1
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Alcorlo M, Martínez-Caballero S, Li J, Sham LT, Luo M, Hermoso JA. Modulation of the lytic apparatus by the FtsEX complex within the bacterial division machinery. FEBS Lett 2024. [PMID: 38849310 DOI: 10.1002/1873-3468.14953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2024] [Revised: 05/24/2024] [Accepted: 05/28/2024] [Indexed: 06/09/2024]
Abstract
The FtsEX membrane complex constitutes an essential component of the ABC transporter superfamily, widely distributed among bacterial species. It governs peptidoglycan degradation for cell division, acting as a signal transmitter rather than a substrate transporter. Through the ATPase activity of FtsE, it facilitates signal transmission from the cytosol across the membrane to the periplasm, activating associated peptidoglycan hydrolases. This review concentrates on the latest structural advancements elucidating the architecture of the FtsEX complex and its interplay with lytic enzymes or regulatory counterparts. The revealed three-dimensional structures unveil a landscape wherein a precise array of intermolecular interactions, preserved across diverse bacterial species, afford meticulous spatial and temporal control over the cell division process.
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Affiliation(s)
- Martín Alcorlo
- Department of Crystallography and Structural Biology, Instituto de Química-Física "Blas Cabrera", Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Siseth Martínez-Caballero
- Department of Crystallography and Structural Biology, Instituto de Química-Física "Blas Cabrera", Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Jianwei Li
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore
- Department of Biological Sciences, Center for Bioimaging Sciences, National University of Singapore, Singapore
| | - Lok-To Sham
- Infectious Diseases Translational Research Programme and Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Min Luo
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore
- Department of Biological Sciences, Center for Bioimaging Sciences, National University of Singapore, Singapore
| | - Juan A Hermoso
- Department of Crystallography and Structural Biology, Instituto de Química-Física "Blas Cabrera", Consejo Superior de Investigaciones Científicas, Madrid, Spain
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2
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Wang XY, Yan J, Xie J. Coculture of Acinetobacter johnsonii and Shewanella putrefaciens Contributes to the ABC Transporter that Impacts Cold Adaption in the Aquatic Food Storage Environment. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:10605-10615. [PMID: 38647030 DOI: 10.1021/acs.jafc.4c00885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Acinetobacter johnsonii and Shewanella putrefaciens were identified as specific spoilage organisms in aquatic food. The interactions among specific spoilage organisms under cold stress have a significant impact on the assembly of microbial communities, which play crucial roles in the spoilage and cold adaptation processes. The limited understanding of A. johnsonii and S. putrefaciens interactions in the cold adaptation mechanism hinders the elucidation of their roles in protein and metabolism levels. 4D quantitative proteomic analysis showed that the coculture of A. johnsonii and S. putrefaciens responds to low temperatures through ABC transporter proteins, resulting in phospholipid transport and inner membrane components. SapA and FtsX proteins were significantly upregulated, while LolC, LolD, LolE, PotD, PotA, PotB, and PotC proteins were significantly downregulated. Metabolome assays revealed that metabolites of glutathione and spermidine/putrescin were significantly upregulated, while metabolites of arginine/lysine/ornithine were significantly downregulated and involved in the ABC transporter metabolism. The results of ultramicroscopic analyses showed that the coculture of A. johnsonii and S. putrefaciens surface combined with the presence of the leakage of intracellular contents, suggesting that the bacteria were severely damaged and wrinkled to absorb metabolic nutrients and adapt to cold temperatures.
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Affiliation(s)
- Xin-Yun Wang
- International Peace Maternity & Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, Shanghai 200300, China
- College of Food Science & Technology, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Engineering Research Center of Aquatic Product Processing & Preservation, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation, Shanghai Ocean University, Shanghai 201306, China
| | - Jun Yan
- College of Food Science & Technology, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Engineering Research Center of Aquatic Product Processing & Preservation, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation, Shanghai Ocean University, Shanghai 201306, China
- National Experimental Teaching Demonstration Center for Food Science and Engineering Shanghai Ocean University, Shanghai 201306, China
| | - Jing Xie
- College of Food Science & Technology, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Engineering Research Center of Aquatic Product Processing & Preservation, Shanghai Ocean University, Shanghai 201306, China
- Shanghai Professional Technology Service Platform on Cold Chain Equipment Performance and Energy Saving Evaluation, Shanghai Ocean University, Shanghai 201306, China
- National Experimental Teaching Demonstration Center for Food Science and Engineering Shanghai Ocean University, Shanghai 201306, China
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3
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Tao K, Narita SI, Okada U, Murakami S, Tokuda H. Dissection of an ABC transporter LolCDE function analyzed by photo-crosslinking. J Biochem 2024; 175:427-437. [PMID: 38156779 PMCID: PMC11005994 DOI: 10.1093/jb/mvad118] [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: 09/07/2023] [Accepted: 12/15/2023] [Indexed: 01/03/2024] Open
Abstract
The envelope of Escherichia coli contains approximately 100 different species of lipoproteins, most of which are localized to the inner leaflet of the outer membrane. The localization of lipoprotein (Lol) system, consisting of five Lol proteins, is responsible for the trafficking of lipoproteins to the outer membrane. LolCDE binds to lipoproteins destined for the outer membrane and transfers them to the periplasmic chaperone LolA. Although the cryo-EM structures of E. coli LolCDE have been reported, the mechanisms by which outer membrane lipoproteins are transferred to LolA remain elusive. In this study, we investigated the interaction between LolCDE and lipoproteins using site-specific photo-crosslinking. We introduced a photo-crosslinkable amino acid into different locations across the four helices which form the central lipoprotein-binding cavity, and identified domains that crosslink with peptidoglycan-associated lipoprotein (Pal) in vivo. Using one of the derivatives containing the photo-crosslinkable amino acid, we developed an in vitro system to analyze the binding of lipoproteins to LolCDE. Our results indicate that compound 2, a LolCDE inhibitor, does not inhibit the binding of lipoproteins to LolCDE, but rather promotes the dissociation of bound lipoproteins from LolCDE.
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Affiliation(s)
- Kazuyuki Tao
- Isotope Science Center, University of Tokyo, 2-11-16 Yayoi, Bunky-ku, Tokyo 113-0032, Japan
| | - Shin-ichiro Narita
- Faculty of Health and Nutrition, Yamagata Prefectural Yonezawa University of Nutrition Sciences, Yonezawa, Yamagata 992-0025, Japan
| | - Ui Okada
- Department of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
| | - Satoshi Murakami
- Department of Life Science and Technology, Tokyo Institute of Technology, Nagatsuta, Midori-ku, Yokohama 226-8501, Japan
| | - Hajime Tokuda
- Faculty of Nutritional Sciences, University of Morioka, Takizawa, Iwate 020-0694, Japan
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4
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Sharifian Gh. M, Norouzi F, Sorci M, Zaid TS, Pier GB, Achimovich A, Ongwae GM, Liang B, Ryan M, Lemke M, Belfort G, Gadjeva M, Gahlmann A, Pires MM, Venter H, Harris TE, Laurie GW. Targeting Iron - Respiratory Reciprocity Promotes Bacterial Death. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.01.582947. [PMID: 38464199 PMCID: PMC10925246 DOI: 10.1101/2024.03.01.582947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
Discovering new bacterial signaling pathways offers unique antibiotic strategies. Here, through an unbiased resistance screen of 3,884 gene knockout strains, we uncovered a previously unknown non-lytic bactericidal mechanism that sequentially couples three transporters and downstream transcription to lethally suppress respiration of the highly virulent P. aeruginosa strain PA14 - one of three species on the WHO's 'Priority 1: Critical' list. By targeting outer membrane YaiW, cationic lacritin peptide 'N-104' translocates into the periplasm where it ligates outer loops 4 and 2 of the inner membrane transporters FeoB and PotH, respectively, to suppress both ferrous iron and polyamine uptake. This broadly shuts down transcription of many biofilm-associated genes, including ferrous iron-dependent TauD and ExbB1. The mechanism is innate to the surface of the eye and is enhanced by synergistic coupling with thrombin peptide GKY20. This is the first example of an inhibitor of multiple bacterial transporters.
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Affiliation(s)
| | - Fatemeh Norouzi
- Department of Cell Biology, University of Virginia, Charlottesville VA, USA
| | - Mirco Sorci
- Howard P. Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy NY, USA
| | - Tanweer S Zaid
- Division of Infectious Disease, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston MA
| | - Gerald B. Pier
- Division of Infectious Disease, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston MA
| | - Alecia Achimovich
- Department of Chemistry, University of Virginia, Charlottesville VA, USA
| | - George M. Ongwae
- Department of Chemistry, University of Virginia, Charlottesville VA, USA
| | - Binyong Liang
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville VA, USA
| | - Margaret Ryan
- Department of Cell Biology, University of Virginia, Charlottesville VA, USA
| | - Michael Lemke
- Department of Pharmacology, University of Virginia, Charlottesville VA, USA
| | - Georges Belfort
- Howard P. Isermann Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy NY, USA
| | - Mihaela Gadjeva
- Division of Infectious Disease, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston MA
| | - Andreas Gahlmann
- Department of Chemistry, University of Virginia, Charlottesville VA, USA
| | - Marcos M. Pires
- Department of Chemistry, University of Virginia, Charlottesville VA, USA
| | - Henrietta Venter
- Sansom Institute for Health Research, University of South Australia, Adelaide, Australia
| | - Thurl E. Harris
- Department of Pharmacology, University of Virginia, Charlottesville VA, USA
| | - Gordon W. Laurie
- Department of Cell Biology, University of Virginia, Charlottesville VA, USA
- Department of Ophthalmology, University of Virginia, Charlottesville VA, USA
- Department of Biomedical Engineering, University of Virginia, Charlottesville VA, USA
- Contact author: Gordon Laurie
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5
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Lehman KM, May KL, Marotta J, Grabowicz M. Genetic analysis reveals a robust and hierarchical recruitment of the LolA chaperone to the LolCDE lipoprotein transporter. mBio 2024; 15:e0303923. [PMID: 38193657 PMCID: PMC10865981 DOI: 10.1128/mbio.03039-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 11/29/2023] [Indexed: 01/10/2024] Open
Abstract
The outer membrane (OM) is an essential organelle of Gram-negative bacteria. Lipoproteins are key to building the OM, performing essential functions in several OM assembly machines. Lipoproteins mature in the inner membrane (IM) and are then trafficked to the OM. In Escherichia coli, the LolCDE transporter is needed to extract lipoproteins from the IM to begin trafficking. Lipoproteins are then transferred from LolCDE to the periplasmic chaperone LolA which ferries them to the OM for insertion by LolB. LolA recruitment by LolC is an essential trafficking step. Structural and biochemical studies suggested that two regions (termed Hook and Pad) within a periplasmic loop of LolC worked in tandem to recruit LolA, leading to a bipartite model for recruitment. Here, we genetically examine the LolC periplasmic loop in vivo using E. coli. Our findings challenge the bipartite interaction model. We show that while the Hook is essential for lipoprotein trafficking in vivo, lipoproteins are still efficiently trafficked when the Pad residues are inactivated. We show with AlphaFold2 multimer modeling that Hook:LolA interactions are likely universal among diverse Gram-negative bacteria. Conversely, Pad:LolA interactions vary across phyla. Our in vivo data redefine LolC:LolA recruitment into a hierarchical interaction model. We propose that the Hook is the major player in LolA recruitment, while the Pad plays an ancillary role that is important for efficiency but is ultimately dispensable. Our findings expand the understanding of a fundamental step in essential lipoprotein trafficking and have implications for efforts to develop new antibacterials that target LolCDE.IMPORTANCEResistance to current antibiotics is increasingly common. New antibiotics that target essential processes are needed to expand clinical options. For Gram-negative bacteria, their cell surface-the outer membrane (OM)-is an essential organelle and antibiotic barrier that is an attractive target for new antibacterials. Lipoproteins are key to building the OM. The LolCDE transporter is needed to supply the OM with lipoproteins and has been a focus of recent antibiotic discovery. In vitro evidence recently proposed a two-part interaction of LolC with LolA lipoprotein chaperone (which traffics lipoproteins to the OM) via "Hook" and "Pad" regions. We show that this model does not reflect lipoprotein trafficking in vivo. Only the Hook is essential for lipoprotein trafficking and is remarkably robust to mutational changes. The Pad is non-essential for lipoprotein trafficking but plays an ancillary role, contributing to trafficking efficiency. These insights inform ongoing efforts to drug LolCDE.
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Affiliation(s)
- Kelly M. Lehman
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
- Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Kerrie L. May
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
- Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Julianna Marotta
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
- Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Marcin Grabowicz
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
- Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
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6
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Gómez Borrego J, Torrent Burgas M. Structural assembly of the bacterial essential interactome. eLife 2024; 13:e94919. [PMID: 38226900 PMCID: PMC10863985 DOI: 10.7554/elife.94919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 12/22/2023] [Indexed: 01/17/2024] Open
Abstract
The study of protein interactions in living organisms is fundamental for understanding biological processes and central metabolic pathways. Yet, our knowledge of the bacterial interactome remains limited. Here, we combined gene deletion mutant analysis with deep-learning protein folding using AlphaFold2 to predict the core bacterial essential interactome. We predicted and modeled 1402 interactions between essential proteins in bacteria and generated 146 high-accuracy models. Our analysis reveals previously unknown details about the assembly mechanisms of these complexes, highlighting the importance of specific structural features in their stability and function. Our work provides a framework for predicting the essential interactomes of bacteria and highlight the potential of deep-learning algorithms in advancing our understanding of the complex biology of living organisms. Also, the results presented here offer a promising approach to identify novel antibiotic targets.
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Affiliation(s)
- Jordi Gómez Borrego
- Systems Biology of Infection Lab, Department of Biochemistry and Molecular Biology, Biosciences Faculty, Universitat Autònoma de BarcelonaCerdanyola del VallèsSpain
| | - Marc Torrent Burgas
- Systems Biology of Infection Lab, Department of Biochemistry and Molecular Biology, Biosciences Faculty, Universitat Autònoma de BarcelonaCerdanyola del VallèsSpain
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7
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Breidenstein EBM, Khan N, Duffy T, Coward C, Avis T, Abdulle O, Li CM, Mason CS. SMT-738: a novel small-molecule inhibitor of bacterial lipoprotein transport targeting Enterobacteriaceae. Antimicrob Agents Chemother 2024; 68:e0069523. [PMID: 38084954 PMCID: PMC10777851 DOI: 10.1128/aac.00695-23] [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: 05/25/2023] [Accepted: 11/10/2023] [Indexed: 01/11/2024] Open
Abstract
Carbapenem-resistant Enterobacteriaceae (CREs) are described by the Centers for Disease Control as an urgent threat, and there is a critical need for new therapeutic agents able to treat infections caused by these pathogens. Herein, we describe the microbiological profile, the mechanism f action, and the in vitro safety as well as the pharmacokinetic (PK)/PD profile of SMT-738, a small molecule belonging to a new chemical class. SMT-738 is active against Enterobacterales [including multi-drug-resistant Escherichia coli with 90% of isolates having a minimum inhibitory concentration (MIC90) of 1 µg/mL and Klebsiella pneumoniae 2 µg/mL] and inactive against a broad panel of Gram-negative and Gram-positive pathogens. SMT-738 displays rapid bactericidal activity (2-4 h) and has a low propensity for resistance development (less than ~10-9). Characterization of resistant mutants following exposure to SMT-738 identified mutations within the lipoprotein transport complex (LolCDE), a clinically unexploited and essential bacterial molecular target in Gram-negative bacteria. SMT-738 has a promising in vitro toxicology profile. Furthermore, PK studies demonstrated that when dosed intravenously, SMT-738 maintained exposure levels across infection sites (bloodstream/urinary tract/lung). Proof-of-concept studies across multiple murine in vivo infection models (bloodstream/pneumonia/urinary tract) demonstrated that SMT-738 significantly reduced the bacterial burden compared to baseline and vehicle control. SMT-738 represents a promising novel drug candidate being developed to address clinically challenging serious life-threatening infections caused by highly resistant Enterobacteriaceae including CRE.
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Affiliation(s)
| | - N. Khan
- Summit Therapeutics, The Works, Unity Campus, Cambridge, United Kingdom
| | - T. Duffy
- Summit Therapeutics, The Works, Unity Campus, Cambridge, United Kingdom
| | - C. Coward
- Summit Therapeutics, The Works, Unity Campus, Cambridge, United Kingdom
| | - T. Avis
- Summit Therapeutics, The Works, Unity Campus, Cambridge, United Kingdom
| | - O. Abdulle
- Summit Therapeutics, The Works, Unity Campus, Cambridge, United Kingdom
| | - C.-M. Li
- Summit Therapeutics, Menlo Park, California, USA
| | - C. S. Mason
- Summit Therapeutics, The Works, Unity Campus, Cambridge, United Kingdom
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8
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Lehman KM, May KL, Marotta J, Grabowicz M. Genetic analysis reveals a robust and hierarchical recruitment of the LolA chaperone to the LolCDE lipoprotein transporter. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.08.566237. [PMID: 37986794 PMCID: PMC10659402 DOI: 10.1101/2023.11.08.566237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2023]
Abstract
The outer membrane (OM) is an essential organelle of Gram-negative bacteria. Lipoproteins are key to building the OM, performing essential functions in several OM assembly machines. Lipoproteins mature in the inner membrane (IM) and are then trafficked to the OM. In Escherichia coli, the LolCDE transporter is needed to extract lipoproteins from the IM to begin trafficking. Lipoproteins are then transferred from LolCDE to the periplasmic chaperone LolA which ferries them to the OM for insertion by LolB. LolA recruitment by LolC is an essential trafficking step. Structural and biochemical studies suggested that two regions (termed Hook and Pad) within a periplasmic loop of LolC worked in tandem to recruit LolA, leading to a bipartite model for recruitment. Here, we genetically examine the LolC periplasmic loop in vivo using E. coli. Our findings challenge the bipartite interaction model. We show that while the Hook is essential for lipoprotein trafficking in vivo, lipoproteins are still efficiently trafficked when the Pad residues are inactivated. We show with AlphaFold2 multimer modeling that Hook:LolA interactions are likely universal among diverse Gram-negative bacteria. Conversely, Pad:LolA interactions vary across phyla. Our in vivo data redefine LolC:LolA recruitment into a hierarchical interaction model. We propose that the Hook is the major player in LolA recruitment, while the Pad plays an ancillary role that is important for efficiency but is ultimately dispensable. Our findings expand the understanding of a fundamental step in essential lipoprotein trafficking and have implications for efforts to develop new antibacterials that target LolCDE.
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Affiliation(s)
- Kelly M. Lehman
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
- Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
- Kelly M. Lehman and Kerrie L. May contributed equally to this work. Author order was determined alphabetically
| | - Kerrie L. May
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
- Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
- Kelly M. Lehman and Kerrie L. May contributed equally to this work. Author order was determined alphabetically
| | - Julianna Marotta
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
- Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Marcin Grabowicz
- Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia, USA
- Division of Infectious Diseases, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA
- Emory Antibiotic Resistance Center, Emory University School of Medicine, Atlanta, Georgia, USA
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9
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Liu G, Catacutan DB, Rathod K, Swanson K, Jin W, Mohammed JC, Chiappino-Pepe A, Syed SA, Fragis M, Rachwalski K, Magolan J, Surette MG, Coombes BK, Jaakkola T, Barzilay R, Collins JJ, Stokes JM. Deep learning-guided discovery of an antibiotic targeting Acinetobacter baumannii. Nat Chem Biol 2023; 19:1342-1350. [PMID: 37231267 DOI: 10.1038/s41589-023-01349-8] [Citation(s) in RCA: 52] [Impact Index Per Article: 52.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 04/25/2023] [Indexed: 05/27/2023]
Abstract
Acinetobacter baumannii is a nosocomial Gram-negative pathogen that often displays multidrug resistance. Discovering new antibiotics against A. baumannii has proven challenging through conventional screening approaches. Fortunately, machine learning methods allow for the rapid exploration of chemical space, increasing the probability of discovering new antibacterial molecules. Here we screened ~7,500 molecules for those that inhibited the growth of A. baumannii in vitro. We trained a neural network with this growth inhibition dataset and performed in silico predictions for structurally new molecules with activity against A. baumannii. Through this approach, we discovered abaucin, an antibacterial compound with narrow-spectrum activity against A. baumannii. Further investigations revealed that abaucin perturbs lipoprotein trafficking through a mechanism involving LolE. Moreover, abaucin could control an A. baumannii infection in a mouse wound model. This work highlights the utility of machine learning in antibiotic discovery and describes a promising lead with targeted activity against a challenging Gram-negative pathogen.
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Affiliation(s)
- Gary Liu
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
| | - Denise B Catacutan
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
| | - Khushi Rathod
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
| | - Kyle Swanson
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Wengong Jin
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Jody C Mohammed
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
| | - Anush Chiappino-Pepe
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Saad A Syed
- Department of Medicine, Department of Biochemistry and Biomedical Sciences, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Meghan Fragis
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, Canada
| | - Kenneth Rachwalski
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
| | - Jakob Magolan
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, Canada
| | - Michael G Surette
- Department of Medicine, Department of Biochemistry and Biomedical Sciences, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Brian K Coombes
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
| | - Tommi Jaakkola
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Regina Barzilay
- Computer Science and Artificial Intelligence Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA
- Abdul Latif Jameel Clinic for Machine Learning in Health, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - James J Collins
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA.
- Abdul Latif Jameel Clinic for Machine Learning in Health, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Department of Biological Engineering, Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA.
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
| | - Jonathan M Stokes
- Department of Biochemistry and Biomedical Sciences, Michael G. DeGroote Institute for Infectious Disease Research, David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada.
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10
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Remm S, De Vecchis D, Schöppe J, Hutter CAJ, Gonda I, Hohl M, Newstead S, Schäfer LV, Seeger MA. Structural basis for triacylglyceride extraction from mycobacterial inner membrane by MFS transporter Rv1410. Nat Commun 2023; 14:6449. [PMID: 37833269 PMCID: PMC10576003 DOI: 10.1038/s41467-023-42073-0] [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: 09/28/2023] [Indexed: 10/15/2023] Open
Abstract
Mycobacterium tuberculosis is protected from antibiotic therapy by a multi-layered hydrophobic cell envelope. Major facilitator superfamily (MFS) transporter Rv1410 and the periplasmic lipoprotein LprG are involved in transport of triacylglycerides (TAGs) that seal the mycomembrane. Here, we report a 2.7 Å structure of a mycobacterial Rv1410 homologue, which adopts an outward-facing conformation and exhibits unusual transmembrane helix 11 and 12 extensions that protrude ~20 Å into the periplasm. A small, very hydrophobic cavity suitable for lipid transport is constricted by a functionally important ion-lock likely involved in proton coupling. Combining mutational analyses and MD simulations, we propose that TAGs are extracted from the core of the inner membrane into the central cavity via lateral clefts present in the inward-facing conformation. The functional role of the periplasmic helix extensions is to channel the extracted TAG into the lipid binding pocket of LprG.
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Affiliation(s)
- Sille Remm
- Institute of Medical Microbiology, University of Zurich, Zürich, Switzerland
| | - Dario De Vecchis
- Center for Theoretical Chemistry, Ruhr University Bochum, Bochum, Germany
| | - Jendrik Schöppe
- Institute of Biochemistry, University of Zurich, Zürich, Switzerland
- Global Research Technologies, Novo Nordisk A/S, Måløv, Denmark
| | - Cedric A J Hutter
- Institute of Medical Microbiology, University of Zurich, Zürich, Switzerland
- Linkster Therapeutics, Zürich, Switzerland
| | - Imre Gonda
- Institute of Medical Microbiology, University of Zurich, Zürich, Switzerland
| | - Michael Hohl
- Institute of Medical Microbiology, University of Zurich, Zürich, Switzerland
- Department of Infectious Disease, Imperial College London, London, United Kingdom
| | - Simon Newstead
- Department of Biochemistry, University of Oxford, Oxford, United Kingdom
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford, United Kingdom
| | - Lars V Schäfer
- Center for Theoretical Chemistry, Ruhr University Bochum, Bochum, Germany.
| | - Markus A Seeger
- Institute of Medical Microbiology, University of Zurich, Zürich, Switzerland.
- National Center for Mycobacteria, Zurich, Switzerland.
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11
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Meng YY, Peng JH, Qian J, Fei FL, Guo YY, Pan YJ, Zhao Y, Liu HQ. The two-component system expression patterns and immune regulatory mechanism of Vibrio parahaemolyticus with different genotypes at the early stage of infection in THP-1 cells. mSystems 2023; 8:e0023723. [PMID: 37432027 PMCID: PMC10469919 DOI: 10.1128/msystems.00237-23] [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: 03/13/2023] [Accepted: 06/02/2023] [Indexed: 07/12/2023] Open
Abstract
Vibrio parahaemolyticus must endure various challenging circumstances while being swallowed by phagocytes of the innate immune system. Moreover, bacteria should recognize and react to environmental signals quickly in host cells. Two-component system (TCS) is an important way for bacteria to perceive external environmental signals and transmit them to the interior to trigger the associated regulatory mechanism. However, the regulatory function of V. parahaemolyticus TCS in innate immune cells is unclear. Here, the expression patterns of TCS in V. parahaemolyticus-infected THP-1 cell-derived macrophages at the early stage were studied for the first time. Based on protein-protein interaction network analysis, we mined and analyzed seven critical TCS genes with excellent research value in the V. parahaemolyticus regulating macrophages, as shown below. VP1503, VP1502, VPA0021, and VPA0182 could regulate the ATP-binding-cassette (ABC) transport system. VP1735, uvrY, and peuR might interact with thermostable hemolysin proteins, DNA cleavage-related proteins, and TonB-dependent siderophore enterobactin receptor, respectively, which may assist V. parahaemolyticus in infected macrophages. Subsequently, the potential immune escape pathways of V. parahaemolyticus regulating macrophages were explored by RNA-seq. The results showed that V. parahaemolyticus might infect macrophages by controlling apoptosis, actin cytoskeleton, and cytokines. In addition, we found that the TCS (peuS/R) could enhance the toxicity of V. parahaemolyticus to macrophages and might contribute to the activation of macrophage apoptosis. IMPORTANCE This study could offer crucial new insights into the pathogenicity of V. parahaemolyticus without tdh and trh genes. In addition, we also provided a novel direction of inquiry into the pathogenic mechanism of V. parahaemolyticus and suggested several TCS key genes that may assist V. parahaemolyticus in innate immune regulation and interaction.
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Affiliation(s)
- Yuan-Yuan Meng
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Jun-Hui Peng
- Shanghai Fisheries Research Institute, Shanghai Fisheries Technical Extension Station, Shanghai, China
| | - Jiang Qian
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Fu-Lin Fei
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Ying-Ying Guo
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
| | - Ying-Jie Pan
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
- Laboratory of Quality & Safety Risk Assessment for Aquatic Products on Storage and Preservation, Ministry of Agriculture and Rural Affairs, Shanghai, China
- Shanghai Engineering Research Center of Aquatic-Product Processing & Preservation, Shanghai, China
| | - Yong Zhao
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
- Laboratory of Quality & Safety Risk Assessment for Aquatic Products on Storage and Preservation, Ministry of Agriculture and Rural Affairs, Shanghai, China
- Shanghai Engineering Research Center of Aquatic-Product Processing & Preservation, Shanghai, China
| | - Hai-Quan Liu
- College of Food Science and Technology, Shanghai Ocean University, Shanghai, China
- Laboratory of Quality & Safety Risk Assessment for Aquatic Products on Storage and Preservation, Ministry of Agriculture and Rural Affairs, Shanghai, China
- Shanghai Engineering Research Center of Aquatic-Product Processing & Preservation, Shanghai, China
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12
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Furlanetto V, Divne C. LolA and LolB from the plant-pathogen Xanthomonas campestris forms a stable heterodimeric complex in the absence of lipoprotein. Front Microbiol 2023; 14:1216799. [PMID: 37502397 PMCID: PMC10368991 DOI: 10.3389/fmicb.2023.1216799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 06/26/2023] [Indexed: 07/29/2023] Open
Abstract
The Gram-negative bacterium Xanthomonas campestris is one of the most problematic phytopathogens, and especially the pathovar campestris (Xcc) that causes a devastating plant disease known as black rot and it is of considerable interest to understand the molecular mechanisms that enable virulence and pathogenicity. Gram-negative bacteria depend on lipoproteins (LPs) that serve many important functions including control of cell shape and integrity, biogenesis of the outer membrane (OM) and establishment of transport pathways across the periplasm. The LPs are localized to the OM where they are attached via a lipid anchor by a process known as the localization of lipoprotein (Lol) pathway. Once a lipid anchor has been synthesized on the nascent LP, the Lol pathway is initiated by a membrane-bound ABC transporter that extracts the lipid anchor of the LP from the IM. The ABC extractor presents the extracted LP to the transport protein LolA, which binds the anchor and thereby shields it from the hydrophilic periplasmic milieu. It is assumed that LolA then carries the LP across the periplasm to the OM. At the periplasmic face of the OM, the LP cargo is delivered to LolB, which completes the Lol pathway by inserting the LP anchor in the inner leaflet of the outer membrane. Earlier studies have shown that loss of Xcc LolA or LolB leads to decreased virulence and pathogenicity during plant infection, which motivates studies to better understand the Lol system in Xcc. In this study, we report the first experimental structure of a complex between LolA and LolB. The crystal structure reveals a stable LolA-LolB complex in the absence of LP. The structural integrity of the LP-free complex is safeguarded by specific protein-protein interactions that do not coincide with interactions predicted to participate in lipid binding. The results allow us to identify structural determinants that enable Xcc LolA to dock with LolB and initiate LP transfer.
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13
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McClain MS, Bryant KN, McDonald WH, Algood HMS, Cover TL. Identification of an Essential LolD-Like Protein in Helicobacter pylori. J Bacteriol 2023; 205:e0005223. [PMID: 36971548 PMCID: PMC10127691 DOI: 10.1128/jb.00052-23] [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: 02/03/2023] [Accepted: 02/24/2023] [Indexed: 03/29/2023] Open
Abstract
The localization of lipoprotein (Lol) system is used by Gram-negative bacteria to export lipoproteins to the outer membrane. Lol proteins and models of how Lol transfers lipoproteins from the inner to the outer membrane have been extensively characterized in the model organism Escherichia coli, but in numerous bacterial species, lipoprotein synthesis and export pathways deviate from the E. coli paradigm. For example, in the human gastric bacterium Helicobacter pylori, a homolog of the E. coli outer membrane component LolB is not found, E. coli LolC and LolE correspond to a single inner membrane component (LolF), and a homolog of the E. coli cytoplasmic ATPase LolD has not been identified. In the present study, we sought to identify a LolD-like protein in H. pylori. We used affinity-purification mass spectrometry to identify interaction partners of the H. pylori ATP-binding cassette (ABC) family permease LolF and identified the ABC family ATP-binding protein HP0179 as its interaction partner. We engineered H. pylori to conditionally express HP0179 and showed that HP0179 and its conserved ATP binding and ATP hydrolysis motifs are essential for H. pylori growth. We then performed affinity purification-mass spectrometry using HP0179 as the bait and identified LolF as its interaction partner. These results indicate that H. pylori HP0179 is a LolD-like protein and provide a more complete understanding of lipoprotein localization processes in H. pylori, a bacterium in which the Lol system deviates from the E. coli paradigm. IMPORTANCE Lipoproteins are critical in Gram-negative-bacteria for cell surface assembly of LPS, insertion of outer membrane proteins, and sensing envelope stress. Lipoproteins also contribute to bacterial pathogenesis. For many of these functions, lipoproteins must localize to the Gram-negative outer membrane. Transporting lipoproteins to the outer membrane involves the Lol sorting pathway. Detailed analyses of the Lol pathway have been performed in the model organism Escherichia coli, but many bacteria utilize altered components or are missing essential components of the E. coli Lol pathway. Identifying a LolD-like protein in Helicobacter pylori is important to better understand the Lol pathway in diverse bacterial classes. This becomes particularly relevant as lipoprotein localization is targeted for antimicrobial development.
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Affiliation(s)
- Mark S. McClain
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection Immunology and Inflammation, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Kaeli N. Bryant
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - W. Hayes McDonald
- Proteomics Laboratory, Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Holly M. Scott Algood
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection Immunology and Inflammation, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
| | - Timothy L. Cover
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Vanderbilt Institute for Infection Immunology and Inflammation, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Veterans Affairs Tennessee Valley Healthcare System, Nashville, Tennessee, USA
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14
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Jaiman D, Nagampalli R, Persson K. A comparative analysis of lipoprotein transport proteins: LolA and LolB from Vibrio cholerae and LolA from Porphyromonas gingivalis. Sci Rep 2023; 13:6605. [PMID: 37095149 PMCID: PMC10126205 DOI: 10.1038/s41598-023-33705-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 04/18/2023] [Indexed: 04/26/2023] Open
Abstract
In Gram-negative bacteria, N-terminal lipidation is a signal for protein trafficking from the inner membrane (IM) to the outer membrane (OM). The IM complex LolCDE extracts lipoproteins from the membrane and moves them to the chaperone LolA. The LolA-lipoprotein complex crosses the periplasm after which the lipoprotein is anchored to the OM. In γ-proteobacteria anchoring is assisted by the receptor LolB, while a corresponding protein has not been identified in other phyla. In light of the low sequence similarity between Lol-systems from different phyla and that they may use different Lol components, it is crucial to compare representative proteins from several species. Here we present a structure-function study of LolA and LolB from two phyla: LolA from Porphyromonas gingivalis (phylum bacteroidota), and LolA and LolB from Vibrio cholerae (phylum proteobacteria). Despite large sequence differences, the LolA structures are very similar, hence structure and function have been conserved throughout evolution. However, an Arg-Pro motif crucial for function in γ-proteobacteria has no counterpart in bacteroidota. We also show that LolA from both phyla bind the antibiotic polymyxin B whereas LolB does not. Collectively, these studies will facilitate the development of antibiotics as they provide awareness of both differences and similarities across phyla.
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Affiliation(s)
- Deepika Jaiman
- Umeå Centre for Microbial Research (UCMR), Umeå, Sweden
- Department of Chemistry, Umeå University, 90187, Umeå, Sweden
| | - Raghavendra Nagampalli
- Umeå Centre for Microbial Research (UCMR), Umeå, Sweden
- Department of Chemistry, Umeå University, 90187, Umeå, Sweden
| | - Karina Persson
- Umeå Centre for Microbial Research (UCMR), Umeå, Sweden.
- Department of Chemistry, Umeå University, 90187, Umeå, Sweden.
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15
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Vercruysse M, Dylus D. Special issue of BBA reviews — Molecular Cell Research: The Gram-negative envelope and potential targets for novel antibiotics. BIOCHIMICA ET BIOPHYSICA ACTA (BBA) - MOLECULAR CELL RESEARCH 2023; 1870:119472. [PMID: 37011731 DOI: 10.1016/j.bbamcr.2023.119472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 02/08/2023] [Accepted: 02/27/2023] [Indexed: 04/03/2023]
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16
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Bilsing FL, Anlauf MT, Hachani E, Khosa S, Schmitt L. ABC Transporters in Bacterial Nanomachineries. Int J Mol Sci 2023; 24:ijms24076227. [PMID: 37047196 PMCID: PMC10094684 DOI: 10.3390/ijms24076227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/18/2023] [Accepted: 03/23/2023] [Indexed: 03/29/2023] Open
Abstract
Members of the superfamily of ABC transporters are found in all domains of life. Most of these primary active transporters act as isolated entities and export or import their substrates in an ATP-dependent manner across biological membranes. However, some ABC transporters are also part of larger protein complexes, so-called nanomachineries that catalyze the vectorial transport of their substrates. Here, we will focus on four bacterial examples of such nanomachineries: the Mac system providing drug resistance, the Lpt system catalyzing vectorial LPS transport, the Mla system responsible for phospholipid transport, and the Lol system, which is required for lipoprotein transport to the outer membrane of Gram-negative bacteria. For all four systems, we tried to summarize the existing data and provide a structure-function analysis highlighting the mechanistical aspect of the coupling of ATP hydrolysis to substrate translocation.
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17
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Dutta A, Prasad Kanaujia S. MlaC belongs to a unique class of non-canonical substrate-binding proteins and follows a novel phospholipid-binding mechanism. J Struct Biol 2022; 214:107896. [PMID: 36084896 DOI: 10.1016/j.jsb.2022.107896] [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: 06/27/2022] [Revised: 09/01/2022] [Accepted: 09/02/2022] [Indexed: 12/30/2022]
Abstract
The outer membrane (OM) of Gram-negative bacteria acts as a formidable barrier against a plethora of detrimental compounds owing to its asymmetric nature. This is because the OM possesses lipopolysaccharides (LPSs) in the outer leaflet and phospholipids (PLs) in the inner leaflet. The maintenance of lipid asymmetry (Mla) system is involved in preserving the distribution of PLs in OM. The periplasmic component of the system MlaC serves as the substrate-binding protein (SBP) that shuttles PLs between the inner and outer membranes. However, an in-depth report highlighting its mechanism of ligand binding is still lacking. This study reports the crystal structure of MlaC from Escherichia coli (EcMlaC) at a resolution of 2.5 Å in a quasi-open state, complexed with PL. The structural analysis reveals that EcMlaC and orthologs comprise two major domains, viz. nuclear transport factor 2-like (NTF2-like) and phospholipid-binding protein (PBP). Each domain can be further divided into two subdomains arranged in a discontinuous fashion. This study further reveals that EcMlaC is polyspecific in nature and follows a reverse mechanism of the opening of the substrate-binding site during the ligand binding. Furthermore, MlaC can bind two PLs by forming subsites in the binding pocket. These findings, altogether, have led to the proposition of the unique "segmented domain movement" mechanism of PL binding, not reported for any known SBP to date. Further, unlike typical SBPs, MlaC has originated from a cystatin-like fold. Overall, this study establishes MlaC to be a non-canonical SBP with a unique ligand-binding mechanism.
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Affiliation(s)
- Angshu Dutta
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati - 781039, Assam, India
| | - Shankar Prasad Kanaujia
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati - 781039, Assam, India.
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18
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Bei W, Luo Q, Shi H, Zhou H, Zhou M, Zhang X, Huang Y. Cryo-EM structures of LolCDE reveal the molecular mechanism of bacterial lipoprotein sorting in Escherichia coli. PLoS Biol 2022; 20:e3001823. [PMID: 36228045 PMCID: PMC9595528 DOI: 10.1371/journal.pbio.3001823] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 10/25/2022] [Accepted: 09/12/2022] [Indexed: 11/06/2022] Open
Abstract
Bacterial lipoproteins perform a diverse array of functions including bacterial envelope biogenesis and microbe–host interactions. Lipoproteins in gram-negative bacteria are sorted to the outer membrane (OM) via the localization of lipoproteins (Lol) export pathway. The ATP-binding cassette (ABC) transporter LolCDE initiates the Lol pathway by selectively extracting and transporting lipoproteins for trafficking. Here, we report cryo-EM structures of LolCDE in apo, lipoprotein-bound, and AMPPNP-bound states at a resolution of 3.5 to 4.2 Å. Structure-based disulfide crosslinking, photo-crosslinking, and functional complementation assay verify the apo-state structure and reveal the molecular details regarding substrate selectivity and substrate entry route. Our studies snapshot 3 functional states of LolCDE in a transport cycle, providing deep insights into the mechanisms that underlie LolCDE-mediated lipoprotein sorting in E. coli. Lipoproteins in Gram-negative bacteria are sorted to the outer membrane via the Lol export pathway. The ABC transporter LolCDE initiates this pathway by selectively extracting and transporting lipoproteins for trafficking; this study provides a structural basis for the LolCDE-mediated bacterial lipoprotein sorting, with implications for novel antibiotic design against Gram-negative bacterial pathogens.
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Affiliation(s)
- Weiwei Bei
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qingshan Luo
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Huigang Shi
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Haizhen Zhou
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Min Zhou
- Institute of Bio-analytical Chemistry, School of Chemical Engineering, Nanjing University of Science and Technology, No.200 Xiao Ling Wei Street, Nanjing, China
| | - Xinzheng Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- * E-mail: (XZ); (YH)
| | - Yihua Huang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- * E-mail: (XZ); (YH)
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19
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How to take your sticky proteins out safely. Proc Natl Acad Sci U S A 2022. [DOI: 10.1073/pnas.2213816119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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20
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Structural basis of lipoprotein recognition by the bacterial Lol trafficking chaperone LolA. Proc Natl Acad Sci U S A 2022; 119:e2208662119. [PMID: 36037338 PMCID: PMC9457489 DOI: 10.1073/pnas.2208662119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Lipoproteins in gram-negative bacteria underpin the formation and maintenance of the outer membrane that constitutes a vital protective barrier against antibiotics and other noxious molecules. An essential transport system comprising the LolABCDE proteins is required to traffic lipoproteins to the outer membrane. Following maturation on the inner membrane and extraction by the LolCDE transporter, lipoproteins are passed to the chaperone LolA that carries them across the periplasm prior to insertion into the outer membrane by the LolB receptor. Here, we report the molecular details of lipoprotein interaction with the chaperone LolA, a key intermediate located at the heart of the Lol pathway. The structure provides valuable insights into this important system and could be exploited to develop new antimicrobials. In gram-negative bacteria, lipoproteins are vital structural components of the outer membrane (OM) and crucial elements of machineries central to the physiology of the cell envelope. A dedicated apparatus, the Lol system, is required for the correct localization of OM lipoproteins and is essential for viability. The periplasmic chaperone LolA is central to this trafficking pathway, accepting triacylated lipoproteins from the inner membrane transporter LolCDE, before carrying them across the periplasm to the OM receptor LolB. Here, we report a crystal structure of liganded LolA, generated in vivo, revealing the molecular details of lipoprotein association. The structure highlights how LolA, initially primed to receive lipoprotein by interaction with LolC, further opens to accommodate the three ligand acyl chains in a precise conformation within its cavity. LolA forms extensive interactions with the acyl chains but not with any residue of the cargo, explaining the chaperone’s ability to transport structurally diverse lipoproteins. Structural characterization of a ligandedLolA variant incapable of lipoprotein release reveals aberrant association, demonstrating the importance of the LolCDE-coordinated, sequential opening of LolA for inserting lipoprotein in a manner productive for subsequent trafficking. Comparison with existing structures of LolA in complex with LolC or LolCDE reveals substantial overlap of the lipoprotein and LolC binding sites within the LolA cavity, demonstrating that insertion of lipoprotein acyl chains physically disengages the chaperone protein from the transporter by perturbing interaction with LolC. Taken together, our data provide a key step toward a complete understanding of a fundamentally important trafficking pathway.
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21
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Abstract
The outer membrane (OM) of Gram-negative bacteria is an essential organelle that acts as a formidable barrier to antibiotics. Increasingly prevalent resistance to existing drugs has exacerbated the need for antibiotic discovery efforts targeting the OM. Acylated proteins, known as lipoproteins, are essential in every pathway needed to build the OM. The central role of OM lipoproteins makes their biogenesis a uniquely attractive therapeutic target, but it also complicates in vivo identification of on-pathway inhibitors, as inhibition of OM lipoprotein biogenesis broadly disrupts OM assembly. Here, we use genetics to probe the eight essential proteins involved in OM lipoprotein maturation and trafficking. We define a biological signature consisting of three simple assays that can characteristically identify OM lipoprotein biogenesis defects in vivo. We find that several known chemical inhibitors of OM lipoprotein biogenesis conform to the biological signature. We also examine MAC13243, a proposed inhibitor of OM lipoprotein biogenesis, and find that it fails to conform to the biological signature. Indeed, we demonstrate that MAC13243 activity relies entirely on a target outside of the OM lipoprotein biogenesis pathway. Hence, our signature offers simple tools to easily assess whether antibiotic lead compounds target an essential pathway that is the hub of OM assembly.
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22
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Liu S, Lu H, Zhang S, Shi Y, Chen Q. Phages against Pathogenic Bacterial Biofilms and Biofilm-Based Infections: A Review. Pharmaceutics 2022; 14:pharmaceutics14020427. [PMID: 35214158 PMCID: PMC8875263 DOI: 10.3390/pharmaceutics14020427] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/07/2022] [Accepted: 02/08/2022] [Indexed: 02/01/2023] Open
Abstract
Bacterial biofilms formed by pathogens are known to be hundreds of times more resistant to antimicrobial agents than planktonic cells, making it extremely difficult to cure biofilm-based infections despite the use of antibiotics, which poses a serious threat to human health. Therefore, there is an urgent need to develop promising alternative antimicrobial therapies to reduce the burden of drug-resistant bacterial infections caused by biofilms. As natural enemies of bacteria, bacteriophages (phages) have the advantages of high specificity, safety and non-toxicity, and possess great potential in the defense and removal of pathogenic bacterial biofilms, which are considered to be alternatives to treat bacterial diseases. This work mainly reviews the composition, structure and formation process of bacterial biofilms, briefly discusses the interaction between phages and biofilms, and summarizes several strategies based on phages and their derivatives against biofilms and drug-resistant bacterial infections caused by biofilms, serving the purpose of developing novel, safe and effective treatment methods against biofilm-based infections and promoting the application of phages in maintaining human health.
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Affiliation(s)
| | | | | | - Ying Shi
- Correspondence: (Y.S.); (Q.C.); Tel.: +86-139-6717-1522 (Y.S.)
| | - Qihe Chen
- Correspondence: (Y.S.); (Q.C.); Tel.: +86-139-6717-1522 (Y.S.)
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23
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Alcorlo M, Martínez-Caballero S, Molina R, Hermoso JA. Regulation of Lytic Machineries by the FtsEX Complex in the Bacterial Divisome. Subcell Biochem 2022; 99:285-315. [PMID: 36151380 DOI: 10.1007/978-3-031-00793-4_9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The essential membrane complex FtsE/FtsX (FtsEX), belonging to the ABC transporter superfamily and widespread among bacteria, plays a relevant function in some crucial cell wall remodeling processes such as cell division, elongation, or sporulation. FtsEX plays a double role by recruiting proteins to the divisome apparatus and by regulating lytic activity of the cell wall hydrolases required for daughter cell separation. Interestingly, FtsEX does not act as a transporter but uses the ATPase activity of FtsE to mechanically transmit a signal from the cytosol, through the membrane, to the periplasm that activates the attached hydrolases. While the complete molecular details of such mechanism are not yet known, evidence has been recently reported that clarify essential aspects of this complex system. In this chapter we will present recent structural advances on this topic. The three-dimensional structure of FtsE, FtsX, and some of the lytic enzymes or their cognate regulators revealed an unexpected scenario in which a delicate set of intermolecular interactions, conserved among different bacterial genera, could be at the core of this regulatory mechanism providing exquisite control in both space and time of this central process to assist bacterial survival.
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Affiliation(s)
- Martín Alcorlo
- Department of Crystallography and Structural Biology, Institute of Physical Chemistry "Rocasolano", CSIC, Madrid, Spain
| | - Siseth Martínez-Caballero
- Department of Crystallography and Structural Biology, Institute of Physical Chemistry "Rocasolano", CSIC, Madrid, Spain
- Department of Chemistry of Biomacromolecules, Universidade Nacional Autonoma de Mexico, Ciudad de México, Mexico
| | - Rafael Molina
- Department of Crystallography and Structural Biology, Institute of Physical Chemistry "Rocasolano", CSIC, Madrid, Spain
| | - Juan A Hermoso
- Department of Crystallography and Structural Biology, Institute of Physical Chemistry "Rocasolano", CSIC, Madrid, Spain.
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24
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Szabó G, Schulz F, Manzano-Marín A, Toenshoff ER, Horn M. Evolutionarily recent dual obligatory symbiosis among adelgids indicates a transition between fungus- and insect-associated lifestyles. THE ISME JOURNAL 2022; 16:247-256. [PMID: 34294881 PMCID: PMC8692619 DOI: 10.1038/s41396-021-01056-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 06/28/2021] [Accepted: 07/01/2021] [Indexed: 02/07/2023]
Abstract
Adelgids (Insecta: Hemiptera: Adelgidae) form a small group of insects but harbor a surprisingly diverse set of bacteriocyte-associated endosymbionts, which suggest multiple replacement and acquisition of symbionts over evolutionary time. Specific pairs of symbionts have been associated with adelgid lineages specialized on different secondary host conifers. Using a metagenomic approach, we investigated the symbiosis of the Adelges laricis/Adelges tardus species complex containing betaproteobacterial ("Candidatus Vallotia tarda") and gammaproteobacterial ("Candidatus Profftia tarda") symbionts. Genomic characteristics and metabolic pathway reconstructions revealed that Vallotia and Profftia are evolutionary young endosymbionts, which complement each other's role in essential amino acid production. Phylogenomic analyses and a high level of genomic synteny indicate an origin of the betaproteobacterial symbiont from endosymbionts of Rhizopus fungi. This evolutionary transition was accompanied with substantial loss of functions related to transcription regulation, secondary metabolite production, bacterial defense mechanisms, host infection, and manipulation. The transition from fungus to insect endosymbionts extends our current framework about evolutionary trajectories of host-associated microbes.
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Affiliation(s)
- Gitta Szabó
- Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria.
- Department of Internal Medicine and Oncology, Semmelweis University, Budapest, Hungary.
| | - Frederik Schulz
- Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
- US Department of Energy (DOE) Joint Genome Institute, Berkeley, CA, USA
| | - Alejandro Manzano-Marín
- Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
| | - Elena Rebecca Toenshoff
- Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
- Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Matthias Horn
- Department of Microbiology and Ecosystem Science, Centre for Microbiology and Environmental Systems Science, University of Vienna, Vienna, Austria
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25
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Zhang Z, Huang Z, Tong J, Wu Q, Pan Y, Malakar PK, Zhao Y. An outlook for food sterilization technology: targeting the outer membrane of foodborne gram-negative pathogenic bacteria. Curr Opin Food Sci 2021. [DOI: 10.1016/j.cofs.2021.02.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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26
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Graham CLB, Newman H, Gillett FN, Smart K, Briggs N, Banzhaf M, Roper DI. A Dynamic Network of Proteins Facilitate Cell Envelope Biogenesis in Gram-Negative Bacteria. Int J Mol Sci 2021; 22:12831. [PMID: 34884635 PMCID: PMC8657477 DOI: 10.3390/ijms222312831] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Revised: 11/02/2021] [Accepted: 11/03/2021] [Indexed: 01/01/2023] Open
Abstract
Bacteria must maintain the ability to modify and repair the peptidoglycan layer without jeopardising its essential functions in cell shape, cellular integrity and intermolecular interactions. A range of new experimental techniques is bringing an advanced understanding of how bacteria regulate and achieve peptidoglycan synthesis, particularly in respect of the central role played by complexes of Sporulation, Elongation or Division (SEDs) and class B penicillin-binding proteins required for cell division, growth and shape. In this review we highlight relationships implicated by a bioinformatic approach between the outer membrane, cytoskeletal components, periplasmic control proteins, and cell elongation/division proteins to provide further perspective on the interactions of these cell division, growth and shape complexes. We detail the network of protein interactions that assist in the formation of peptidoglycan and highlight the increasingly dynamic and connected set of protein machinery and macrostructures that assist in creating the cell envelope layers in Gram-negative bacteria.
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Affiliation(s)
- Chris L. B. Graham
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (C.L.B.G.); (H.N.); (F.N.G.); (K.S.); (N.B.)
| | - Hector Newman
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (C.L.B.G.); (H.N.); (F.N.G.); (K.S.); (N.B.)
| | - Francesca N. Gillett
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (C.L.B.G.); (H.N.); (F.N.G.); (K.S.); (N.B.)
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK;
| | - Katie Smart
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (C.L.B.G.); (H.N.); (F.N.G.); (K.S.); (N.B.)
| | - Nicholas Briggs
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (C.L.B.G.); (H.N.); (F.N.G.); (K.S.); (N.B.)
| | - Manuel Banzhaf
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK;
| | - David I. Roper
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; (C.L.B.G.); (H.N.); (F.N.G.); (K.S.); (N.B.)
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27
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Alves Feliciano C, Eckenroth BE, Diaz OR, Doublié S, Shen A. A lipoprotein allosterically activates the CwlD amidase during Clostridioides difficile spore formation. PLoS Genet 2021; 17:e1009791. [PMID: 34570752 PMCID: PMC8496864 DOI: 10.1371/journal.pgen.1009791] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 10/07/2021] [Accepted: 08/23/2021] [Indexed: 11/19/2022] Open
Abstract
Spore-forming pathogens like Clostridioides difficile depend on germination to initiate infection. During gemination, spores must degrade their cortex layer, which is a thick, protective layer of modified peptidoglycan. Cortex degradation depends on the presence of the spore-specific peptidoglycan modification, muramic-∂-lactam (MAL), which is specifically recognized by cortex lytic enzymes. In C. difficile, MAL production depends on the CwlD amidase and its binding partner, the GerS lipoprotein. To gain insight into how GerS regulates CwlD activity, we solved the crystal structure of the CwlD:GerS complex. In this structure, a GerS homodimer is bound to two CwlD monomers such that the CwlD active sites are exposed. Although CwlD structurally resembles amidase_3 family members, we found that CwlD does not bind Zn2+ stably on its own, unlike previously characterized amidase_3 enzymes. Instead, GerS binding to CwlD promotes CwlD binding to Zn2+, which is required for its catalytic mechanism. Thus, in determining the first structure of an amidase bound to its regulator, we reveal stabilization of Zn2+ co-factor binding as a novel mechanism for regulating bacterial amidase activity. Our results further suggest that allosteric regulation by binding partners may be a more widespread mode for regulating bacterial amidase activity than previously thought. Spore germination is essential for many spore-forming pathogens to initiate infection. In order for spores to germinate, they must degrade a thick, protective layer of cell wall known as the cortex. The enzymes that digest this layer selectively recognize the spore-specific cell wall modification, muramic-∂-lactam (MAL). MAL is made in part through the activity of the CwlD amidase, which is found in all spore-forming bacteria. While Bacillus subtilis CwlD appears to have amidase activity on its own, Clostridioides difficile CwlD activity depends on its binding partner, the GerS lipoprotein. To understand why C. difficile CwlD requires GerS, we determined the X-ray crystal structure of the CwlD:GerS complex and discovered that GerS binds to a site distant from CwlD’s active site. We also found that GerS stabilizes CwlD binding to its co-factor, Zn2+, indicating that GerS allosterically activates CwlD amidase. Notably, regulation at the level of Zn2+ binding has not previously been described for bacterial amidases, and GerS is the first protein to be shown to allosterically activate an amidase. Since binding partners of bacterial amidases were only first discovered 15 years ago, our results suggest that diverse mechanisms remain to be discovered for these critical enzymes.
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Affiliation(s)
- Carolina Alves Feliciano
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Brian E. Eckenroth
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, United States of America
| | - Oscar R. Diaz
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Sylvie Doublié
- Department of Microbiology and Molecular Genetics, University of Vermont, Burlington, Vermont, United States of America
| | - Aimee Shen
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- * E-mail:
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28
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Sharma S, Zhou R, Wan L, Feng S, Song K, Xu C, Li Y, Liao M. Mechanism of LolCDE as a molecular extruder of bacterial triacylated lipoproteins. Nat Commun 2021; 12:4687. [PMID: 34344901 PMCID: PMC8333309 DOI: 10.1038/s41467-021-24965-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 07/16/2021] [Indexed: 02/07/2023] Open
Abstract
Lipoproteins are important for bacterial growth and antibiotic resistance. These proteins use lipid acyl chains attached to the N-terminal cysteine residue to anchor on the outer surface of cytoplasmic membrane. In Gram-negative bacteria, many lipoproteins are transported to the outer membrane (OM), a process dependent on the ATP-binding cassette (ABC) transporter LolCDE which extracts the OM-targeted lipoproteins from the cytoplasmic membrane. Lipid-anchored proteins pose a unique challenge for transport machinery as they have both hydrophobic lipid moieties and soluble protein component, and the underlying mechanism is poorly understood. Here we determined the cryo-EM structures of nanodisc-embedded LolCDE in the nucleotide-free and nucleotide-bound states at 3.8-Å and 3.5-Å resolution, respectively. The structural analyses, together with biochemical and mutagenesis studies, uncover how LolCDE recognizes its substrate by interacting with the lipid and N-terminal peptide moieties of the lipoprotein, and identify the amide-linked acyl chain as the key element for LolCDE interaction. Upon nucleotide binding, the transmembrane helices and the periplasmic domains of LolCDE undergo large-scale, asymmetric movements, resulting in extrusion of the captured lipoprotein. Comparison of LolCDE and MacB reveals the conserved mechanism of type VII ABC transporters and emphasizes the unique properties of LolCDE as a molecule extruder of triacylated lipoproteins.
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Affiliation(s)
- Stuti Sharma
- grid.38142.3c000000041936754XDepartment of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA USA
| | - Ruoyu Zhou
- grid.494629.40000 0004 8008 9315Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Li Wan
- grid.494629.40000 0004 8008 9315Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Shan Feng
- grid.494629.40000 0004 8008 9315Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - KangKang Song
- grid.168645.80000 0001 0742 0364Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA USA ,grid.168645.80000 0001 0742 0364Cryo-EM Core Facility, University of Massachusetts Medical School, Worcester, MA USA
| | - Chen Xu
- grid.168645.80000 0001 0742 0364Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA USA ,grid.168645.80000 0001 0742 0364Cryo-EM Core Facility, University of Massachusetts Medical School, Worcester, MA USA
| | - Yanyan Li
- grid.494629.40000 0004 8008 9315Key Laboratory of Structural Biology of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Maofu Liao
- grid.38142.3c000000041936754XDepartment of Cell Biology, Blavatnik Institute, Harvard Medical School, Boston, MA USA
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29
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Alav I, Kobylka J, Kuth MS, Pos KM, Picard M, Blair JMA, Bavro VN. Structure, Assembly, and Function of Tripartite Efflux and Type 1 Secretion Systems in Gram-Negative Bacteria. Chem Rev 2021; 121:5479-5596. [PMID: 33909410 PMCID: PMC8277102 DOI: 10.1021/acs.chemrev.1c00055] [Citation(s) in RCA: 95] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Indexed: 12/11/2022]
Abstract
Tripartite efflux pumps and the related type 1 secretion systems (T1SSs) in Gram-negative organisms are diverse in function, energization, and structural organization. They form continuous conduits spanning both the inner and the outer membrane and are composed of three principal components-the energized inner membrane transporters (belonging to ABC, RND, and MFS families), the outer membrane factor channel-like proteins, and linking the two, the periplasmic adaptor proteins (PAPs), also known as the membrane fusion proteins (MFPs). In this review we summarize the recent advances in understanding of structural biology, function, and regulation of these systems, highlighting the previously undescribed role of PAPs in providing a common architectural scaffold across diverse families of transporters. Despite being built from a limited number of basic structural domains, these complexes present a staggering variety of architectures. While key insights have been derived from the RND transporter systems, a closer inspection of the operation and structural organization of different tripartite systems reveals unexpected analogies between them, including those formed around MFS- and ATP-driven transporters, suggesting that they operate around basic common principles. Based on that we are proposing a new integrated model of PAP-mediated communication within the conformational cycling of tripartite systems, which could be expanded to other types of assemblies.
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Affiliation(s)
- Ilyas Alav
- Institute
of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Jessica Kobylka
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Miriam S. Kuth
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Klaas M. Pos
- Institute
of Biochemistry, Biocenter, Goethe Universität
Frankfurt, Max-von-Laue-Straße 9, D-60438 Frankfurt, Germany
| | - Martin Picard
- Laboratoire
de Biologie Physico-Chimique des Protéines Membranaires, CNRS
UMR 7099, Université de Paris, 75005 Paris, France
- Fondation
Edmond de Rothschild pour le développement de la recherche
Scientifique, Institut de Biologie Physico-Chimique, 75005 Paris, France
| | - Jessica M. A. Blair
- Institute
of Microbiology and Infection, College of Medical and Dental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Vassiliy N. Bavro
- School
of Life Sciences, University of Essex, Colchester, CO4 3SQ United Kingdom
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30
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Proteomic and Transcriptomic Analysis of Microviridae φX174 Infection Reveals Broad Upregulation of Host Escherichia coli Membrane Damage and Heat Shock Responses. mSystems 2021; 6:6/3/e00046-21. [PMID: 33975962 PMCID: PMC8125068 DOI: 10.1128/msystems.00046-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
A major part of the healthy human gut microbiome is the Microviridae bacteriophage, exemplified by the model φX174 phage, and their E. coli hosts. Although much has been learned from studying φX174 over the last half-century, until this work, the E. coli host response to infection has never been investigated in detail. Measuring host-bacteriophage dynamics is an important approach to understanding bacterial survival functions and responses to infection. The model Microviridae bacteriophage φX174 is endemic to the human gut and has been studied for over 70 years, but the host response to infection has never been investigated in detail. To address this gap in our understanding of this important interaction within our microbiome, we have measured host Escherichia coli C proteomic and transcriptomic response to φX174 infection. We used mass spectrometry and RNA sequencing (RNA-seq) to identify and quantify all 11 φX174 proteins and over 1,700 E. coli proteins, enabling us to comprehensively map host pathways involved in φX174 infection. Most notably, we see significant host responses centered on membrane damage and remodeling, cellular chaperone and translocon activity, and lipoprotein processing, which we speculate is due to the peptidoglycan-disruptive effects of the φX174 lysis protein E on MraY activity. We also observe the massive upregulation of small heat shock proteins IbpA/B, along with other heat shock pathway chaperones, and speculate on how the specific characteristics of holdase protein activity may be beneficial for viral infections. Together, this study enables us to begin to understand the proteomic and transcriptomic host responses of E. coli to Microviridae infections and contributes insights to the activities of this important model host-phage interaction. IMPORTANCE A major part of the healthy human gut microbiome is the Microviridae bacteriophage, exemplified by the model φX174 phage, and their E. coli hosts. Although much has been learned from studying φX174 over the last half-century, until this work, the E. coli host response to infection has never been investigated in detail. We reveal the proteomic and transcriptomic pathways differentially regulated during the φX174 infection cycle and uncover the details of a coordinated cellular response to membrane damage that results in increased lipoprotein processing and membrane trafficking, likely due to the phage antibiotic-like lysis protein. We also reveal that small heat shock proteins IbpA/B are massively upregulated during infection and that these holdase chaperones are highly conserved across the domains of life, indicating that reliance on them is likely widespread across viruses.
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31
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Souabni H, Batista Dos Santos W, Cece Q, Catoire LJ, Puvanendran D, Bavro VN, Picard M. Quantitative real-time analysis of the efflux by the MacAB-TolC tripartite efflux pump clarifies the role of ATP hydrolysis within mechanotransmission mechanism. Commun Biol 2021; 4:493. [PMID: 33888866 PMCID: PMC8062640 DOI: 10.1038/s42003-021-01997-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 03/18/2021] [Indexed: 02/07/2023] Open
Abstract
Tripartite efflux pumps built around ATP-binding cassette (ABC) transporters are membrane protein machineries that perform vectorial export of a large variety of drugs and virulence factors from Gram negative bacteria, using ATP-hydrolysis as energy source. Determining the number of ATP molecules consumed per transport cycle is essential to understanding the efficiency of substrate transport. Using a reconstituted pump in a membrane mimic environment, we show that MacAB-TolC from Escherichia coli couples substrate transport to ATP-hydrolysis with high efficiency. Contrary to the predictions of the currently prevailing "molecular bellows" model of MacB-operation, which assigns the power stroke to the ATP-binding by the nucleotide binding domains of the transporter, by utilizing a novel assay, we report clear synchronization of the substrate transfer with ATP-hydrolysis, suggesting that at least some of the power stroke for the substrate efflux is provided by ATP-hydrolysis. Our findings narrow down the window for energy consumption step that results in substrate transition into the TolC-channel, expanding the current understanding of the efflux cycle of the MacB-based tripartite assemblies. Based on that we propose a modified model of the MacB cycle within the context of tripartite complex assembly.
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Affiliation(s)
- Hager Souabni
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS UMR 7099, Université de Paris, Paris, France
- Fondation Edmond de Rothschild pour le développement de la recherche Scientifique, Institut de Biologie Physico-Chimique, Paris, France
| | - William Batista Dos Santos
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS UMR 7099, Université de Paris, Paris, France
- Fondation Edmond de Rothschild pour le développement de la recherche Scientifique, Institut de Biologie Physico-Chimique, Paris, France
| | - Quentin Cece
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS UMR 7099, Université de Paris, Paris, France
- Fondation Edmond de Rothschild pour le développement de la recherche Scientifique, Institut de Biologie Physico-Chimique, Paris, France
| | - Laurent J Catoire
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS UMR 7099, Université de Paris, Paris, France
- Fondation Edmond de Rothschild pour le développement de la recherche Scientifique, Institut de Biologie Physico-Chimique, Paris, France
| | - Dhenesh Puvanendran
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS UMR 7099, Université de Paris, Paris, France
- Fondation Edmond de Rothschild pour le développement de la recherche Scientifique, Institut de Biologie Physico-Chimique, Paris, France
- Department of Cell Biology, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY, USA
| | | | - Martin Picard
- Laboratoire de Biologie Physico-Chimique des Protéines Membranaires, CNRS UMR 7099, Université de Paris, Paris, France.
- Fondation Edmond de Rothschild pour le développement de la recherche Scientifique, Institut de Biologie Physico-Chimique, Paris, France.
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32
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Santoscoy MC, Jarboe LR. A systematic framework for using membrane metrics for strain engineering. Metab Eng 2021; 66:98-113. [PMID: 33813035 DOI: 10.1016/j.ymben.2021.03.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 03/14/2021] [Accepted: 03/15/2021] [Indexed: 11/20/2022]
Abstract
The cell membrane plays a central role in the fitness and performance of microbial cell factories and therefore it is an attractive engineering target. The goal of this work is to develop a systematic framework for identifying membrane features for use as engineering targets. The metrics that describe the composition of the membrane can be visualized as "knobs" that modulate various "outcomes", such as physical properties of the membrane and metabolic activity in the form of growth and productivity, with these relationships varying depending on the condition. We generated a set of strains with altered membrane lipid composition via expression of des, fabA and fabB and performed a rigorous characterization of these knobs and outcomes across several individual inhibitory conditions. Here, the knobs are the relative abundance of unsaturated lipids and lipids containing cyclic rings; the average lipid length, and the ratio of linear and non-linear lipids (L/nL ratio). The outcomes are membrane permeability, hydrophobicity, fluidity, and specific growth rate. This characterization identified significant correlations between knobs and outcomes that were specific to individual inhibitors, but also were significant across all tested conditions. For example, across all conditions, the L/nL ratio is positively correlated with the cell surface hydrophobicity, and the average lipid length is positively correlated with specific growth rate. A subsequent analysis of the data with the individual inhibitors identified pairs of lipid metrics and membrane properties that were predicted to impact cell growth in seven modeled scenarios with two or more inhibitors. The L/nL ratio and the membrane hydrophobicity were predicted to impact cell growth with the highest frequency. We experimentally validated this prediction in the combined condition of 42 °C, 2.5 mM furfural and 2% v/v ethanol in minimal media. Membrane hydrophobicity was confirmed to be a significant predictor of ethanol production. This work demonstrates that membrane physical properties can be used to predict the performance of biocatalysts in single and multiple inhibitory conditions, and possibly as an engineering target. In this manner, membrane properties can possibly be used as screening or selection metrics for library- or evolution-based strain engineering.
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Affiliation(s)
- Miguel C Santoscoy
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA
| | - Laura R Jarboe
- Department of Chemical and Biological Engineering, Iowa State University, Ames, IA, 50011, USA.
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33
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Tang X, Chang S, Zhang K, Luo Q, Zhang Z, Wang T, Qiao W, Wang C, Shen C, Zhang Z, Zhu X, Wei X, Dong C, Zhang X, Dong H. Structural basis for bacterial lipoprotein relocation by the transporter LolCDE. Nat Struct Mol Biol 2021; 28:347-355. [PMID: 33782615 DOI: 10.1038/s41594-021-00573-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Accepted: 02/17/2021] [Indexed: 02/05/2023]
Abstract
Lipoproteins in the outer membrane of Gram-negative bacteria are involved in various vital physiological activities, including multidrug resistance. Synthesized in the cytoplasm and matured in the inner membrane, lipoproteins must be transported to the outer membrane through the Lol pathway mediated by the ATP-binding cassette transporter LolCDE in the inner membrane via an unknown mechanism. Here, we report cryo-EM structures of Escherichia coli LolCDE in apo, lipoprotein-bound, LolA-bound, ADP-bound and AMP-PNP-bound states at a resolution of 3.2-3.8 Å, covering the complete lipoprotein transport cycle. Mutagenesis and in vivo viability assays verify features of the structures and reveal functional residues and structural characteristics of LolCDE. The results provide insights into the mechanisms of sorting and transport of outer-membrane lipoproteins and may guide the development of novel therapies against multidrug-resistant Gram-negative bacteria.
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Affiliation(s)
- Xiaodi Tang
- State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan, China
| | - Shenghai Chang
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University, School of Medicine, Hangzhou, Zhejiang, China.,Center of Cryo Electron Microscopy, Zhejiang University, Hangzhou, Zhejiang, China.,Zhejiang Laboratory for System and Precision Medicine, Zhejiang University Medical Center, Hangzhou, Zhejiang, China
| | - Ke Zhang
- State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan, China
| | - Qinghua Luo
- State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan, China
| | - Zhengyu Zhang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, School of Pharmaceutical Sciences, Wuhan University, Wuhan, Hubei, China
| | - Ting Wang
- State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan, China
| | - Wen Qiao
- State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan, China
| | - Chen Wang
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University, School of Medicine, Hangzhou, Zhejiang, China.,Center of Cryo Electron Microscopy, Zhejiang University, Hangzhou, Zhejiang, China.,Zhejiang Laboratory for System and Precision Medicine, Zhejiang University Medical Center, Hangzhou, Zhejiang, China
| | - Chongrong Shen
- State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan, China
| | - Zhibo Zhang
- State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan, China
| | - Xiaofeng Zhu
- State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan, China.,College of Life Science, Sichuan University, Chengdu, Sichuan, China
| | - Xiawei Wei
- State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan, China
| | - Changjiang Dong
- Biomedical Research Centre, Norwich Medical School, University of East Anglia, Norwich, UK.
| | - Xing Zhang
- Department of Biophysics and Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University, School of Medicine, Hangzhou, Zhejiang, China. .,Center of Cryo Electron Microscopy, Zhejiang University, Hangzhou, Zhejiang, China. .,Zhejiang Laboratory for System and Precision Medicine, Zhejiang University Medical Center, Hangzhou, Zhejiang, China.
| | - Haohao Dong
- State Key Laboratory of Biotherapy and Cancer Center, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, Sichuan, China.
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El Rayes J, Rodríguez-Alonso R, Collet JF. Lipoproteins in Gram-negative bacteria: new insights into their biogenesis, subcellular targeting and functional roles. Curr Opin Microbiol 2021; 61:25-34. [PMID: 33667939 DOI: 10.1016/j.mib.2021.02.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 02/06/2023]
Abstract
Bacterial lipoproteins are globular proteins anchored to a membrane by a lipid moiety. By discovering new functions carried out by lipoproteins, recent research has highlighted the crucial roles played by these proteins in the cell envelope of Gram-negative bacteria. Here, after discussing the wide range of activities carried out by lipoproteins in the model bacterium Escherichia coli, we review new insights into the essential mechanisms involved in lipoprotein maturation, sorting and targeting to their final destination. A special attention will also be given to the recent identification of lipoproteins on the surface of E. coli and of other bacteria. The renewed interest in lipoproteins is driven by the need to identify novel targets for antibiotic development.
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Affiliation(s)
- Jessica El Rayes
- WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium; de Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75, 1200 Brussels, Belgium
| | - Raquel Rodríguez-Alonso
- WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium; de Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75, 1200 Brussels, Belgium
| | - Jean-François Collet
- WELBIO, Avenue Hippocrate 75, 1200 Brussels, Belgium; de Duve Institute, Université catholique de Louvain, Avenue Hippocrate 75, 1200 Brussels, Belgium.
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Colistin Dependence in Extensively Drug-Resistant Acinetobacter baumannii Strain Is Associated with IS Ajo2 and IS Aba13 Insertions and Multiple Cellular Responses. Int J Mol Sci 2021; 22:ijms22020576. [PMID: 33430070 PMCID: PMC7827689 DOI: 10.3390/ijms22020576] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 02/06/2023] Open
Abstract
The nosocomial opportunistic Gram-negative bacterial pathogen Acinetobacter baumannii is resistant to multiple antimicrobial agents and an emerging global health problem. The polymyxin antibiotic colistin, targeting the negatively charged lipid A component of the lipopolysaccharide on the bacterial cell surface, is often considered as the last-resort treatment, but resistance to colistin is unfortunately increasing worldwide. Notably, colistin-susceptible A. baumannii can also develop a colistin dependence after exposure to this drug in vitro. Colistin dependence might represent a stepping stone to resistance also in vivo. However, the mechanisms are far from clear. To address this issue, we combined proteogenomics, high-resolution microscopy, and lipid profiling to characterize and compare A. baumannii colistin-susceptible clinical isolate (Ab-S) of to its colistin-dependent subpopulation (Ab-D) obtained after subsequent passages in moderate colistin concentrations. Incidentally, in the colistin-dependent subpopulation the lpxA gene was disrupted by insertion of ISAjo2, the lipid A biosynthesis terminated, and Ab-D cells displayed a lipooligosaccharide (LOS)-deficient phenotype. Moreover, both mlaD and pldA genes were perturbed by insertions of ISAjo2 and ISAba13, and LOS-deficient bacteria displayed a capsule with decreased thickness as well as other surface imperfections. The major changes in relative protein abundance levels were detected in type 6 secretion system (T6SS) components, the resistance-nodulation-division (RND)-type efflux pumps, and in proteins involved in maintenance of outer membrane asymmetry. These findings suggest that colistin dependence in A. baumannii involves an ensemble of mechanisms seen in resistance development and accompanied by complex cellular events related to insertional sequences (ISs)-triggered LOS-deficiency. To our knowledge, this is the first study demonstrating the involvement of ISAjo2 and ISAba13 IS elements in the modulation of the lipid A biosynthesis and associated development of dependence on colistin.
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Cole GB, Bateman TJ, Moraes TF. The surface lipoproteins of gram-negative bacteria: Protectors and foragers in harsh environments. J Biol Chem 2021; 296:100147. [PMID: 33277359 PMCID: PMC7857515 DOI: 10.1074/jbc.rev120.008745] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 12/02/2020] [Accepted: 12/04/2020] [Indexed: 11/06/2022] Open
Abstract
Gram-negative pathogens are enveloped by an outer membrane that serves as a double-edged sword: On the one hand, it provides a layer of protection for the bacterium from environmental insults, including other bacteria and the host immune system. On the other hand, it restricts movement of vital nutrients into the cell and provides a plethora of antigens that can be detected by host immune systems. One strategy used to overcome these limitations is the decoration of the outer surface of gram-negative bacteria with proteins tethered to the outer membrane through a lipid anchor. These surface lipoproteins (SLPs) fulfill critical roles in immune evasion and nutrient acquisition, but as more bacterial genomes are sequenced, we are beginning to discover their prevalence and their different roles and mechanisms and importantly how we can exploit them as antimicrobial targets. This review will focus on representative SLPs that gram-negative bacteria use to overcome host innate immunity, specifically the areas of nutritional immunity and complement system evasion. We elaborate on the structures of some notable SLPs required for binding target molecules in hosts and how this information can be used alongside bioinformatics to understand mechanisms of binding and in the discovery of new SLPs. This information provides a foundation for the development of therapeutics and the design of vaccine antigens.
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Affiliation(s)
- Gregory B Cole
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Thomas J Bateman
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Trevor F Moraes
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada.
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37
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Mozaheb N, Mingeot-Leclercq MP. Membrane Vesicle Production as a Bacterial Defense Against Stress. Front Microbiol 2020; 11:600221. [PMID: 33362747 PMCID: PMC7755613 DOI: 10.3389/fmicb.2020.600221] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/16/2020] [Indexed: 12/15/2022] Open
Abstract
Membrane vesicles are the nano-sized vesicles originating from membranes. The production of membrane vesicles is a common feature among bacteria. Depending on the bacterial growth phase and environmental conditions, membrane vesicles show diverse characteristics. Various physiological and ecological roles have been attributed to membrane vesicles under both homeostatic and stressful conditions. Pathogens encounter several stressors during colonization in the hostile environment of host tissues. Nutrient deficiency, the presence of antibiotics as well as elements of the host’s immune system are examples of stressors threatening pathogens inside their host. To combat stressors and survive, pathogens have established various defensive mechanisms, one of them is production of membrane vesicles. Pathogens produce membrane vesicles to alleviate the destructive effects of antibiotics or other types of antibacterial treatments. Additionally, membrane vesicles can also provide benefits for the wider bacterial community during infections, through the transfer of resistance or virulence factors. Hence, given that membrane vesicle production may affect the activities of antibacterial agents, their production should be considered when administering antibacterial treatments. Besides, regarding that membrane vesicles play vital roles in bacteria, disrupting their production may suggest an alternative strategy for battling against pathogens. Here, we aim to review the stressors encountered by pathogens and shed light on the roles of membrane vesicles in increasing pathogen adaptabilities in the presence of stress-inducing factors.
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Affiliation(s)
- Negar Mozaheb
- Université catholique de Louvain (UCL), Louvain Drug Research Institute (LDRI), Cellular & Molecular Pharmacology Unit (FACM), Brussels, Belgium
| | - Marie-Paule Mingeot-Leclercq
- Université catholique de Louvain (UCL), Louvain Drug Research Institute (LDRI), Cellular & Molecular Pharmacology Unit (FACM), Brussels, Belgium
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38
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Mokrzan EM, Ahearn CP, Buzzo JR, Novotny LA, Zhang Y, Goodman SD, Bakaletz LO. Nontypeable Haemophilus influenzae newly released (NRel) from biofilms by antibody-mediated dispersal versus antibody-mediated disruption are phenotypically distinct. Biofilm 2020; 2:100039. [PMID: 33447823 PMCID: PMC7798465 DOI: 10.1016/j.bioflm.2020.100039] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 11/02/2020] [Accepted: 11/12/2020] [Indexed: 02/08/2023] Open
Abstract
Biofilms contribute significantly to the chronicity and recurrence of bacterial diseases due to the fact that biofilm-resident bacteria are highly recalcitrant to killing by host immune effectors and antibiotics. Thus, antibody-mediated release of bacteria from biofilm residence into the surrounding milieu supports a powerful strategy to resolve otherwise difficult-to-treat biofilm-associated diseases. In our prior work, we revealed that antibodies directed against two unique determinants of nontypeable Haemophilus influenzae (NTHI) [e.g. the Type IV pilus (T4P) or a bacterial DNABII DNA-binding protein, a species-independent target that provides structural integrity to bacterial biofilms] release biofilm-resident bacteria via discrete mechanisms. Herein, we now show that the phenotype of the resultant newly released (or NRel) NTHI is dependent upon the specific mechanism of release. We used flow cytometry, proteomic profiles, and targeted transcriptomics to demonstrate that the two NRel populations were significantly different not only from planktonically grown NTHI, but importantly, from each other despite genetic identity. Moreover, each NRel population had a distinct, significantly increased susceptibility to killing by either a sulfonamide or β-lactam antibiotic compared to planktonic NTHI, an observation consistent with their individual proteomes and further supported by relative differences in targeted gene expression. The distinct phenotypes of NTHI released from biofilms by antibodies directed against specific epitopes of T4P or DNABII binding proteins provide new opportunities to develop targeted therapeutic strategies for biofilm eradication and disease resolution.
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Affiliation(s)
- Elaine M Mokrzan
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Christian P Ahearn
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - John R Buzzo
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Laura A Novotny
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Yan Zhang
- Department of Biomedical Informatics, The Ohio State University College of Medicine, Columbus, OH, USA.,The Ohio State University Comprehensive Cancer Center (OSUCCC - James), Columbus, OH, USA
| | - Steven D Goodman
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Lauren O Bakaletz
- Center for Microbial Pathogenesis, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
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Insights into bacterial cell division from a structure of EnvC bound to the FtsX periplasmic domain. Proc Natl Acad Sci U S A 2020; 117:28355-28365. [PMID: 33097670 PMCID: PMC7668044 DOI: 10.1073/pnas.2017134117] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The peptidoglycan layer is a core component of the bacterial cell envelope that provides a barrier to the environment and protection from osmotic shock. During division, bacteria must break and rebuild the peptidoglycan layer to enable separation of daughter cells. In E. coli, two of the three amidases responsible (AmiA and AmiB) are regulated by a single periplasmic activator (EnvC) that is, itself, controlled by an atypical ABC transporter (FtsEX) tethered to the cytoplasmic septal Z-ring. Here we define the structural basis for the interaction of FtsEX with EnvC and suggest a molecular mechanism for amidase activation where EnvC autoinhibition is relieved by ATP-driven conformational changes transmitted through the FtsEX-EnvC complex. FtsEX is a bacterial ABC transporter that regulates the activity of periplasmic peptidoglycan amidases via its interaction with the murein hydrolase activator, EnvC. In Escherichia coli, FtsEX is required to separate daughter cells after cell division and for viability in low-osmolarity media. Both the ATPase activity of FtsEX and its periplasmic interaction with EnvC are required for amidase activation, but the process itself is poorly understood. Here we present the 2.1 Å structure of the FtsX periplasmic domain in complex with its periplasmic partner, EnvC. The EnvC-FtsX periplasmic domain complex has a 1-to-2 stoichiometry with two distinct FtsX-binding sites located within an antiparallel coiled coil domain of EnvC. Residues involved in amidase activation map to a previously identified groove in the EnvC LytM domain that is here found to be occluded by a “restraining arm” suggesting a self-inhibition mechanism. Mutational analysis, combined with bacterial two-hybrid screens and in vivo functional assays, verifies the FtsEX residues required for EnvC binding and experimentally test a proposed mechanism for amidase activation. We also define a predicted link between FtsEX and integrity of the outer membrane. Both the ATPase activity of FtsEX and its periplasmic interaction with EnvC are required for resistance to membrane-attacking antibiotics and detergents to which E. coli would usually be considered intrinsically resistant. These structural and functional data provide compelling mechanistic insight into FtsEX-mediated regulation of EnvC and its downstream control of periplasmic peptidoglycan amidases.
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40
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Belmont-Monroy L, Saitz-Rojas W, Soria-Bustos J, Mickey AS, Sherman NE, Orsburn BC, Ruiz-Perez F, Santiago AE. Characterization of a novel AraC/XylS-regulated family of N-acyltransferases in pathogens of the order Enterobacterales. PLoS Pathog 2020; 16:e1008776. [PMID: 32845938 PMCID: PMC7478709 DOI: 10.1371/journal.ppat.1008776] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 09/08/2020] [Accepted: 07/04/2020] [Indexed: 11/18/2022] Open
Abstract
Enteroaggregative Escherichia coli (EAEC) is a diarrheagenic pathotype associated with traveler’s diarrhea, foodborne outbreaks and sporadic diarrhea in industrialized and developing countries. Regulation of virulence in EAEC is mediated by AggR and its negative regulator Aar. Together, they control the expression of at least 210 genes. On the other hand, we observed that about one third of Aar-regulated genes are related to metabolism and transport. In this study we show the AggR/Aar duo controls the metabolism of lipids. Accordingly, we show that AatD, encoded in the AggR-regulated aat operon (aatPABCD) is an N-acyltransferase structurally similar to the essential Apolipoprotein N-acyltransferase Lnt and is required for the acylation of Aap (anti-aggregation protein). Deletion of aatD impairs post-translational modification of Aap and causes its accumulation in the bacterial periplasm. trans-complementation of 042aatD mutant with the AatD homolog of ETEC or with the N-acyltransferase Lnt reestablished translocation of Aap. Site-directed mutagenesis of the E207 residue in the putative acyltransferase catalytic triad disrupted the activity of AatD and caused accumulation of Aap in the periplasm due to reduced translocation of Aap at the bacterial surface. Furthermore, Mass spectroscopy revealed that Aap is acylated in a putative lipobox at the N-terminal of the mature protein, implying that Aap is a lipoprotein. Lastly, deletion of aatD impairs bacterial colonization of the streptomycin-treated mouse model. Our findings unveiled a novel N-acyltransferase family associated with bacterial virulence, and that is tightly regulated by AraC/XylS regulators in the order Enterobacterales. Although the regulatory scheme of AggR is well understood, the biological relevance of half of AggR-regulated proteins remains unknown. In this study we provide experimental evidence that the AggR-regulated AatD is a novel N-acyltransferase restricted to pathogens of the order Enterobacterales, including EAEC, ETEC, Yersinia sp., and C. rodentium. AatD is structurally similar to Lnt. However, unlike Lnt which is essential for cellular functions, AatD is a dedicated N-acyltransferase required for post-translational modification of virulence factors. Aap was identified as a lipoprotein acylated by AatD. Lipid modification in Aap provides an important post-translational mechanism to regulate the trafficking, stability and subcellular localization of Aap. In the absence of AatD, Aap is retained in the periplasmic space and cannot be translocated to the bacterial surface, presumably, restricting the biological function of the protein. Our data suggest that AggR and Aar virulence regulators, not only regulate the expression of Aap virulence factor at the transcriptional level, but also regulate translocation of Aap to the bacterial surface, which is required for full virulence of EAEC, unveiling an important mechanism of virulence regulation.
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Affiliation(s)
- Laura Belmont-Monroy
- Department of Pediatrics, University of Virginia School of Medicine and University of Virginia Children’s Hospital, Charlottesville, Virginia, United States of America
- Department of Public Health, UNAM School of Medicine and Federico Gomez Children’s Hospital, Mexico City, Mexico
| | - Waleska Saitz-Rojas
- Department of Pediatrics, University of Virginia School of Medicine and University of Virginia Children’s Hospital, Charlottesville, Virginia, United States of America
| | - Jorge Soria-Bustos
- Department of Pediatrics, University of Virginia School of Medicine and University of Virginia Children’s Hospital, Charlottesville, Virginia, United States of America
| | - Abigail S. Mickey
- Department of Pediatrics, University of Virginia School of Medicine and University of Virginia Children’s Hospital, Charlottesville, Virginia, United States of America
| | - Nicholas E. Sherman
- W. M. Keck Biomedical Mass Spectrometry Lab. University of Virginia, Charlottesville, Virginia, United States of America
| | - Benjamin C. Orsburn
- W. M. Keck Biomedical Mass Spectrometry Lab. University of Virginia, Charlottesville, Virginia, United States of America
| | - Fernando Ruiz-Perez
- Department of Pediatrics, University of Virginia School of Medicine and University of Virginia Children’s Hospital, Charlottesville, Virginia, United States of America
| | - Araceli E. Santiago
- Department of Pediatrics, University of Virginia School of Medicine and University of Virginia Children’s Hospital, Charlottesville, Virginia, United States of America
- * E-mail: .
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41
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Roles of ATP Hydrolysis by FtsEX and Interaction with FtsA in Regulation of Septal Peptidoglycan Synthesis and Hydrolysis. mBio 2020; 11:mBio.01247-20. [PMID: 32636250 PMCID: PMC7343993 DOI: 10.1128/mbio.01247-20] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
In Escherichia coli, FtsEX coordinates peptidoglycan (PG) synthesis and hydrolysis at the septum. It acts on FtsA in the cytoplasm to promote recruitment of septal PG synthetases and recruits EnvC, an activator of septal PG hydrolases, in the periplasm. Following recruitment, ATP hydrolysis by FtsEX is thought to regulate both PG synthesis and hydrolysis, but how it does this is not well understood. Here, we show that an ATPase mutant of FtsEX blocks septal PG synthesis similarly to cephalexin, suggesting that ATP hydrolysis by FtsEX is required throughout septation. Using mutants that uncouple the roles of FtsEX in septal PG synthesis and hydrolysis, we find that recruitment of EnvC to the septum by FtsEX, but not ATP hydrolysis, is required to promote cell separation when the NlpD-mediated cell separation system is present. However, ATP hydrolysis by FtsEX becomes necessary for efficient cell separation when the NlpD system is inactivated, suggesting that the ATPase activity of FtsEX is required for optimal activity of EnvC. Importantly, under conditions that suppress the role of FtsEX in cell division, disruption of the FtsEX-FtsA interaction delays cell separation, highlighting the importance of this interaction in coupling the cell separation system with the septal PG synthetic complex.IMPORTANCE Cytokinesis in Gram-negative bacteria requires coordinated invagination of the three layers of the cell envelope; otherwise, cells become sensitive to hydrophobic antibiotics and can even undergo cell lysis. In E. coli, the ABC transporter FtsEX couples the synthesis and hydrolysis of the stress-bearing peptidoglycan layer at the septum by interacting with FtsA and EnvC, respectively. ATP hydrolysis by FtsEX is critical for its function, but the reason why is not clear. Here, we find that in the absence of ATP hydrolysis, FtsEX blocks septal PG synthesis similarly to cephalexin. However, an FtsEX ATPase mutant, under conditions where it cannot block division, rescues ftsEX phenotypes as long as a partially redundant cell separation system is present. Furthermore, we find that the FtsEX-FtsA interaction is important for efficient cell separation.
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42
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Knoke LR, Abad Herrera S, Götz K, Justesen BH, Günther Pomorski T, Fritz C, Schäkermann S, Bandow JE, Aktas M. Agrobacterium tumefaciens Small Lipoprotein Atu8019 Is Involved in Selective Outer Membrane Vesicle (OMV) Docking to Bacterial Cells. Front Microbiol 2020; 11:1228. [PMID: 32582124 PMCID: PMC7296081 DOI: 10.3389/fmicb.2020.01228] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 05/14/2020] [Indexed: 12/02/2022] Open
Abstract
Outer membrane vesicles (OMVs), released from Gram-negative bacteria, have been attributed to intra- and interspecies communication and pathogenicity in diverse bacteria. OMVs carry various components including genetic material, toxins, signaling molecules, or proteins. Although the molecular mechanism(s) of cargo delivery is not fully understood, recent studies showed that transfer of the OMV content to surrounding cells is mediated by selective interactions. Here, we show that the phytopathogen Agrobacterium tumefaciens, the causative agent of crown gall disease, releases OMVs, which attach to the cell surface of various Gram-negative bacteria. The OMVs contain the conserved small lipoprotein Atu8019. An atu8019-deletion mutant produced wildtype-like amounts of OMVs with a subtle but reproducible reduction in cell-attachment. Otherwise, loss of atu8019 did not alter growth, susceptibility against cations or antibiotics, attachment to plant cells, virulence, motility, or biofilm formation. In contrast, overproduction of Atu8019 in A. tumefaciens triggered cell aggregation and biofilm formation. Localization studies revealed that Atu8019 is surface exposed in Agrobacterium cells and in OMVs supporting a role in cell adhesion. Purified Atu8019 protein reconstituted into liposomes interacted with model membranes and with the surface of several Gram-negative bacteria. Collectively, our data suggest that the small lipoprotein Atu8019 is involved in OMV docking to specific bacteria.
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Affiliation(s)
- Lisa Roxanne Knoke
- Faculty of Biology and Biotechnology, Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Sara Abad Herrera
- Faculty of Chemistry and Biochemistry, Department of Molecular Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Katrin Götz
- Faculty of Biology and Biotechnology, Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Bo Højen Justesen
- Faculty of Chemistry and Biochemistry, Department of Molecular Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Thomas Günther Pomorski
- Faculty of Chemistry and Biochemistry, Department of Molecular Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Christiane Fritz
- Faculty of Biology and Biotechnology, Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Sina Schäkermann
- Faculty of Biology and Biotechnology, Department of Applied Microbiology, Ruhr University Bochum, Bochum, Germany
| | - Julia Elisabeth Bandow
- Faculty of Biology and Biotechnology, Department of Applied Microbiology, Ruhr University Bochum, Bochum, Germany
| | - Meriyem Aktas
- Faculty of Biology and Biotechnology, Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
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43
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Rao S, Bates GT, Matthews CR, Newport TD, Vickery ON, Stansfeld PJ. Characterizing Membrane Association and Periplasmic Transfer of Bacterial Lipoproteins through Molecular Dynamics Simulations. Structure 2020; 28:475-487.e3. [PMID: 32053772 PMCID: PMC7139219 DOI: 10.1016/j.str.2020.01.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 11/22/2019] [Accepted: 01/24/2020] [Indexed: 01/09/2023]
Abstract
Escherichia coli lipoprotein precursors at the inner membrane undergo three maturation stages before transport by the Lol system to the outer membrane. Here, we develop a pipeline to simulate the membrane association of bacterial lipoproteins in their four maturation states. This has enabled us to model and simulate 81 of the predicted 114 E. coli lipoproteins and reveal their interactions with the host lipid membrane. As part of this set we characterize the membrane contacts of LolB, the lipoprotein involved in periplasmic translocation. We also consider the means and bioenergetics for lipoprotein localization. Our calculations uncover a preference for LolB over LolA and therefore indicate how a lipoprotein may be favorably transferred from the inner to outer membrane. Finally, we reveal that LolC has a role in membrane destabilization, thereby promoting lipoprotein transfer to LolA.
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Affiliation(s)
- Shanlin Rao
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - George T Bates
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Callum R Matthews
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Thomas D Newport
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK
| | - Owen N Vickery
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK; School of Life Sciences & Department of Chemistry, University of Warwick, Gibbet Hill Campus, Coventry CV4 7AL, UK
| | - Phillip J Stansfeld
- Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK; School of Life Sciences & Department of Chemistry, University of Warwick, Gibbet Hill Campus, Coventry CV4 7AL, UK.
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Abstract
Lipoproteins are produced by both Gram-positive and Gram-negative bacteria. Once secreted, lipoproteins are quickly acylated, anchoring them into the plasma membrane. Recent work has shown that Gram-positive bacteria are able to generate considerable diversity in the acylation of their lipoproteins, though the mechanisms involved are only just beginning to emerge. In Gram-negative organisms, most lipoproteins are subsequently trafficked to the outer membrane (OM). Lipoprotein trafficking is an essential pathway in these bacteria. At least one OM lipoprotein component is required by each of the essential machines that assemble the OM (such as the Bam and Lpt machines) and build the peptidoglycan cell wall (Lpo-penicillin-binding protein complexes). The Lol pathway has been the paradigm for OM lipoprotein trafficking: a complex of LolCDE extracts lipoproteins from the plasma membrane, LolA shuttles them through the periplasmic space, and LolB anchors them into the OM. The peptide signals responsible for OM-targeting via LolCDE have long been known for Escherichia coli. Remarkably, production of novel lipoprotein acyl forms in E. coli has reinforced the idea that lipid signals also contribute to OM targeting via LolCDE. Moreover, recent work has shown that lipoprotein trafficking can occur in E. coli without either LolA or LolB. Therefore, current evidence suggests that at least one additional, LolAB-independent route for OM lipoprotein trafficking exists. This chapter reviews the posttranslocation modifications of all lipoproteins, with a focus on the trafficking of lipoproteins to the OM of Gram-negative bacteria.
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Lorenz C, Dougherty TJ, Lory S. Correct Sorting of Lipoproteins into the Inner and Outer Membranes of Pseudomonas aeruginosa by the Escherichia coli LolCDE Transport System. mBio 2019; 10:e00194-19. [PMID: 30992347 PMCID: PMC6469965 DOI: 10.1128/mbio.00194-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 03/12/2019] [Indexed: 12/13/2022] Open
Abstract
Biogenesis of the outer membrane of Gram-negative bacteria depends on dedicated macromolecular transport systems. The LolABCDE proteins make up the machinery for lipoprotein trafficking from the inner membrane (IM) across the periplasm to the outer membrane (OM). The Lol apparatus is additionally responsible for differentiating OM lipoproteins from those for the IM. In Enterobacteriaceae, a default sorting mechanism has been proposed whereby an aspartic acid at position +2 of the mature lipoproteins prevents Lol recognition and leads to their IM retention. In other bacteria, the conservation of sequences immediately following the acylated cysteine is variable. Here we show that in Pseudomonas aeruginosa, the three essential Lol proteins (LolCDE) can be replaced with those from Escherichia coli The P. aeruginosa lipoproteins MexA, OprM, PscJ, and FlgH, with different sequences at their N termini, were correctly sorted by either the E. coli or P. aeruginosa LolCDE. We further demonstrate that an inhibitor of E. coli LolCDE is active against P. aeruginosa only when expressing the E. coli orthologues. Our work shows that Lol proteins recognize a wide range of signals, consisting of an acylated cysteine and a specific conformation of the adjacent domain, determining IM retention or transport to the OM.IMPORTANCE Gram-negative bacteria build their outer membranes (OM) from components that are initially located in the inner membrane (IM). A fraction of lipoproteins is transferred to the OM by the transport machinery consisting of LolABCDE proteins. Our work demonstrates that the LolCDE complexes of the transport pathways of Escherichia coli and Pseudomonas aeruginosa are interchangeable, with the E. coli orthologues correctly sorting the P. aeruginosa lipoproteins while retaining their sensitivity to a small-molecule inhibitor. These findings question the nature of IM retention signals, identified in E. coli as aspartate at position +2 of mature lipoproteins. We propose an alternative model for the sorting of IM and OM lipoproteins based on their relative affinities for the IM and the ability of the promiscuous sorting machinery to deliver lipoproteins to their functional sites in the OM.
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Affiliation(s)
- Christian Lorenz
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Thomas J Dougherty
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Stephen Lory
- Department of Microbiology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, USA
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