosa is abundant during infection and mediates highly selective acquisition of both copper redox states via an extracellular "methionine track" and an unprecedented near-irreversible binding site.
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31
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Analysis of six tonB gene homologs in Bacteroides fragilis revealed that tonB3 is essential for survival in experimental intestinal colonization and intra-abdominal infection. Infect Immun 2021; 90:e0046921. [PMID: 34662212 DOI: 10.1128/iai.00469-21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The opportunistic, anaerobic pathogen and commensal of the human large intestinal tract, Bacteroides fragilis strain 638R, contains six predicted TonB proteins, termed TonB1-6, four ExbBs orthologs, ExbB1-4, and five ExbDs orthologs, ExbD1-5. The inner membrane TonB/ExbB/ExbD complex harvests energy from the proton motive force (Δp) and the TonB C-terminal domain interacts with and transduces energy to outer membrane TonB-dependent transporters (TBDTs). However, TonB's role in activating nearly one hundred TBDTs for nutrient acquisition in B. fragilis during intestinal colonization and extraintestinal infection has not been established. In this study, we show that growth was abolished in the ΔtonB3 mutant when heme, vitamin B12, Fe(III)-ferrichrome, starch, mucin-glycans, or N-linked glycans were used as a substrate for growth in vitro. Genetic complementation of the ΔtonB3 mutant with the tonB3 gene restored growth on these substrates. The ΔtonB1, ΔtonB2, ΔtonB4, ΔtonB5, and ΔtonB6 single mutants did not show a growth defect. This indicates that there was no functional compensation for the lack of TonB3, and it demonstrates that TonB3, alone, drives the TBDTs involved in the transport of essential nutrients. The ΔtonB3 mutant had a severe growth defect in a mouse model of intestinal colonization compared to the parent strain. This intestinal growth defect was enhanced in the ΔtonB3 ΔtonB6 double mutant strain which completely lost its ability to colonize the mouse intestinal tract compared to the parent strain. The ΔtonB1, ΔtonB2, ΔtonB4, and ΔtonB5 mutants did not significantly affect intestinal colonization. Moreover, the survival of the ΔtonB3 mutant strain was completely eradicated in a rat model of intra-abdominal infection. Taken together, these findings show that TonB3 was essential for survival in vivo. The genetic organization of tonB1, tonB2, tonB4, tonB5, and tonB6 gene orthologs indicates that they may interact with periplasmic and nonreceptor outer membrane proteins, but the physiological relevance of this has not been defined. Because anaerobic fermentation metabolism yields a lower Δp than aerobic respiration and B. fragilis has a reduced redox state in its periplasmic space - in contrast to an oxidative environment in aerobes - it remains to be determined if the diverse system of TonB/ExbB/ExbD orthologs encoded by B. fragilis have an increased sensitivity to PMF (relative to aerobic bacteria) to allow for the harvesting of energy under anaerobic conditions.
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Gumbart JC, Ferreira JL, Hwang H, Hazel AJ, Cooper CJ, Parks JM, Smith JC, Zgurskaya HI, Beeby M. Lpp positions peptidoglycan at the AcrA-TolC interface in the AcrAB-TolC multidrug efflux pump. Biophys J 2021; 120:3973-3982. [PMID: 34411576 DOI: 10.1016/j.bpj.2021.08.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 07/02/2021] [Accepted: 08/11/2021] [Indexed: 01/07/2023] Open
Abstract
The multidrug efflux pumps of Gram-negative bacteria are a class of complexes that span the periplasm, coupling both the inner and outer membranes to expel toxic molecules. The best-characterized example of these tripartite pumps is the AcrAB-TolC complex of Escherichia coli. However, how the complex interacts with the peptidoglycan (PG) cell wall, which is anchored to the outer membrane (OM) by Braun's lipoprotein (Lpp), is still largely unknown. In this work, we present molecular dynamics simulations of a complete, atomistic model of the AcrAB-TolC complex with the inner membrane, OM, and PG layers all present. We find that the PG localizes to the junction of AcrA and TolC, in agreement with recent cryo-tomography data. Free-energy calculations reveal that the positioning of PG is determined by the length and conformation of multiple Lpp copies anchoring it to the OM. The distance between the PG and OM measured in cryo-electron microscopy images of wild-type E. coli also agrees with the simulation-derived spacing. Sequence analysis of AcrA suggests a conserved role for interactions with PG in the assembly and stabilization of efflux pumps, one that may extend to other trans-envelope complexes as well.
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Affiliation(s)
- James C Gumbart
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia.
| | - Josie L Ferreira
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | - Hyea Hwang
- School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia
| | - Anthony J Hazel
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia
| | - Connor J Cooper
- UT/ORNL Center for Molecular Biophysics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Jerry M Parks
- UT/ORNL Center for Molecular Biophysics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - Jeremy C Smith
- UT/ORNL Center for Molecular Biophysics, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee; Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, Tennessee
| | - Helen I Zgurskaya
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, Oklahoma
| | - Morgan Beeby
- Department of Life Sciences, Imperial College London, London, United Kingdom
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Nilaweera TD, Nyenhuis DA, Cafiso DS. Structural intermediates observed only in intact Escherichia coli indicate a mechanism for TonB-dependent transport. eLife 2021; 10:68548. [PMID: 34251336 PMCID: PMC8341980 DOI: 10.7554/elife.68548] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Accepted: 07/11/2021] [Indexed: 12/17/2022] Open
Abstract
Outer membrane TonB-dependent transporters facilitate the uptake of trace nutrients and carbohydrates in Gram-negative bacteria and are essential for pathogenic bacteria and the health of the microbiome. Despite this, their mechanism of transport is still unknown. Here, pulse electron paramagnetic resonance (EPR) measurements were made in intact cells on the Escherichia coli vitamin B12 transporter, BtuB. Substrate binding was found to alter the C-terminal region of the core and shift an extracellular substrate binding loop 2 nm toward the periplasm; moreover, this structural transition is regulated by an ionic lock that is broken upon binding of the inner membrane protein TonB. Significantly, this structural transition is not observed when BtuB is reconstituted into phospholipid bilayers. These measurements suggest an alternative to existing models of transport, and they demonstrate the importance of studying outer membrane proteins in their native environment.
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Affiliation(s)
- Thushani D Nilaweera
- Department of Chemistry and Center for Membrane Biology, University of Virginia, Charlottesville, United States
| | - David A Nyenhuis
- Department of Chemistry and Center for Membrane Biology, University of Virginia, Charlottesville, United States
| | - David S Cafiso
- Department of Chemistry and Center for Membrane Biology, University of Virginia, Charlottesville, United States
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34
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Klebba PE, Newton SMC, Six DA, Kumar A, Yang T, Nairn BL, Munger C, Chakravorty S. Iron Acquisition Systems of Gram-negative Bacterial Pathogens Define TonB-Dependent Pathways to Novel Antibiotics. Chem Rev 2021; 121:5193-5239. [PMID: 33724814 PMCID: PMC8687107 DOI: 10.1021/acs.chemrev.0c01005] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Iron is an indispensable metabolic cofactor in both pro- and eukaryotes, which engenders a natural competition for the metal between bacterial pathogens and their human or animal hosts. Bacteria secrete siderophores that extract Fe3+ from tissues, fluids, cells, and proteins; the ligand gated porins of the Gram-negative bacterial outer membrane actively acquire the resulting ferric siderophores, as well as other iron-containing molecules like heme. Conversely, eukaryotic hosts combat bacterial iron scavenging by sequestering Fe3+ in binding proteins and ferritin. The variety of iron uptake systems in Gram-negative bacterial pathogens illustrates a range of chemical and biochemical mechanisms that facilitate microbial pathogenesis. This document attempts to summarize and understand these processes, to guide discovery of immunological or chemical interventions that may thwart infectious disease.
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Affiliation(s)
- Phillip E Klebba
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Salete M C Newton
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - David A Six
- Venatorx Pharmaceuticals, Inc., 30 Spring Mill Drive, Malvern, Pennsylvania 19355, United States
| | - Ashish Kumar
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Taihao Yang
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Brittany L Nairn
- Department of Biological Sciences, Bethel University, 3900 Bethel Drive, St. Paul, Minnesota 55112, United States
| | - Colton Munger
- Department of Biochemistry and Molecular Biophysics, Kansas State University, Manhattan, Kansas 66506, United States
| | - Somnath Chakravorty
- Jacobs School of Medicine and Biomedical Sciences, SUNY Buffalo, Buffalo, New York 14203, United States
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Jackson M, Stevens CM, Zhang L, Zgurskaya HI, Niederweis M. Transporters Involved in the Biogenesis and Functionalization of the Mycobacterial Cell Envelope. Chem Rev 2021; 121:5124-5157. [PMID: 33170669 PMCID: PMC8107195 DOI: 10.1021/acs.chemrev.0c00869] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The biology of mycobacteria is dominated by a complex cell envelope of unique composition and structure and of exceptionally low permeability. This cell envelope is the basis of many of the pathogenic features of mycobacteria and the site of susceptibility and resistance to many antibiotics and host defense mechanisms. This review is focused on the transporters that assemble and functionalize this complex structure. It highlights both the progress and the limits of our understanding of how (lipo)polysaccharides, (glyco)lipids, and other bacterial secretion products are translocated across the different layers of the cell envelope to their final extra-cytoplasmic location. It further describes some of the unique strategies evolved by mycobacteria to import nutrients and other products through this highly impermeable barrier.
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Affiliation(s)
- Mary Jackson
- Mycobacteria Research Laboratories, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523-1682, USA
| | - Casey M. Stevens
- University of Oklahoma, Department of Chemistry and Biochemistry, 101 Stephenson Parkway, Norman, OK 73019, USA
| | - Lei Zhang
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL 35294, USA
| | - Helen I. Zgurskaya
- University of Oklahoma, Department of Chemistry and Biochemistry, 101 Stephenson Parkway, Norman, OK 73019, USA
| | - Michael Niederweis
- Department of Microbiology, University of Alabama at Birmingham, 845 19th Street South, Birmingham, AL 35294, USA
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Dong Y, Li Q, Geng J, Cao Q, Zhao D, Jiang M, Li S, Lu C, Liu Y. The TonB system in Aeromonas hydrophila NJ-35 is essential for MacA 2B 2 efflux pump-mediated macrolide resistance. Vet Res 2021; 52:63. [PMID: 33926565 PMCID: PMC8082627 DOI: 10.1186/s13567-021-00934-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 03/19/2021] [Indexed: 12/19/2022] Open
Abstract
The TonB system is generally considered as an energy transporting device for the absorption of nutrients. Our recent study showed that deletion of this system caused a significantly increased sensitivity of Aeromonas hydrophila to the macrolides erythromycin and roxithromycin, but had no effect on other classes of antibiotics. In this study, we found the sensitivity of ΔtonB123 to all macrolides tested revealed a 8- to 16-fold increase compared with the wild-type (WT) strain, but this increase was not related with iron deprivation caused by tonB123 deletion. Further study demonstrated that the deletion of tonB123 did not damage the integrity of the bacterial membrane but did hinder the function of macrolide efflux. Compared with the WT strain, deletion of macA2B2, one of two ATP-binding cassette (ABC) types of the macrolide efflux pump, enhanced the sensitivity to the same levels as those of ΔtonB123. Interestingly, the deletion of macA2B2 in the ΔtonB123 mutant did not cause further increase in sensitivity to macrolide resistance, indicating that the macrolide resistance afforded by the MacA2B2 pump was completely abrogated by tonB123 deletion. In addition, macA2B2 expression was not altered in the ΔtonB123 mutant, indicating that any influence of TonB on MacA2B2-mediated macrolide resistance was at the pump activity level. In conclusion, inactivation of the TonB system significantly compromises the resistance of A. hydrophila to macrolides, and the mechanism of action is related to the function of MacA2B2-mediated macrolide efflux.
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Affiliation(s)
- Yuhao Dong
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Qing Li
- Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Jinzhu Geng
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Qing Cao
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Dan Zhao
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Mingguo Jiang
- Guangxi Key Laboratory for Polysaccharide Materials and Modifications, School of Marine Sciences and Biotechnology, Guangxi University for Nationalities, Nanning, China
| | - Shougang Li
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Chengping Lu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China
| | - Yongjie Liu
- Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu, China.
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Site-directed crosslinking identifies the stator-rotor interaction surfaces in a hybrid bacterial flagellar motor. J Bacteriol 2021; 203:JB.00016-21. [PMID: 33619152 PMCID: PMC8092157 DOI: 10.1128/jb.00016-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The bacterial flagellum is the motility organelle powered by a rotary motor. The rotor and stator elements of the motor are located in the cytoplasmic membrane and cytoplasm. The stator units assemble around the rotor, and an ion flux (typically H+ or Na+) conducted through a channel of the stator induces conformational changes that generate rotor torque. Electrostatic interactions between the stator protein PomA in Vibrio (MotA in Escherichia coli) and the rotor protein FliG have been shown by genetic analyses, but have not been demonstrated biochemically. Here, we used site-directed photo- and disulfide-crosslinking to provide direct evidence for the interaction. We introduced a UV-reactive amino acid, p-benzoyl-L-phenylalanine (pBPA), into the cytoplasmic region of PomA or the C-terminal region of FliG in intact cells. After UV irradiation, pBPA inserted at a number of positions in PomA formed a crosslink with FliG. PomA residue K89 gave the highest yield of crosslinks, suggesting that it is the PomA residue nearest to FliG. UV-induced crosslinking stopped motor rotation, and the isolated hook-basal body contained the crosslinked products. pBPA inserted to replace residues R281 or D288 in FliG formed crosslinks with the Escherichia coli stator protein, MotA. A cysteine residue introduced in place of PomA K89 formed disulfide crosslinks with cysteine inserted in place of FliG residues R281 and D288, and some other flanking positions. These results provide the first demonstration of direct physical interaction between specific residues in FliG and PomA/MotA.ImportanceThe bacterial flagellum is a unique organelle that functions as a rotary motor. The interaction between the stator and rotor is indispensable for stator assembly into the motor and the generation of motor torque. However, the interface of the stator-rotor interaction has only been defined by mutational analysis. Here, we detected the stator-rotor interaction using site-directed photo- and disulfide-crosslinking approaches. We identified several residues in the PomA stator, especially K89, that are in close proximity to the rotor. Moreover, we identified several pairs of stator and rotor residues that interact. This study directly demonstrates the nature of the stator-rotor interaction and suggests how stator units assemble around the rotor and generate torque in the bacterial flagellar motor.
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38
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Walker SS, Black TA. Are outer-membrane targets the solution for MDR Gram-negative bacteria? Drug Discov Today 2021; 26:2152-2158. [PMID: 33798647 DOI: 10.1016/j.drudis.2021.03.027] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 02/27/2021] [Accepted: 03/23/2021] [Indexed: 01/17/2023]
Abstract
The outer membrane (OM) of Gram-negative bacteria confers a significant barrier to many antibacterial agents targeting periplasmic and cytosolic functions. 'Synergist' approaches to disrupt the OM have been hampered by poor specificity and accompanying toxicities. The OM contains proteins required for optimal growth and pathogenesis, including lipopolysaccharide (LPS) and capsular polysaccharide (CPS) transport, porins for uptake of macromolecules, and transporters for essential elements (such as iron). Does the external proximity of these proteins offer an enhanced potential to identify effective therapies? Here, we review recent experiences in exploiting Gram-negative OM proteins (OMPs) to address the calamity of exploding antimicrobial resistance. Teaser: Multidrug-resistant (MDR) Gram-negative bacteria are a growing crisis. Few new antimicrobial chemotypes or targets have been identified after decades of screening. Are OMP targets a solution to MDR Gram-negative bacteria?
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Affiliation(s)
- Scott S Walker
- Infectious Diseases and Vaccines Basic Research, Merck & Co., Inc, 770 Sumneytown Pike, West Point, PA 19486, USA
| | - Todd A Black
- Infectious Diseases and Vaccines Basic Research, Merck & Co., Inc, 770 Sumneytown Pike, West Point, PA 19486, USA.
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Szczepaniak J, Press C, Kleanthous C. The multifarious roles of Tol-Pal in Gram-negative bacteria. FEMS Microbiol Rev 2021; 44:490-506. [PMID: 32472934 PMCID: PMC7391070 DOI: 10.1093/femsre/fuaa018] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 05/28/2020] [Indexed: 12/15/2022] Open
Abstract
In the 1960s several groups reported the isolation and preliminary genetic mapping of
Escherichia coli strains tolerant towards the
action of colicins. These pioneering studies kick-started two new fields in bacteriology;
one centred on how bacteriocins like colicins exploit the Tol (or more commonly Tol-Pal)
system to kill bacteria, the other on the physiological role of this cell
envelope-spanning assembly. The following half century has seen significant advances in
the first of these fields whereas the second has remained elusive, until recently. Here,
we review work that begins to shed light on Tol-Pal function in Gram-negative bacteria.
What emerges from these studies is that Tol-Pal is an energised system with fundamental,
interlinked roles in cell division – coordinating the re-structuring of peptidoglycan at
division sites and stabilising the connection between the outer membrane and underlying
cell wall. This latter role is achieved by Tol-Pal exploiting the proton motive force to
catalyse the accumulation of the outer membrane peptidoglycan associated lipoprotein Pal
at division sites while simultaneously mobilising Pal molecules from around the cell.
These studies begin to explain the diverse phenotypic outcomes of tol-pal
mutations, point to other cell envelope roles Tol-Pal may have and raise many new
questions.
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Affiliation(s)
- Joanna Szczepaniak
- Department of Biochemistry, South Parks Road, University of Oxford, Oxford OX1 3QU, UK
| | - Cara Press
- Department of Biochemistry, South Parks Road, University of Oxford, Oxford OX1 3QU, UK
| | - Colin Kleanthous
- Department of Biochemistry, South Parks Road, University of Oxford, Oxford OX1 3QU, UK
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40
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Pollet RM, Martin LM, Koropatkin NM. TonB-dependent transporters in the Bacteroidetes: Unique domain structures and potential functions. Mol Microbiol 2021; 115:490-501. [PMID: 33448497 DOI: 10.1111/mmi.14683] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 01/10/2021] [Accepted: 01/11/2021] [Indexed: 12/26/2022]
Abstract
The human gut microbiota endows the host with a wealth of metabolic functions central to health, one of which is the degradation and fermentation of complex carbohydrates. The Bacteroidetes are one of the dominant bacterial phyla of this community and possess an expanded capacity for glycan utilization. This is mediated via the coordinated expression of discrete polysaccharide utilization loci (PUL) that invariantly encode a TonB-dependent transporter (SusC) that works with a glycan-capturing lipoprotein (SusD). More broadly within Gram-negative bacteria, TonB-dependent transporters (TBDTs) are deployed for the uptake of not only sugars, but also more often for essential nutrients such as iron and vitamins. Here, we provide a comprehensive look at the repertoire of TBDTs found in the model gut symbiont Bacteroides thetaiotaomicron and the range of predicted functional domains associated with these transporters and SusD proteins for the uptake of both glycans and other nutrients. This atlas of the B. thetaiotaomicron TBDTs reveals that there are at least three distinct subtypes of these transporters encoded within its genome that are presumably regulated in different ways to tune nutrient uptake.
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Affiliation(s)
| | - Lauryn M Martin
- Department of Biology, Alcorn State University, Alcorn, MS, USA
| | - Nicole M Koropatkin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
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41
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Lunar Silva I, Cascales E. Molecular Strategies Underlying Porphyromonas gingivalis Virulence. J Mol Biol 2021; 433:166836. [PMID: 33539891 DOI: 10.1016/j.jmb.2021.166836] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 01/15/2021] [Accepted: 01/15/2021] [Indexed: 02/07/2023]
Abstract
The anaerobic Gram-negative bacterium Porphyromonas gingivalis is considered the keystone of periodontitis diseases, a set of inflammatory conditions that affects the tissues surrounding the teeth. In the recent years, the major virulence factors exploited by P. gingivalis have been identified and characterized, including a cocktail of toxins, mainly proteases called gingipains, which promote gingival tissue invasion. These effectors use the Sec pathway to cross the inner membrane and are then recruited and transported across the outer membrane by the type IX secretion system (T9SS). In P. gingivalis, most secreted effectors are attached to anionic lipopolysaccharides (A-LPS), and hence form a virulence coat at the cell surface. P. gingivalis produces additional virulence factors to evade host immune responses, such as capsular polysaccharide, fimbriae and outer membrane vesicles. In addition to periodontitis, it is proposed that this broad repertoire of virulence factors enable P. gingivalis to be involved in diverse human diseases such as rheumatoid arthritis, and neurodegenerative, Alzheimer, and cardiovascular disorders. Here, we review the major virulence determinants of P. gingivalis and discuss future directions to better understand their mechanisms of action.
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Affiliation(s)
- Ignacio Lunar Silva
- Laboratoire d'Ingénierie des Syst èmes Macromol éculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), UMR7255, 31 Chemin Joseph Aiguier CS7071, 13009 Marseille Cedex 20, France.
| | - Eric Cascales
- Laboratoire d'Ingénierie des Syst èmes Macromol éculaires (LISM), Institut de Microbiologie, Bioénergies and Biotechnologie (IM2B), Aix-Marseille Université, Centre National de la Recherche Scientifique (CNRS), UMR7255, 31 Chemin Joseph Aiguier CS7071, 13009 Marseille Cedex 20, France.
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Virtanen SI, Kiirikki AM, Mikula KM, Iwaï H, Ollila OHS. Heterogeneous dynamics in partially disordered proteins. Phys Chem Chem Phys 2021; 22:21185-21196. [PMID: 32929427 DOI: 10.1039/d0cp03473h] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Importance of disordered protein regions is increasingly recognized in biology, but their characterization remains challenging due to the lack of suitable experimental and theoretical methods. NMR experiments can detect multiple timescale dynamics and structural details of disordered protein regions, but their detailed interpretation is often difficult. Here we combine protein backbone 15N spin relaxation data with molecular dynamics (MD) simulations to detect not only heterogeneous dynamics of large partially disordered proteins but also their conformational ensembles. We observed that the rotational dynamics of folded regions in partially disordered proteins is dominated by similar rigid body rotation as in globular proteins, thereby being largely independent of flexible disordered linkers. Disordered regions, on the other hand, exhibit complex rotational motions with multiple timescales below ∼30 ns which are difficult to detect from experimental data alone, but can be captured by MD simulations. Combining MD simulations and backbone 15N spin relaxation data, measured applying segmental isotopic labeling with salt-inducible split intein, we resolved the conformational ensemble and dynamics of partially disordered periplasmic domain of TonB protein from Helicobacter pylori containing 250 residues. To demonstrate the universality of our approach, it was applied also to the partially disordered region of chicken Engrailed 2. Our results pave the way in understanding how TonB transfers energy from inner membrane to the outer membrane receptors in Gram-negative bacteria, as well as the function of other proteins with disordered domains.
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Affiliation(s)
- Salla I Virtanen
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
| | - Anne M Kiirikki
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
| | - Kornelia M Mikula
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
| | - Hideo Iwaï
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
| | - O H Samuli Ollila
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
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43
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Nishikino T, Kojima S, Homma M. [Flagellar related genes and functions in Vibrio]. Nihon Saikingaku Zasshi 2021; 75:195-214. [PMID: 33390367 DOI: 10.3412/jsb.75.195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Bacteria can move or swim by flagella. On the other hand, the motile ability is not necessary to live at all. In laboratory, the flagella-deficient strains can grow just like the wild-type strains. The flagellum is assembled from more than 20 structural proteins and there are more than 50 genes including the structural genes to regulate or support the flagellar formation. The cost to construct the flagellum is so expensive. The fact that it evolved as a motor organ means even at such the large cost shows that the flagellum is essential for survival in natural condition. In this review, we would like to focus on the flagella-related researches conducted by the authors and the flagellar research on Vibrio spp.
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Affiliation(s)
| | - Seiji Kojima
- Division of Biological Science, Graduate School of Science, Nagoya University
| | - Michio Homma
- Division of Biological Science, Graduate School of Science, Nagoya University
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44
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Kotov V, Mlynek G, Vesper O, Pletzer M, Wald J, Teixeira‐Duarte CM, Celia H, Garcia‐Alai M, Nussberger S, Buchanan SK, Morais‐Cabral JH, Loew C, Djinovic‐Carugo K, Marlovits TC. In-depth interrogation of protein thermal unfolding data with MoltenProt. Protein Sci 2021; 30:201-217. [PMID: 33140490 PMCID: PMC7737771 DOI: 10.1002/pro.3986] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/27/2020] [Accepted: 10/30/2020] [Indexed: 01/06/2023]
Abstract
Protein stability is a key factor in successful structural and biochemical research. However, the approaches for systematic comparison of protein stability are limited by sample consumption or compatibility with sample buffer components. Here we describe how miniaturized measurement of intrinsic tryptophan fluorescence (NanoDSF assay) in combination with a simplified description of protein unfolding can be used to interrogate the stability of a protein sample. We demonstrate that improved protein stability measures, such as apparent Gibbs free energy of unfolding, rather than melting temperature Tm , should be used to rank the results of thermostability screens. The assay is compatible with protein samples of any composition, including protein complexes and membrane proteins. Our data analysis software, MoltenProt, provides an easy and robust way to perform characterization of multiple samples. Potential applications of MoltenProt and NanoDSF include buffer and construct optimization for X-ray crystallography and cryo-electron microscopy, screening for small-molecule binding partners and comparison of effects of point mutations.
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Affiliation(s)
- Vadim Kotov
- Centre for Structural Systems Biology (CSSB)HamburgGermany
- Institute for Structural and Systems BiologyUniversity Medical Center Hamburg‐Eppendorf (UKE)HamburgGermany
- German Electron Synchrotron Centre (DESY)HamburgGermany
| | - Georg Mlynek
- Department of Structural and Computational Biology, Max Perutz Labs ViennaUniversity of ViennaViennaAustria
| | - Oliver Vesper
- Centre for Structural Systems Biology (CSSB)HamburgGermany
- Institute for Structural and Systems BiologyUniversity Medical Center Hamburg‐Eppendorf (UKE)HamburgGermany
- German Electron Synchrotron Centre (DESY)HamburgGermany
| | - Marina Pletzer
- Department of Structural and Computational Biology, Max Perutz Labs ViennaUniversity of ViennaViennaAustria
| | - Jiri Wald
- Centre for Structural Systems Biology (CSSB)HamburgGermany
- Institute for Structural and Systems BiologyUniversity Medical Center Hamburg‐Eppendorf (UKE)HamburgGermany
- German Electron Synchrotron Centre (DESY)HamburgGermany
| | - Celso M. Teixeira‐Duarte
- Instituto de Investigação e Inovação em Saúde (i3S) and Instituto de Biologia Molecular e Celular (IBMC)Universidade do PortoPortoPortugal
| | - Herve Celia
- Laboratory of Molecular Biology, National Institute of Diabetes & Digestive & Kidney DiseasesNational Institutes of HealthBethesdaMarylandUSA
| | - Maria Garcia‐Alai
- Centre for Structural Systems Biology (CSSB)HamburgGermany
- European Molecular Biology Laboratory (EMBL)Hamburg UnitHamburgGermany
| | - Stephan Nussberger
- Department of Biophysics, Institute of Biomaterials and Biomolecular SystemsUniversity of StuttgartStuttgartGermany
| | - Susan K. Buchanan
- Laboratory of Molecular Biology, National Institute of Diabetes & Digestive & Kidney DiseasesNational Institutes of HealthBethesdaMarylandUSA
| | - João H. Morais‐Cabral
- Instituto de Investigação e Inovação em Saúde (i3S) and Instituto de Biologia Molecular e Celular (IBMC)Universidade do PortoPortoPortugal
| | - Christian Loew
- Centre for Structural Systems Biology (CSSB)HamburgGermany
- European Molecular Biology Laboratory (EMBL)Hamburg UnitHamburgGermany
| | - Kristina Djinovic‐Carugo
- Department of Structural and Computational Biology, Max Perutz Labs ViennaUniversity of ViennaViennaAustria
- Department of Biochemistry, Faculty of Chemistry and Chemical TechnologyUniversity of LjubljanaLjubljanaSlovenia
| | - Thomas C. Marlovits
- Centre for Structural Systems Biology (CSSB)HamburgGermany
- Institute for Structural and Systems BiologyUniversity Medical Center Hamburg‐Eppendorf (UKE)HamburgGermany
- German Electron Synchrotron Centre (DESY)HamburgGermany
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45
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Chorev DS, Robinson CV. The importance of the membrane for biophysical measurements. Nat Chem Biol 2020; 16:1285-1292. [PMID: 33199903 PMCID: PMC7116504 DOI: 10.1038/s41589-020-0574-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 05/22/2020] [Indexed: 11/09/2022]
Abstract
Within cell membranes numerous protein assemblies reside. Among their many functions, these assemblies regulate the movement of molecules between membranes, facilitate signaling into and out of cells, allow movement of cells by cell-matrix attachment, and regulate the electric potential of the membrane. With such critical roles, membrane protein complexes are of considerable interest for human health, yet they pose an enduring challenge for structural biologists because it is difficult to study these protein structures at atomic resolution in in situ environments. To advance structural and functional insights for these protein assemblies, membrane mimetics are typically employed to recapitulate some of the physical and chemical properties of the lipid bilayer membrane. However, extraction from native membranes can sometimes change the structure and lipid-binding properties of these complexes, leading to conflicting results and fueling a drive to study complexes directly from native membranes. Here we consider the co-development of membrane mimetics with technological breakthroughs in both cryo-electron microscopy (cryo-EM) and native mass spectrometry (nMS). Together, these developments are leading to a plethora of high-resolution protein structures, as well as new knowledge of their lipid interactions, from different membrane-like environments.
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Affiliation(s)
- Dror S Chorev
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, UK
| | - Carol V Robinson
- Physical and Theoretical Chemistry Laboratory, University of Oxford, Oxford, UK.
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46
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Deme JC, Johnson S, Vickery O, Aron A, Monkhouse H, Griffiths T, James RH, Berks BC, Coulton JW, Stansfeld PJ, Lea SM. Structures of the stator complex that drives rotation of the bacterial flagellum. Nat Microbiol 2020; 5:1553-1564. [PMID: 32929189 PMCID: PMC7610383 DOI: 10.1038/s41564-020-0788-8] [Citation(s) in RCA: 103] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 08/11/2020] [Indexed: 01/17/2023]
Abstract
The bacterial flagellum is the prototypical protein nanomachine and comprises a rotating helical propeller attached to a membrane-embedded motor complex. The motor consists of a central rotor surrounded by stator units that couple ion flow across the cytoplasmic membrane to generate torque. Here, we present the structures of the stator complexes from Clostridium sporogenes, Bacillus subtilis and Vibrio mimicus, allowing interpretation of the extensive body of data on stator mechanism. The structures reveal an unexpected asymmetric A5B2 subunit assembly where the five A subunits enclose the two B subunits. Comparison to structures of other ion-driven motors indicates that this A5B2 architecture is fundamental to bacterial systems that couple energy from ion flow to generate mechanical work at a distance and suggests that such events involve rotation in the motor structures.
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Affiliation(s)
- Justin C Deme
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
- Central Oxford Structural Molecular Imaging Centre, University of Oxford, Oxford, UK
| | - Steven Johnson
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Owen Vickery
- Department of Biochemistry, University of Oxford, Oxford, UK
- School of Life Sciences & Department of Chemistry, University of Warwick, Coventry, UK
| | - Amy Aron
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Holly Monkhouse
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | - Thomas Griffiths
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
| | | | - Ben C Berks
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - James W Coulton
- Department of Microbiology and Immunology, McGill University, Montreal, Quebec, Canada
- Département de Biochemie et Médecine Moleculaire, Université de Montréal, Montréal, Quebec, Canada
| | - Phillip J Stansfeld
- Department of Biochemistry, University of Oxford, Oxford, UK
- School of Life Sciences & Department of Chemistry, University of Warwick, Coventry, UK
| | - Susan M Lea
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
- Central Oxford Structural Molecular Imaging Centre, University of Oxford, Oxford, UK.
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47
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Chen X, Wu X, Gao J, Ying H, Dong X, Che J, Shen Z. Identification of new IDH2 R140Q inhibitors by discriminatory analysis-based molecular docking and biological evaluation. Arch Pharm (Weinheim) 2020; 354:e2000063. [PMID: 33184958 DOI: 10.1002/ardp.202000063] [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: 03/02/2020] [Revised: 09/29/2020] [Accepted: 10/24/2020] [Indexed: 11/07/2022]
Abstract
Isocitrate dehydrogenase 2 (IDH2) is a key enzyme in the regulation of cell metabolism. Its mutated type can lead to the accumulation of 2-hydroxyglutarate, which is often related to malignancies such as acute myeloid leukemia. Therefore, it is necessary to find new inhibitors targeting mutant IDH2. Discriminatory analysis-based molecular docking was employed to screen the ChemDiv compound library, which resulted in the identification of three new IDH2R140Q inhibitors with moderate-to-good IC50 values. Among them, compounds 1 and 3 displayed good selectivity against other mutant or wild-type IDH proteins. The most potent compound 1, bearing the [1,2,4]triazolo[1,5-a]pyrimidin scaffold, was subjected to dynamic simulations to provide more information on the binding mode with IDH2R140Q , providing structural clues to further optimize compound 1 as a new mutant IDH2 inhibitor.
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Affiliation(s)
- Xiaoyun Chen
- Department of Otolaryngology, Head and Neck Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Xianmin Wu
- Department of Otolaryngology, Head and Neck Surgery, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Jian Gao
- Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Huazhou Ying
- Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Xiaowu Dong
- Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Jinxin Che
- Hangzhou Institute of Innovative Medicine, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, China
| | - Zhijian Shen
- Department of Hematology, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
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48
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Alvira S, Watkins DW, Troman LA, Allen WJ, Lorriman JS, Degliesposti G, Cohen EJ, Beeby M, Daum B, Gold VAM, Skehel JM, Collinson I. Inter-membrane association of the Sec and BAM translocons for bacterial outer-membrane biogenesis. eLife 2020; 9:e60669. [PMID: 33146611 PMCID: PMC7695460 DOI: 10.7554/elife.60669] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 11/03/2020] [Indexed: 12/24/2022] Open
Abstract
The outer-membrane of Gram-negative bacteria is critical for surface adhesion, pathogenicity, antibiotic resistance and survival. The major constituent - hydrophobic β-barrel Outer-Membrane Proteins (OMPs) - are first secreted across the inner-membrane through the Sec-translocon for delivery to periplasmic chaperones, for example SurA, which prevent aggregation. OMPs are then offloaded to the β-Barrel Assembly Machinery (BAM) in the outer-membrane for insertion and folding. We show the Holo-TransLocon (HTL) - an assembly of the protein-channel core-complex SecYEG, the ancillary sub-complex SecDF, and the membrane 'insertase' YidC - contacts BAM through periplasmic domains of SecDF and YidC, ensuring efficient OMP maturation. Furthermore, the proton-motive force (PMF) across the inner-membrane acts at distinct stages of protein secretion: (1) SecA-driven translocation through SecYEG and (2) communication of conformational changes via SecDF across the periplasm to BAM. The latter presumably drives efficient passage of OMPs. These interactions provide insights of inter-membrane organisation and communication, the importance of which is becoming increasingly apparent.
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Affiliation(s)
- Sara Alvira
- School of Biochemistry, University of BristolBristolUnited Kingdom
| | - Daniel W Watkins
- School of Biochemistry, University of BristolBristolUnited Kingdom
| | - Luca A Troman
- School of Biochemistry, University of BristolBristolUnited Kingdom
| | - William J Allen
- School of Biochemistry, University of BristolBristolUnited Kingdom
| | - James S Lorriman
- School of Biochemistry, University of BristolBristolUnited Kingdom
| | - Gianluca Degliesposti
- Biological Mass Spectrometry and Proteomics, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Eli J Cohen
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
| | - Morgan Beeby
- Department of Life Sciences, Imperial College LondonLondonUnited Kingdom
| | - Bertram Daum
- Living Systems Institute, University of ExeterExeterUnited Kingdom
- College of Life and Environmental Sciences, University of ExeterExeterUnited Kingdom
| | - Vicki AM Gold
- Living Systems Institute, University of ExeterExeterUnited Kingdom
- College of Life and Environmental Sciences, University of ExeterExeterUnited Kingdom
| | - J Mark Skehel
- Biological Mass Spectrometry and Proteomics, MRC Laboratory of Molecular BiologyCambridgeUnited Kingdom
| | - Ian Collinson
- School of Biochemistry, University of BristolBristolUnited Kingdom
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49
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Ratliff AC, Buchanan SK, Celia H. Ton motor complexes. Curr Opin Struct Biol 2020; 67:95-100. [PMID: 33157479 DOI: 10.1016/j.sbi.2020.09.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Revised: 09/21/2020] [Accepted: 09/28/2020] [Indexed: 12/15/2022]
Abstract
The Ton complex is a molecular motor that uses the proton gradient at the inner membrane of Gram-negative bacteria to apply forces on outer membrane proteins, allowing active transport of nutrients into the periplasmic space. For decades, contradictory data has been reported on the structure and stoichiometry of the Ton complex. However, recent reports strongly support a subunit stoichiometry of 5:2 for the ExbB-ExbD subcomplex. In this review, we summarize the recent discoveries of the structures and proposed mechanisms of the Ton system, as well as similar protein motor complexes in Gram-negative bacteria.
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Affiliation(s)
- Anna C Ratliff
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Susan K Buchanan
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Herve Celia
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
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50
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FusB Energizes Import across the Outer Membrane through Direct Interaction with Its Ferredoxin Substrate. mBio 2020; 11:mBio.02081-20. [PMID: 33109756 PMCID: PMC7593965 DOI: 10.1128/mbio.02081-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Phytopathogenic Pectobacterium spp. import ferredoxin into the periplasm for proteolytic processing and iron release via the ferredoxin uptake system. Although the ferredoxin receptor FusA and the processing protease FusC have been identified, the mechanistic basis of ferredoxin import is poorly understood. In this work, we demonstrate that protein translocation across the outer membrane is dependent on the TonB-like protein FusB. In contrast to the loss of FusC, loss of FusB or FusA abolishes ferredoxin transport to the periplasm, demonstrating that FusA and FusB work in concert to transport ferredoxin across the outer membrane. In addition to an interaction with the "TonB box" region of FusA, FusB also forms a complex with the ferredoxin substrate, with complex formation required for substrate transport. These data suggest that ferredoxin transport requires energy transduction from the cytoplasmic membrane via FusB both for removal of the FusA plug domain and for substrate translocation through the FusA barrel.IMPORTANCE The ability to acquire iron is key to the ability of bacteria to cause infection. Plant-pathogenic Pectobacterium spp. are able to acquire iron from plants by transporting the iron-containing protein ferredoxin into the cell from proteolytic processing. In this work, we show that the TonB-like protein FusB plays a key role in transporting ferredoxin across the bacterial outer membrane by directly energizing its transport into the cell. The direct interaction of the TonB-like protein with substrate is unprecedented and explains the requirement for the system-specific TonB homologue in the ferredoxin uptake system. Since multiple genes encoding TonB-like proteins are commonly found in the genomes of Gram-negative bacteria, this may be a common mechanism for the uptake of atypical substrates via TonB-dependent receptors.
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