1
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Rooney J, Rivera-de-Torre E, Li R, Mclean K, Price DR, Nisbet AJ, Laustsen AH, Jenkins TP, Hofmann A, Bakshi S, Zarkan A, Cantacessi C. Structural and functional analyses of nematode-derived antimicrobial peptides support the occurrence of direct mechanisms of worm-microbiota interactions. Comput Struct Biotechnol J 2024; 23:1522-1533. [PMID: 38633385 PMCID: PMC11021794 DOI: 10.1016/j.csbj.2024.04.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Revised: 04/07/2024] [Accepted: 04/09/2024] [Indexed: 04/19/2024] Open
Abstract
The complex relationships between gastrointestinal (GI) nematodes and the host gut microbiota have been implicated in key aspects of helminth disease and infection outcomes. Nevertheless, the direct and indirect mechanisms governing these interactions are, thus far, largely unknown. In this proof-of-concept study, we demonstrate that the excretory-secretory products (ESPs) and extracellular vesicles (EVs) of key GI nematodes contain peptides that, when recombinantly expressed, exert antimicrobial activity in vitro against Bacillus subtilis. In particular, using time-lapse microfluidics microscopy, we demonstrate that exposure of B. subtilis to a recombinant saposin-domain containing peptide from the 'brown stomach worm', Teladorsagia circumcincta, and a metridin-like ShK toxin from the 'barber's pole worm', Haemonchus contortus, results in cell lysis and significantly reduced growth rates. Data from this study support the hypothesis that GI nematodes may modulate the composition of the vertebrate gut microbiota directly via the secretion of antimicrobial peptides, and pave the way for future investigations aimed at deciphering the impact of such changes on the pathophysiology of GI helminth infection and disease.
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Affiliation(s)
- James Rooney
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | | | - Ruizhe Li
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Kevin Mclean
- Moredun Research Institute, Penicuik Midlothian, United Kingdom
| | | | | | - Andreas H. Laustsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Timothy P. Jenkins
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Andreas Hofmann
- Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Kulmbach, Germany
- Melbourne Veterinary School, Faculty of Science, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Somenath Bakshi
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Ashraf Zarkan
- Department of Genetics, University of Cambridge, Cambridge, United Kingdom
| | - Cinzia Cantacessi
- Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
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2
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Xue Y, Li H, Kang X. Molecular unraveling of polysaccharide digestion in wood-feeding termites: A solid-state NMR perspective. Carbohydr Polym 2024; 331:121843. [PMID: 38388031 DOI: 10.1016/j.carbpol.2024.121843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 01/08/2024] [Accepted: 01/18/2024] [Indexed: 02/24/2024]
Abstract
Termites are among the most efficient organisms utilizing polysaccharides from wood and play a significant role in global carbon recycling, especially within tropical and subtropical ecosystems. Yet, the molecular details in polysaccharide degradation by termites remain largely unexplored. In this work, we have elucidated the shared and distinct molecular details in polysaccharides digestion by the higher termite Nasutitermes on poplar and the lower termite Cryptotermes on pine using high resolution solid-state nuclear magnetic resonance spectroscopy. For the first time, structural polymers are partitioned into the minor mobile and dominant rigid phases for individual examination. The mobile polysaccharides receive less structural impacts and exhibit greater digestibility compared to the rigid counterparts. While both termites effectively degrade cellulose, Nasutitermes significantly outperforms Cryptotermes in hemicellulose breakdown. In the rigid phase, cellulose is comprehensively degraded into a fragmented and more dynamically consistent structure; As Nasutitermes breaks down hemicellulose in a similar manner to cellulose, Cryptotermes selectively digests hemicellulose at its interfaces with cellulose. Additionally, crystalline cellulose undergoes selective degradation, and the digestion of amorphous cellulose might involve sugar chain detachment within microfibrils. Overall, our findings offer significant advancements and fresh perspectives on the polysaccharide digestion strategies of different termite lineages.
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Affiliation(s)
- Yi Xue
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China
| | - Hongjie Li
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Key Laboratory of Biotechnology in Plant Protection of MARA and Zhejiang Province, Institute of Plant Virology, Ningbo University, Ningbo 315211, China.
| | - Xue Kang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, China.
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3
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Xue Y, Yu C, Ouyang H, Huang J, Kang X. Uncovering the Molecular Composition and Architecture of the Bacillus subtilis Biofilm via Solid-State NMR Spectroscopy. J Am Chem Soc 2024; 146:11906-11923. [PMID: 38629727 DOI: 10.1021/jacs.4c00889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
The complex and dynamic compositions of biofilms, along with their sophisticated structural assembly mechanisms, endow them with exceptional capabilities to thrive in diverse conditions that are typically unfavorable for individual cells. Characterizing biofilms in their native state is significantly challenging due to their intrinsic complexities and the limited availability of noninvasive techniques. Here, we utilized solid-state nuclear magnetic resonance (NMR) spectroscopy to analyze Bacillus subtilis biofilms in-depth. Our data uncover a dynamically distinct organization within the biofilm: a dominant, hydrophilic, and mobile framework interspersed with minor, rigid cores of limited water accessibility. In these heterogeneous rigid cores, the major components are largely self-assembled. TasA fibers, the most robust elements, further provide a degree of mechanical support for the cell aggregates and some lipid vesicles. Notably, rigid cell aggregates can persist even without the major extracellular polymeric substance (EPS) polymers, although this leads to slight variations in their rigidity and water accessibility. Exopolysaccharides are exclusively present in the mobile domain, playing a pivotal role in its water retention property. Specifically, all water molecules are tightly bound within the biofilm matrix. These findings reveal a dual-layered defensive strategy within the biofilm: a diffusion barrier through limited water mobility in the mobile phase and a physical barrier posed by limited water accessibility in the rigid phase. Complementing these discoveries, our comprehensive, in situ compositional analysis is not only essential for delineating the sophisticated biofilm architecture but also reveals the presence of alternative genetic mechanisms for synthesizing exopolysaccharides beyond the known pathway.
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Affiliation(s)
- Yi Xue
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Chenjie Yu
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Han Ouyang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Jiaofang Huang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xue Kang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo, Zhejiang 315211, China
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4
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Kanaparthi D, Lampe M, Krohn JH, Zhu B, Klingl A, Lueders T. The reproduction of gram-negative protoplasts and the influence of environmental conditions on this process. iScience 2023; 26:108149. [PMID: 37942012 PMCID: PMC10628739 DOI: 10.1016/j.isci.2023.108149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/31/2023] [Accepted: 10/02/2023] [Indexed: 11/10/2023] Open
Abstract
Bacterial protoplasts are known to reproduce independently of canonical molecular biological processes. Although their reproduction is thought to be influenced by environmental conditions, the growth of protoplasts in their natural habitat has never been empirically studied. Here, we studied the life cycle of protoplasts in their native environment. Contrary to the previous perception that protoplasts reproduce in an erratic manner, cells in our study reproduced in a defined sequence of steps, always leading to viable daughter cells. Their reproduction can be explained by an interplay between intracellular metabolism, the physicochemical properties of cell constituents, and the nature of cations in the growth media. The efficiency of reproduction is determined by the environmental conditions. Under favorable environmental conditions, protoplasts reproduce with nearly similar efficiency to cells that possess a cell wall. In short, here we demonstrate the simplest method of cellular reproduction and the influence of environmental conditions on this process.
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Affiliation(s)
- Dheeraj Kanaparthi
- Max-Planck Institute for Biochemistry, Munich, Germany
- Chair of Ecological Microbiology, BayCeer, University of Bayreuth, Bayreuth, Germany
- Excellence Cluster ORIGINS, Garching, Germany
| | - Marko Lampe
- Advanced Light Microscopy Facility, European Molecular Biology Laboratory, Heidelberg, Germany
| | - Jan-Hagen Krohn
- Max-Planck Institute for Biochemistry, Munich, Germany
- Excellence Cluster ORIGINS, Garching, Germany
| | - Baoli Zhu
- Chair of Ecological Microbiology, BayCeer, University of Bayreuth, Bayreuth, Germany
- Key Laboratory of Agro-ecological Processes in Subtropical Regions, CAS, Changsha, China
| | - Andreas Klingl
- Department of Biology, LMU, Planegg-Martinsried, Germany
| | - Tillmann Lueders
- Chair of Ecological Microbiology, BayCeer, University of Bayreuth, Bayreuth, Germany
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5
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Wilson SA, Tank RKJ, Hobbs JK, Foster SJ, Garner EC. An exhaustive multiple knockout approach to understanding cell wall hydrolase function in Bacillus subtilis. mBio 2023; 14:e0176023. [PMID: 37768080 PMCID: PMC10653849 DOI: 10.1128/mbio.01760-23] [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: 07/12/2023] [Accepted: 08/03/2023] [Indexed: 09/29/2023] Open
Abstract
IMPORTANCE In order to grow, bacterial cells must both create and break down their cell wall. The enzymes that are responsible for these processes are the target of some of our best antibiotics. Our understanding of the proteins that break down the wall- cell wall hydrolases-has been limited by redundancy among the large number of hydrolases many bacteria contain. To solve this problem, we identified 42 cell wall hydrolases in Bacillus subtilis and created a strain lacking 40 of them. We show that cells can survive using only a single cell wall hydrolase; this means that to understand the growth of B. subtilis in standard laboratory conditions, it is only necessary to study a very limited number of proteins, simplifying the problem substantially. We additionally show that the ∆40 strain is a research tool to characterize hydrolases, using it to identify three "helper" hydrolases that act in certain stress conditions.
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Affiliation(s)
- Sean A. Wilson
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Center for Systems Biology, Harvard University, Cambridge, Massachusetts, USA
| | - Raveen K. J. Tank
- Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom
| | - Jamie K. Hobbs
- Department of Physics and Astronomy, University of Sheffield, Sheffield, United Kingdom
| | - Simon J. Foster
- School of Biosciences, University of Sheffield, Sheffield, United Kingdom
| | - Ethan C. Garner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA
- Center for Systems Biology, Harvard University, Cambridge, Massachusetts, USA
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6
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Razew A, Laguri C, Vallet A, Bougault C, Kaus-Drobek M, Sabala I, Simorre JP. Staphylococcus aureus sacculus mediates activities of M23 hydrolases. Nat Commun 2023; 14:6706. [PMID: 37872144 PMCID: PMC10593780 DOI: 10.1038/s41467-023-42506-w] [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: 04/13/2023] [Accepted: 10/12/2023] [Indexed: 10/25/2023] Open
Abstract
Peptidoglycan, a gigadalton polymer, functions as the scaffold for bacterial cell walls and provides cell integrity. Peptidoglycan is remodelled by a large and diverse group of peptidoglycan hydrolases, which control bacterial cell growth and division. Over the years, many studies have focused on these enzymes, but knowledge on their action within peptidoglycan mesh from a molecular basis is scarce. Here, we provide structural insights into the interaction between short peptidoglycan fragments and the entire sacculus with two evolutionarily related peptidases of the M23 family, lysostaphin and LytM. Through nuclear magnetic resonance, mass spectrometry, information-driven modelling, site-directed mutagenesis and biochemical approaches, we propose a model in which peptidoglycan cross-linking affects the activity, selectivity and specificity of these two structurally related enzymes differently.
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Affiliation(s)
- Alicja Razew
- Universite Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 avenue des Martyrs-CS10090, Grenoble cedex 9, 38044, France
- International Institute of Molecular and Cell Biology in Warsaw, 4 Ks. Trojdena Street, 02-109, Warsaw, Poland
- Laboratory of Protein Engineering, Mossakowski Medical Research Institute, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106, Warsaw, Poland
| | - Cedric Laguri
- Universite Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 avenue des Martyrs-CS10090, Grenoble cedex 9, 38044, France
| | - Alicia Vallet
- Universite Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 avenue des Martyrs-CS10090, Grenoble cedex 9, 38044, France
| | - Catherine Bougault
- Universite Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 avenue des Martyrs-CS10090, Grenoble cedex 9, 38044, France
| | - Magdalena Kaus-Drobek
- Laboratory of Protein Engineering, Mossakowski Medical Research Institute, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106, Warsaw, Poland
| | - Izabela Sabala
- International Institute of Molecular and Cell Biology in Warsaw, 4 Ks. Trojdena Street, 02-109, Warsaw, Poland.
- Laboratory of Protein Engineering, Mossakowski Medical Research Institute, Polish Academy of Sciences, 5 Pawinskiego Street, 02-106, Warsaw, Poland.
| | - Jean-Pierre Simorre
- Universite Grenoble Alpes, CNRS, CEA, Institut de Biologie Structurale, 71 avenue des Martyrs-CS10090, Grenoble cedex 9, 38044, France.
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7
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Goedseels M, Michiels CW. Cell Envelope Modifications Generating Resistance to Hop Beta Acids and Collateral Sensitivity to Cationic Antimicrobials in Listeria monocytogenes. Microorganisms 2023; 11:2024. [PMID: 37630584 PMCID: PMC10457916 DOI: 10.3390/microorganisms11082024] [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: 07/04/2023] [Revised: 08/03/2023] [Accepted: 08/04/2023] [Indexed: 08/27/2023] Open
Abstract
Hop beta acids (HBAs) are characteristic compounds from the hop plant that are of interest for their strong antimicrobial activity. In this work, we report a resistance mechanism against HBA in the foodborne pathogen Listeria monocytogenes. Using an evolution experiment, we isolated two HBA-resistant mutants with mutations in the mprF gene, which codes for the Multiple Peptide Resistance Factor, an enzyme that confers resistance to cationic peptides and antibiotics in several Gram-positive bacteria by lysinylating membrane phospholipids. Besides the deletion of mprF, the deletion of dltA, which mediates the alanylation of teichoic acids, resulted in increased HBA resistance, suggesting that resistance may be caused by a reduction in positive charges on the cell surface. Additionally, we found that this resistance is maintained at low pH, indicating that the resistance mechanism is not solely based on electrostatic interactions of HBA with the cell surface. Finally, we showed that the HBA-resistant mutants display collateral sensitivity to the cationic antimicrobials polymyxin B and nisin, which may open perspectives for combining antimicrobials to prevent resistance development.
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Affiliation(s)
| | - Chris W. Michiels
- Department of Microbial and Molecular Systems, KU Leuven, B-3000 Leuven, Belgium;
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8
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Ran W, Yue Y, Long F, Zhong K, Bai J, Xiao Y, Bu Q, Huang Y, Wu Y, Gao H. Antibacterial Mechanism of 2R,3R-Dihydromyricetin Against Staphylococcus aureus: Deciphering Inhibitory Effect on Biofilm and Virulence Based on Transcriptomic and Proteomic Analyses. Foodborne Pathog Dis 2023; 20:90-99. [PMID: 36862127 DOI: 10.1089/fpd.2022.0075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/03/2023] Open
Abstract
Staphylococcus aureus is a major foodborne pathogen that leads to various diseases due to its biofilm and virulence factors. This study aimed to investigate the inhibitory effect of 2R,3R-dihydromyricetin (DMY), a natural flavonoid compound, on the biofilm formation and virulence of S. aureus, and to explore the mode of action using transcriptomic and proteomic analyses. Microscopic observation revealed that DMY could remarkably inhibit the biofilm formation by S. aureus, leading to a collapse on the biofilm architecture and a decrease in viability of biofilm cell. Moreover, the hemolytic activity of S. aureus was reduced to 32.7% after treatment with subinhibitory concentration of DMY (p < 0.01). Bioinformation analysis based on RNA-sequencing and proteomic profiling revealed that DMY induced 262 differentially expressed genes and 669 differentially expressed proteins (p < 0.05). Many downregulated genes and proteins related to surface proteins were involved in biofilm formation, including clumping factor A (ClfA), iron-regulated surface determinants (IsdA, IsdB, and IsdC), fibrinogen-binding proteins (FnbA, FnbB), and serine protease. Meanwhile, DMY regulated a wide range of genes and proteins enriched in bacterial pathogenesis, cell envelope, amino acid metabolism, purine and pyrimidine metabolism, and pyruvate metabolism. These findings suggest that DMY targets S. aureus through multifarious mechanisms, and especially prompt that interference of surface proteins in cell envelope would lead to attenuation of biofilm and virulence.
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Affiliation(s)
- Wenyi Ran
- Department of Food Engineering, College of Biomass Science and Engineering and Healthy Food Evaluation Research Center, Sichuan University, Chengdu, China
| | - Yuxi Yue
- Department of Food Engineering, College of Biomass Science and Engineering and Healthy Food Evaluation Research Center, Sichuan University, Chengdu, China
| | - Feiwu Long
- Department of Hygienic Toxicology and Pathology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China.,Research Center for Nutrition, Metabolism and Food Safety, West China-PUMC C.C. Chen Institute of Health, Sichuan University, Chengdu, China
| | - Kai Zhong
- Department of Food Engineering, College of Biomass Science and Engineering and Healthy Food Evaluation Research Center, Sichuan University, Chengdu, China
| | - Jinrong Bai
- Department of Hygienic Toxicology and Pathology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China.,Research Center for Nutrition, Metabolism and Food Safety, West China-PUMC C.C. Chen Institute of Health, Sichuan University, Chengdu, China
| | - Yue Xiao
- Department of Hygienic Toxicology and Pathology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China.,Research Center for Nutrition, Metabolism and Food Safety, West China-PUMC C.C. Chen Institute of Health, Sichuan University, Chengdu, China
| | - Qian Bu
- Department of Hygienic Toxicology and Pathology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China.,Research Center for Nutrition, Metabolism and Food Safety, West China-PUMC C.C. Chen Institute of Health, Sichuan University, Chengdu, China
| | - Yina Huang
- Department of Hygienic Toxicology and Pathology, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China.,Research Center for Nutrition, Metabolism and Food Safety, West China-PUMC C.C. Chen Institute of Health, Sichuan University, Chengdu, China
| | - Yanping Wu
- Department of Food Engineering, College of Biomass Science and Engineering and Healthy Food Evaluation Research Center, Sichuan University, Chengdu, China
| | - Hong Gao
- Department of Food Engineering, College of Biomass Science and Engineering and Healthy Food Evaluation Research Center, Sichuan University, Chengdu, China
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9
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Han R, Feng XQ, Vollmer W, Stoodley P, Chen J. Deciphering the adaption of bacterial cell wall mechanical integrity and turgor to different chemical or mechanical environments. J Colloid Interface Sci 2023; 640:510-520. [PMID: 36878069 DOI: 10.1016/j.jcis.2023.02.100] [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: 12/28/2022] [Revised: 02/16/2023] [Accepted: 02/19/2023] [Indexed: 02/24/2023]
Abstract
Bacteria adapt the mechanical properties of their cell envelope, including cell wall stiffness, turgor, and cell wall tension and deformation, to grow and survive in harsh environments. However, it remains a technical challenge to simultaneously determine these mechanical properties at a single cell level. Here we combined theoretical modelling with an experimental approach to quantify the mechanical properties and turgor of Staphylococcus epidermidis. It was found that high osmolarity leads to a decrease in both cell wall stiffness and turgor. We also demonstrated that the turgor change is associated with a change in the viscosity of the bacterial cell. We predicted that the cell wall tension is much higher in deionized (DI) water and it decreases with an increase in osmolality. We also found that an external force increases the cell wall deformation to reinforce its adherence to a surface and this effect can be more significant in lower osmolarity. Overall, our work highlights how bacterial mechanics supports survival in harsh environments and uncovers the adaption of bacterial cell wall mechanical integrity and turgor to osmotic and mechanical challenges.
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Affiliation(s)
- Rui Han
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK
| | - Xi-Qiao Feng
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4AX, UK
| | - Paul Stoodley
- Department of Microbial Infection and Immunity and the Department of Orthopaedics, The Ohio State University, Columbus, OH 43210, United States; National Centre for Advanced Tribology at Southampton (nCATS), National Biofilm Innovation Centre (NBIC), Mechanical Engineering, University of Southampton, Southampton S017 1BJ, UK
| | - Jinju Chen
- School of Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, UK.
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10
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Sun J, Rutherford ST, Silhavy TJ, Huang KC. Physical properties of the bacterial outer membrane. Nat Rev Microbiol 2022; 20:236-248. [PMID: 34732874 PMCID: PMC8934262 DOI: 10.1038/s41579-021-00638-0] [Citation(s) in RCA: 83] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2021] [Indexed: 11/09/2022]
Abstract
It has long been appreciated that the Gram-negative outer membrane acts as a permeability barrier, but recent studies have uncovered a more expansive and versatile role for the outer membrane in cellular physiology and viability. Owing to recent developments in microfluidics and microscopy, the structural, rheological and mechanical properties of the outer membrane are becoming apparent across multiple scales. In this Review, we discuss experimental and computational studies that have revealed key molecular factors and interactions that give rise to the spatial organization, limited diffusivity and stress-bearing capacity of the outer membrane. These physical properties suggest broad connections between cellular structure and physiology, and we explore future prospects for further elucidation of the implications of outer membrane construction for cellular fitness and survival.
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Affiliation(s)
- Jiawei Sun
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Steven T. Rutherford
- Department of Infectious Diseases, Genentech Inc., South San Francisco, CA 94080, USA,To whom correspondence should be addressed: , ,
| | - Thomas J. Silhavy
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA,To whom correspondence should be addressed: , ,
| | - Kerwyn Casey Huang
- Department of Bioengineering, Stanford University, Stanford, CA, USA. .,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, CA, USA. .,Chan Zuckerberg Biohub, San Francisco, CA, USA.
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11
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Magnesium rescues the morphology of Bacillus subtilis mreB mutants through its inhibitory effect on peptidoglycan hydrolases. Sci Rep 2022; 12:1137. [PMID: 35064120 PMCID: PMC8782873 DOI: 10.1038/s41598-021-04294-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 12/06/2021] [Indexed: 02/04/2023] Open
Abstract
Cell wall homeostasis in bacteria is tightly regulated by balanced synthesis and degradation of peptidoglycan (PG), allowing cells to expand their sacculus during growth while maintaining physical integrity. In rod-shaped bacteria, actin-like MreB proteins are key players of the PG elongation machinery known as the Rod complex. In the Gram-positive model bacterium Bacillus subtilis depletion of the essential MreB leads to loss of rod shape and cell lysis. However, millimolar concentrations of magnesium in the growth medium rescue the viability and morphological defects of mreB mutants by an unknown mechanism. Here, we used a combination of cytological, biochemical and biophysical approaches to investigate the cell surface properties of mreB null mutant cells and the interactions of Mg2+ with the cell wall of B. subtilis. We show that ∆mreB cells have rougher and softer surfaces, and changes in PG composition indicative of increased DL- and DD-endopeptidase activities as well as increased deacetylation of the sugar moieties. Increase in DL-endopeptidase activity is mitigated by excess Mg2+ while DD-endopeptidase activity remains high. Visualization of PG degradation in pulse-chase experiments showed anisotropic PG hydrolase activity along the sidewalls of ∆mreB cells, in particular at the sites of increased cell width and bulging, while PG synthesis remained isotropic. Overall, our data support a model in which divalent cations maintain rod shape in ∆mreB cells by inhibiting PG hydrolases, possibly through the formation of crosslinks with carboxyl groups of the PG meshwork that affect the capacity of PG hydrolases to act on their substrate.
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12
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Sarkar K, Datta HK, Ahmed S, Dastidar P. Structural Rationale towards Designing Coordination Polymer Based Metallogels Displaying Anti‐Cancer and Anti‐Bacterial Properties. ChemistrySelect 2021. [DOI: 10.1002/slct.202103519] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Koushik Sarkar
- School of Chemical Sciences Indian Association for the Cultivation of Science 2A & 2B Raja S. C. Mullick Road Kolkata 700032 India
| | - Hemanta Kumar Datta
- School of Chemical Sciences Indian Association for the Cultivation of Science 2A & 2B Raja S. C. Mullick Road Kolkata 700032 India
| | - Sabir Ahmed
- School of Chemical Sciences Indian Association for the Cultivation of Science 2A & 2B Raja S. C. Mullick Road Kolkata 700032 India
| | - Parthasarathi Dastidar
- School of Chemical Sciences Indian Association for the Cultivation of Science 2A & 2B Raja S. C. Mullick Road Kolkata 700032 India
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13
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Ghassemi N, Poulhazan A, Deligey F, Mentink-Vigier F, Marcotte I, Wang T. Solid-State NMR Investigations of Extracellular Matrixes and Cell Walls of Algae, Bacteria, Fungi, and Plants. Chem Rev 2021; 122:10036-10086. [PMID: 34878762 DOI: 10.1021/acs.chemrev.1c00669] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Extracellular matrixes (ECMs), such as the cell walls and biofilms, are important for supporting cell integrity and function and regulating intercellular communication. These biomaterials are also of significant interest to the production of biofuels and the development of antimicrobial treatment. Solid-state nuclear magnetic resonance (ssNMR) and magic-angle spinning-dynamic nuclear polarization (MAS-DNP) are uniquely powerful for understanding the conformational structure, dynamical characteristics, and supramolecular assemblies of carbohydrates and other biomolecules in ECMs. This review highlights the recent high-resolution investigations of intact ECMs and native cells in many organisms spanning across plants, bacteria, fungi, and algae. We spotlight the structural principles identified in ECMs, discuss the current technical limitation and underexplored biochemical topics, and point out the promising opportunities enabled by the recent advances of the rapidly evolving ssNMR technology.
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Affiliation(s)
- Nader Ghassemi
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | - Alexandre Poulhazan
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States.,Department of Chemistry, Université du Québec à Montréal, Montreal H2X 2J6, Canada
| | - Fabien Deligey
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
| | | | - Isabelle Marcotte
- Department of Chemistry, Université du Québec à Montréal, Montreal H2X 2J6, Canada
| | - Tuo Wang
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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14
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Antimicrobial Properties of Chitosan and Chitosan Derivatives in the Treatment of Enteric Infections. Molecules 2021; 26:molecules26237136. [PMID: 34885715 PMCID: PMC8659174 DOI: 10.3390/molecules26237136] [Citation(s) in RCA: 81] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/20/2021] [Accepted: 11/23/2021] [Indexed: 12/26/2022] Open
Abstract
Antibiotics played an important role in controlling the development of enteric infection. However, the emergence of antibiotic resistance and gut dysbiosis led to a growing interest in the use of natural antimicrobial agents as alternatives for therapy and disinfection. Chitosan is a nontoxic natural antimicrobial polymer and is approved by GRAS (Generally Recognized as Safe by the United States Food and Drug Administration). Chitosan and chitosan derivatives can kill microbes by neutralizing negative charges on the microbial surface. Besides, chemical modifications give chitosan derivatives better water solubility and antimicrobial property. This review gives an overview of the preparation of chitosan, its derivatives, and the conjugates with other polymers and nanoparticles with better antimicrobial properties, explains the direct and indirect mechanisms of action of chitosan, and summarizes current treatment for enteric infections as well as the role of chitosan and chitosan derivatives in the antimicrobial agents in enteric infections. Finally, we suggested future directions for further research to improve the treatment of enteric infections and to develop more useful chitosan derivatives and conjugates.
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15
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Insights into the antibacterial mechanism of action of chelating agents by selective deprivation of iron, manganese and zinc. Appl Environ Microbiol 2021; 88:e0164121. [PMID: 34788072 PMCID: PMC8788741 DOI: 10.1128/aem.01641-21] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacterial growth and proliferation can be restricted by limiting the availability of metal ions in their environment. Humans sequester iron, manganese, and zinc to help prevent infection by pathogens, a system termed nutritional immunity. Commercially used chelants have high binding affinities with a variety of metal ions, which may lead to antibacterial properties that mimic these innate immune processes. However, the modes of action of many of these chelating agents in bacterial growth inhibition and their selectivity in metal deprivation in cellulo remain ill-defined. We address this shortcoming by examining the effect of 11 chelators on Escherichia coli growth and their impact on the cellular concentration of five metals. The following four distinct effects were uncovered: (i) no apparent alteration in metal composition, (ii) depletion of manganese alongside reductions in iron and zinc levels, (iii) reduced zinc levels with a modest reduction in manganese, and (iv) reduced iron levels coupled with elevated manganese. These effects do not correlate with the absolute known chelant metal ion affinities in solution; however, for at least five chelators for which key data are available, they can be explained by differences in the relative affinity of chelants for each metal ion. The results reveal significant insights into the mechanism of growth inhibition by chelants, highlighting their potential as antibacterials and as tools to probe how bacteria tolerate selective metal deprivation. IMPORTANCE Chelating agents are widely used in industry and consumer goods to control metal availability, with bacterial growth restriction as a secondary benefit for preservation. However, the antibacterial mechanism of action of chelants is largely unknown, particularly with respect to the impact on cellular metal concentrations. The work presented here uncovers distinct metal starvation effects imposed by different chelants on the model Gram-negative bacterium Escherichia coli. The chelators were studied both individually and in pairs, with the majority producing synergistic effects in combinations that maximize antibacterial hostility. The judicious selection of chelants based on contrasting cellular effects should enable reductions in the quantities of chelant required in numerous commercial products and presents opportunities to replace problematic chemistries with biodegradable alternatives.
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16
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Garner EC. Toward a Mechanistic Understanding of Bacterial Rod Shape Formation and Regulation. Annu Rev Cell Dev Biol 2021; 37:1-21. [PMID: 34186006 DOI: 10.1146/annurev-cellbio-010521-010834] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
One of the most common bacterial shapes is a rod, yet we have a limited understanding of how this simple shape is constructed. While only six proteins are required for rod shape, we are just beginning to understand how they self-organize to build the micron-sized enveloping structures that define bacterial shape out of nanometer-sized glycan strains. Here, we detail and summarize the insights gained over the last 20 years into this complex problem that have been achieved with a wide variety of different approaches. We also explain and compare both current and past models of rod shape formation and maintenance and then highlight recent insights into how the Rod complex might be regulated. Expected final online publication date for the Annual Review of Cell and Developmental Biology, Volume 37 is October 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Ethan C Garner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts, USA;
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17
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Zouhir S, Contreras-Martel C, Maragno Trindade D, Attrée I, Dessen A, Macheboeuf P. MagC is a NplC/P60-like member of the α-2-macroglobulin Mag complex of Pseudomonas aeruginosa that interacts with peptidoglycan. FEBS Lett 2021; 595:2034-2046. [PMID: 34115884 DOI: 10.1002/1873-3468.14148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 05/17/2021] [Accepted: 06/08/2021] [Indexed: 11/07/2022]
Abstract
Bacterial α-2 macroglobulins (A2Ms) structurally resemble the large spectrum protease inhibitors of the eukaryotic immune system. In Pseudomonas aeruginosa, MagD acts as an A2M and is expressed within a six-gene operon encoding the MagA-F proteins. In this work, we employ isothermal calorimetry (ITC), analytical ultracentrifugation (AUC), and X-ray crystallography to investigate the function of MagC and show that MagC associates with the macroglobulin complex and with the peptidoglycan (PG). However, the catalytic residues of MagC display an inactive conformation that could suggest that it binds to PG but does not degrade it. We hypothesize that MagC could serve as an anchor between the MagD macroglobulin and the PG and could provide stabilization and/or regulation for the entire complex.
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Affiliation(s)
- Samira Zouhir
- Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas, Brazil
| | | | | | - Ina Attrée
- Unité de Biologie Cellulaire et Infection, CEA, INSERM, CNRS, Université Grenoble Alpes, France
| | - Andréa Dessen
- Brazilian Biosciences National Laboratory (LNBio), CNPEM, Campinas, Brazil.,CNRS, CEA, IBS, Université Grenoble Alpes, France
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18
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Zhang K, Raju C, Zhong W, Pethe K, Gründling A, Chan-Park MB. Cationic Glycosylated Block Co-β-peptide Acts on the Cell Wall of Gram-Positive Bacteria as Anti-biofilm Agents. ACS APPLIED BIO MATERIALS 2021; 4:3749-3761. [PMID: 35006805 DOI: 10.1021/acsabm.0c01241] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Antimicrobial resistance is a global threat. In addition to the emergence of resistance to last resort drugs, bacteria escape antibiotics killing by forming complex biofilms. Strategies to tackle antibiotic resistance as well as biofilms are urgently needed. Wall teichoic acid (WTA), a generic anionic glycopolymer present on the cell surface of many Gram-positive bacteria, has been proposed as a possible therapeutic target, but its druggability remains to be demonstrated. Here we report a cationic glycosylated block co-β-peptide that binds to WTA. By doing so, the co-β-peptide not only inhibits biofilm formation, it also disperses preformed biofilms in several Gram-positive bacteria and resensitizes methicillin-resistant Staphylococcus aureus to oxacillin. The cationic block of the co-β-peptide physically interacts with the anionic WTA within the cell envelope, whereas the glycosylated block forms a nonfouling corona around the bacteria. This reduces physical interaction between bacteria-substrate and bacteria-biofilm matrix, leading to biofilm inhibition and dispersal. The WTA-targeting co-β-peptide is a promising lead for the future development of broad-spectrum anti-biofilm strategies against Gram-positive bacteria.
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Affiliation(s)
- Kaixi Zhang
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459.,Centre for Antimicrobial Bioengineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459
| | - Cheerlavancha Raju
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459.,Centre for Antimicrobial Bioengineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459
| | - Wenbin Zhong
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459.,Centre for Antimicrobial Bioengineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459
| | - Kevin Pethe
- Centre for Antimicrobial Bioengineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459.,Lee Kong Chian School of Medicine, Nanyang Technological University, 59 Nanyang Drive, Singapore 636921.,School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551
| | - Angelika Gründling
- Faculty of Medicine, Department of Infectious Disease, Imperial College London, Flowers Building London, London SW7 2AZ, United Kingdom
| | - Mary B Chan-Park
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459.,Centre for Antimicrobial Bioengineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459.,Lee Kong Chian School of Medicine, Nanyang Technological University, 59 Nanyang Drive, Singapore 636921
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19
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Phạm TTT, Rainey JK. On-cell nuclear magnetic resonance spectroscopy to probe cell surface interactions. Biochem Cell Biol 2021; 99:683-692. [PMID: 33945753 DOI: 10.1139/bcb-2021-0052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Nuclear magnetic resonance (NMR) spectroscopy allows determination of atomic-level information about intermolecular interactions, molecular structure, and molecular dynamics in the cellular environment. This may be broadly divided into studies focused on obtaining detailed molecular information in the intracellular context ("in-cell") or those focused on characterizing molecules or events at the cell surface ("on-cell"). In this review, we outline some key NMR techniques applied for on-cell NMR studies through both solution-state and solid-state NMR and survey studies that have used these techniques to uncover key information. We particularly focus on application of on-cell NMR spectroscopy to characterize ligand interactions with cell surface membrane proteins such as G-protein coupled receptors (GPCRs), receptor tyrosine kinases, etc. These techniques allow for quantification of binding affinities, competitive binding assays, delineation of portions of ligands involved in binding, ligand bound-state conformational determination, evaluation of receptor structuring and dynamics, and inference of distance constraints characteristic of the ligand-receptor bound state. Excitingly, it is possible to avoid the barriers of production and purification of membrane proteins while obtaining directly physiologically-relevant information through on-cell NMR. We also provide a briefer survey of the applicability of on-cell NMR approaches to other classes of cell surface molecule.
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Affiliation(s)
- Trần Thanh Tâm Phạm
- Dalhousie University, 3688, Department of Biochemistry & Molecular Biology, Halifax, Nova Scotia, Canada;
| | - Jan K Rainey
- Dalhousie University, 3688, Department of Biochemistry & Molecular Biology, Halifax, Canada;
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20
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Mullick P, Das G, Aiyagari R. Probiotic bacteria cell surface-associated protein mineralized hydroxyapatite incorporated in porous scaffold: In vitro evaluation for bone cell growth and differentiation. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2021; 126:112101. [PMID: 34082927 DOI: 10.1016/j.msec.2021.112101] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 03/18/2021] [Accepted: 04/03/2021] [Indexed: 02/06/2023]
Abstract
There is a high demand for synthesis of biocompatible hydroxyapatite nanoparticle (HANP), which is a key component in bone tissue engineering scaffolds. The present study describes a facile route of HANP synthesis through mineralization of the cell surface-associated protein (CSP) from the human probiotic lactic acid bacteria (LAB) Lactobacillus rhamnosus GG. CSP extract from the LAB (consisting of ~66 kDa, ~47 kDa, ~40 kDa and ~25 kDa protein) was mineralized to yield spindle-shaped HANPs having an average particle length of 371 nm as evidenced in FETEM analysis. CSP-mineralized HANPs (CSP-HANPs) were characterized by FTIR and BET analysis, while XRD and SAED analysis indicated their crystalline nature. Mechanistic studies suggested the key role of ~25 kDa CSP (F4SP) in mineralization. In contrast to CSP-HANPs, F4SP-mineralized crystalline HA was plate-shaped having an average length of 1.68 μm and breadth of 0.95 μm. HANP mineralization at the whole-cell (WC) level resulted in clusters of aggregated HANPs (WC-HANPs) adhering onto L. rhamnosus GG cells as evident in FETEM, FESEM and AFM analysis. FETEM analysis revealed that the desorbed WC-HANPs recovered by cell lysis were needle-shaped, with a particle size distribution of 70-110 nm. Given that CSP-HANPs were non-toxic to cultured HEK 293 cells and osteoblast-like MG-63 cells, chitosan-gelatin (CG) scaffold incorporated with 15% w/v CSP-HANP (H-CG) was generated and tested for bone cell growth. H-CG exhibited a favorable pore size distribution (160-230 μm), overall porosity (~84%) and biodegradation profile. H-CG scaffold was conducive to osteogenesis and rendered enhanced proliferation, alkaline phosphatase (ALP) activity, calcium mineralization and heightened marker gene expression (ALP, Col I, Runx2 and OCN) in seeded MG-63 cells. CSP sourced from a safe probiotic LAB is thus a viable and effective mineralization template for synthesis of biocompatible HANPs that can be leveraged for bone tissue engineering applications.
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Affiliation(s)
- Priya Mullick
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Gopal Das
- Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
| | - Ramesh Aiyagari
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
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21
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Martínez B, Rodríguez A, Kulakauskas S, Chapot-Chartier MP. Cell wall homeostasis in lactic acid bacteria: threats and defences. FEMS Microbiol Rev 2021; 44:538-564. [PMID: 32495833 PMCID: PMC7476776 DOI: 10.1093/femsre/fuaa021] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 06/03/2020] [Indexed: 12/16/2022] Open
Abstract
Lactic acid bacteria (LAB) encompasses industrially relevant bacteria involved in food fermentations as well as health-promoting members of our autochthonous microbiota. In the last years, we have witnessed major progresses in the knowledge of the biology of their cell wall, the outermost macrostructure of a Gram-positive cell, which is crucial for survival. Sophisticated biochemical analyses combined with mutation strategies have been applied to unravel biosynthetic routes that sustain the inter- and intra-species cell wall diversity within LAB. Interplay with global cell metabolism has been deciphered that improved our fundamental understanding of the plasticity of the cell wall during growth. The cell wall is also decisive for the antimicrobial activity of many bacteriocins, for bacteriophage infection and for the interactions with the external environment. Therefore, genetic circuits involved in monitoring cell wall damage have been described in LAB, together with a plethora of defence mechanisms that help them to cope with external threats and adapt to harsh conditions. Since the cell wall plays a pivotal role in several technological and health-promoting traits of LAB, we anticipate that this knowledge will pave the way for the future development and extended applications of LAB.
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Affiliation(s)
- Beatriz Martínez
- DairySafe research group. Department of Technology and Biotechnology of Dairy Products. Instituto de Productos Lácteos de Asturias, IPLA-CSIC. Paseo Río Linares s/n. 33300 Villaviciosa, Spain
| | - Ana Rodríguez
- DairySafe research group. Department of Technology and Biotechnology of Dairy Products. Instituto de Productos Lácteos de Asturias, IPLA-CSIC. Paseo Río Linares s/n. 33300 Villaviciosa, Spain
| | - Saulius Kulakauskas
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, 78350, Jouy-en-Josas, France
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22
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Shiny Matilda C, Mannully ST, Rao VP, Shanthi C. Chromium binding Bacillus cereus VITSH1-a promising candidate for heavy metal clean up. Lett Appl Microbiol 2021; 72:517-525. [PMID: 33331052 DOI: 10.1111/lam.13441] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 12/08/2020] [Accepted: 12/08/2020] [Indexed: 11/28/2022]
Abstract
Bacteria survive metal stress by several mechanisms and metal binding is one such mechanism which has been screened in the present study to investigate the survival strategies of metal resistant bacteria. The production of siderophores, a metal chelating agent, was detected by chrome azurol S agar assay. The changes in cell wall studied by analysing the peptidoglycan and teichoic acid content indicated an increase in the cell wall content. Evaluation of morphological and physiological alterations like cell size, granularity analysed by SEM and flow cytometry analysis revealed an increase in cell size and granularity respectively. The transformation of phosphates monitored by 31 P NMR analysis indicated the presence of inorganic phosphate. Based on the cell wall changes and the 31 P NMR analysis, the surface charge of the organism was studied by zeta potential which displayed a difference at pH7.
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Affiliation(s)
- C Shiny Matilda
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India
| | - S T Mannully
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India
| | - V P Rao
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India
| | - C Shanthi
- School of Bio Sciences and Technology, Vellore Institute of Technology, Vellore, India
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23
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Solving the structural puzzle of bacterial glycome. Curr Opin Struct Biol 2021; 68:74-83. [PMID: 33434849 DOI: 10.1016/j.sbi.2020.12.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 11/30/2020] [Accepted: 12/03/2020] [Indexed: 11/22/2022]
Abstract
The analysis of the bacterial glycome (glycomics) is among the complex 'omics' analysis owing to the inherent difficulties in structural and functional characterization of glycans. The complexity and variability of bacterial glycans, spanning from simple carbohydrates to complex glycolipids, glycopeptides and glycoproteins, make their study a challenging research area. The last two decades have witnessed tremendous advances and development of highly sophisticated methods, in combination with optimized protocols and hyphenate techniques for the understanding of structure, conformations, dynamics and organization of microbial glycans. We here present an overview of the novel approaches that have massively improved our understanding of the carbohydrate-based world of bacteria.
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24
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Gordesli-Duatepe FP, Park BJ, Kawas LH, Abu-Lail NI. Atomic Force Microscopy Investigation of the Contributions of Listeria monocytogenes Cell-Wall Biomacromolecules to Their Adherence and Mechanics. J Phys Chem B 2020; 124:5872-5883. [PMID: 32544332 DOI: 10.1021/acs.jpcb.0c04025] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this work, the contributions of the pathogenic Listeria monocytogenes cell-wall biomacromolecules to the bacterial mechanics and adhesion to a model inert surface of silicon nitride in water were investigated by atomic force microscopy. Chemical ethylenediaminetetraacetic acid (EDTA) and biological enzymatic trypsin treatments of cells were performed to partially or totally remove the bacterial cell-wall proteins and carbohydrates. Removal of 48.2% proteins and 29.2% of carbohydrates from the cell-wall of the bacterium by the EDTA treatment resulted in a significant decrease in the length of the bacterial cell-wall biomacromolecules and an increase in the rigidity of the bacterial cells as predicted from fitting a model of steric repulsion to the force-distance approach data and classic Hertz model to the indentation-force data, respectively. In comparison, removal of almost all the cell-wall proteins (99.5% removal) and 8.6% of cell-wall carbohydrates by the trypsin treatment resulted in an increase in the elasticity of the bacterial cells, an increase in the extension of the cell-wall biomacromolecules, and a significant decrease in their apparent grafting densities. In addition, adhesion strength of native-untreated L. monocytogenes to silicon nitride in water decreased by 30% on average after the EDTA treatment and further decreased by 60% on average after the trypsin treatment, showing a positive correlation with the% removal of cell-wall proteins by the EDTA and trypsin treatments, respectively.
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Affiliation(s)
- F Pinar Gordesli-Duatepe
- Department of Genetics and Bioengineering, Faculty of Engineering, Izmir University of Economics, 35330 Izmir, Turkey
| | - Bong J Park
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, Washington 99164, United States
| | - Leen H Kawas
- Department of Veterinary and Comparative Anatomy, Pharmacology, and Physiology, Washington State University Pullman, Washington 99164-6520, United States
| | - Nehal I Abu-Lail
- Department of Biomedical Engineering and Chemical Engineering, The University of Texas at San Antonio, San Antonio, Texas 78249, United States
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25
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Zhao W, Fernando LD, Kirui A, Deligey F, Wang T. Solid-state NMR of plant and fungal cell walls: A critical review. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2020; 107:101660. [PMID: 32251983 DOI: 10.1016/j.ssnmr.2020.101660] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 03/17/2020] [Indexed: 05/22/2023]
Abstract
The cell walls of plants and microbes are a central source for bio-renewable energy and the major targets of antibiotics and antifungal agents. It is highly challenging to determine the molecular structure of complex carbohydrates, protein and lignin, and their supramolecular assembly in intact cell walls. This article selectively highlights the recent breakthroughs that employ 13C/15N solid-state NMR techniques to elucidate the architecture of fungal cell walls in Aspergillus fumigatus and the primary and secondary cell walls in a large variety of plant species such as Arabidopsis, Brachypodium, maize, and spruce. Built upon these pioneering studies, we further summarize the underexplored aspects of fungal and plant cell walls. The new research opportunities introduced by innovative methods, such as the detection of proton and quadrupolar nuclei on ultrahigh-field magnets and under fast magic-angle spinning, paramagnetic probes, natural-abundance DNP, and software development, are also critically discussed.
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Affiliation(s)
- Wancheng Zhao
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Liyanage D Fernando
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Alex Kirui
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Fabien Deligey
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Tuo Wang
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA.
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26
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Kang X, Zhao W, Dickwella Widanage MC, Kirui A, Ozdenvar U, Wang T. CCMRD: a solid-state NMR database for complex carbohydrates. JOURNAL OF BIOMOLECULAR NMR 2020; 74:239-245. [PMID: 32125579 DOI: 10.1007/s10858-020-00304-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 01/27/2020] [Indexed: 05/03/2023]
Abstract
Carbohydrates are essential to various life activities in living organisms and serve as the central component in many biomaterials. As an emerging technique with steadily improving resolution, solid-state Nuclear Magnetic Resonance (NMR) spectroscopy has the unique capability in revealing the polymorphic structure and heterogeneous dynamics of insoluble complex carbohydrates. Here, we report the first solid-state NMR database for complex carbohydrates, Complex Carbohydrates Magnetic Resonance Database (CCMRD). This database currently holds the chemical shift information of more than four hundred solid-state NMR compounds and expects rapid expansion. CCMRD provides open portals for data deposition and supports search options based on NMR chemical shifts, carbohydrate names, and compound classes. With the timely implementation, this platform will facilitate spectral analysis and structure determination of carbohydrates and promote software development to benefit the research community. The database is freely accessible at www.ccmrd.org.
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Affiliation(s)
- Xue Kang
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA.
| | - Wancheng Zhao
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA
| | | | - Alex Kirui
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Uluc Ozdenvar
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA
| | - Tuo Wang
- Department of Chemistry, Louisiana State University, Baton Rouge, LA, 70803, USA.
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27
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Domain sliding of two Staphylococcus aureus N-acetylglucosaminidases enables their substrate-binding prior to its catalysis. Commun Biol 2020; 3:178. [PMID: 32313083 PMCID: PMC7170848 DOI: 10.1038/s42003-020-0911-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 03/23/2020] [Indexed: 12/22/2022] Open
Abstract
To achieve productive binding, enzymes and substrates must align their geometries to complement each other along an entire substrate binding site, which may require enzyme flexibility. In pursuit of novel drug targets for the human pathogen S. aureus, we studied peptidoglycan N-acetylglucosaminidases, whose structures are composed of two domains forming a V-shaped active site cleft. Combined insights from crystal structures supported by site-directed mutagenesis, modeling, and molecular dynamics enabled us to elucidate the substrate binding mechanism of SagB and AtlA-gl. This mechanism requires domain sliding from the open form observed in their crystal structures, leading to polysaccharide substrate binding in the closed form, which can enzymatically process the bound substrate. We suggest that these two hydrolases must exhibit unusual extents of flexibility to cleave the rigid structure of a bacterial cell wall.
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28
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Caudill ER, Hernandez RT, Johnson KP, O'Rourke JT, Zhu L, Haynes CL, Feng ZV, Pedersen JA. Wall teichoic acids govern cationic gold nanoparticle interaction with Gram-positive bacterial cell walls. Chem Sci 2020; 11:4106-4118. [PMID: 34122876 PMCID: PMC8152635 DOI: 10.1039/c9sc05436g] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Accepted: 03/20/2020] [Indexed: 11/21/2022] Open
Abstract
Molecular-level understanding of nanomaterial interactions with bacterial cell surfaces can facilitate design of antimicrobial and antifouling surfaces and inform assessment of potential consequences of nanomaterial release into the environment. Here, we investigate the interaction of cationic nanoparticles with the main surface components of Gram-positive bacteria: peptidoglycan and teichoic acids. We employed intact cells and isolated cell walls from wild type Bacillus subtilis and two mutant strains differing in wall teichoic acid composition to investigate interaction with gold nanoparticles functionalized with cationic, branched polyethylenimine. We quantified nanoparticle association with intact cells by flow cytometry and determined sites of interaction by solid-state 31P- and 13C-NMR spectroscopy. We find that wall teichoic acid structure and composition were important determinants for the extent of interaction with cationic gold nanoparticles. The nanoparticles interacted more with wall teichoic acids from the wild type and mutant lacking glucose in its wall teichoic acids than those from the mutant having wall teichoic acids lacking alanine and exhibiting more restricted molecular motion. Our experimental evidence supports the interpretation that electrostatic forces contributed to nanoparticle-cell interactions and that the accessibility of negatively charged moieties in teichoic acid chains influences the degree of interaction. The approaches employed in this study can be applied to engineered nanomaterials differing in core composition, shape, or surface functional groups as well as to other types of bacteria to elucidate the influence of nanoparticle and cell surface properties on interactions with Gram-positive bacteria.
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Affiliation(s)
- Emily R Caudill
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
| | | | - Kyle P Johnson
- Department of Chemistry, University of Minnesota Minneapolis MN 55455 USA
| | - James T O'Rourke
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
| | - Lingchao Zhu
- Department of Chemistry, University of Pennsylvania 231 S 34th St Philadelphia PA 19104 USA
| | - Christy L Haynes
- Department of Chemistry, University of Minnesota Minneapolis MN 55455 USA
| | - Z Vivian Feng
- Chemistry Department, Augsburg University Minneapolis MN 55454 USA
| | - Joel A Pedersen
- Department of Chemistry, University of Wisconsin-Madison 1101 University Avenue Madison WI 53706 USA
- Environmental Chemistry and Technology Program, University of Wisconsin-Madison 660 North Part Street Madison WI 53706 USA
- Department of Soil Science, University of Wisconsin-Madison 1525 Observatory Drive Madison WI 53706 USA
- Department of Civil & Environmental Engineering, University of Wisconsin-Madison 1415 Engineering Drive Madison WI 53706 USA
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29
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Disruption of l-Rhamnose Biosynthesis Results in Severe Growth Defects in Streptococcus mutans. J Bacteriol 2020; 202:JB.00728-19. [PMID: 31871035 DOI: 10.1128/jb.00728-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 12/19/2019] [Indexed: 12/11/2022] Open
Abstract
The rhamnose-glucose cell wall polysaccharide (RGP) of Streptococcus mutans plays a significant role in cell division, virulence, and stress protection. Prior studies examined function of the RGP using strains carrying deletions in the machinery involved in RGP assembly. In this study, we explored loss of the substrate for RGP, l-rhamnose, via deletion of rmlD (encoding the protein responsible for the terminal step in l-rhamnose biosynthesis). We demonstrate that loss of rhamnose biosynthesis causes a phenotype similar to strains with disrupted RGP assembly (ΔrgpG and ΔrgpF strains). Deletion of rmlD not only caused a severe growth defect under nonstress growth conditions but also elevated susceptibility of the strain to acid and oxidative stress, common conditions found in the oral cavity. A genetic complement of the ΔrmlD strain completely restored wild-type levels of growth, whereas addition of exogenous rhamnose did not. The loss of rhamnose production also significantly disrupted biofilm formation, an important aspect of S. mutans growth in the oral cavity. Further, we demonstrate that loss of either rmlD or rgpG results in ablation of rhamnose content in the S. mutans cell wall. Taken together, these results highlight the importance of rhamnose production in both the fitness and the ability of S. mutans to overcome environmental stresses.IMPORTANCE Streptococcus mutans is a pathogenic bacterium that is the primary etiologic agent of dental caries, a disease that affects billions yearly. Rhamnose biosynthesis is conserved not only in streptococcal species but in other Gram-positive, as well as Gram-negative, organisms. This study highlights the importance of rhamnose biosynthesis in RGP production for protection of the organism against acid and oxidative stresses, the two major stressors that the organism encounters in the oral cavity. Loss of RGP also severely impacts biofilm formation, the first step in the onset of dental caries. The high conservation of the rhamnose synthesis enzymes, as well as their importance in S. mutans and other organisms, makes them favorable antibiotic targets for the treatment of disease.
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Abstract
Dating back to the 1960s, initial studies on the staphylococcal cell wall were driven by the need to clarify the mode of action of the first antibiotics and the resistance mechanisms developed by the bacteria. During the following decades, the elucidation of the biosynthetic path and primary composition of staphylococcal cell walls was propelled by advances in microbial cell biology, specifically, the introduction of high-resolution analytical techniques and molecular genetic approaches. The field of staphylococcal cell wall gradually gained its own significance as the complexity of its chemical structure and involvement in numerous cellular processes became evident, namely its versatile role in host interactions, coordination of cell division and environmental stress signaling.This chapter includes an updated description of the anatomy of staphylococcal cell walls, paying particular attention to information from the last decade, under four headings: high-resolution analysis of the Staphylococcus aureus peptidoglycan; variations in peptidoglycan composition; genetic determinants and enzymes in cell wall synthesis; and complex functions of cell walls. The latest contributions to a more precise picture of the staphylococcal cell envelope were possible due to recently developed state-of-the-art microscopy and spectroscopy techniques and to a wide combination of -omics approaches, that are allowing to obtain a more integrative view of this highly dynamic structure.
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31
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Siegal G, Selenko P. Cells, drugs and NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 306:202-212. [PMID: 31358370 DOI: 10.1016/j.jmr.2019.07.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 06/08/2019] [Accepted: 07/08/2019] [Indexed: 05/18/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a versatile tool for investigating cellular structures and their compositions. While in vivo and whole-cell NMR have a long tradition in cell-based approaches, high-resolution in-cell NMR spectroscopy is a new addition to these methods. In recent years, technological advancements in multiple areas provided converging benefits for cellular MR applications, especially in terms of robustness, reproducibility and physiological relevance. Here, we review the use of cellular NMR methods for drug discovery purposes in academia and industry. Specifically, we discuss how developments in NMR technologies such as miniaturized bioreactors and flow-probe perfusion systems have helped to consolidate NMR's role in cell-based drug discovery efforts.
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Affiliation(s)
- Gregg Siegal
- ZoBio B.V., BioPartner 2 Building, J.H. Oortweg 19, 2333 Leiden, the Netherlands
| | - Philipp Selenko
- Department of Biological Regulation, Weizmann Institute of Science, 234 Herzl Street, 761000 Rehovot, Israel.
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32
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Extracellular electron transfer features of Gram-positive bacteria. Anal Chim Acta 2019; 1076:32-47. [PMID: 31203962 DOI: 10.1016/j.aca.2019.05.007] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/23/2019] [Accepted: 05/05/2019] [Indexed: 12/20/2022]
Abstract
Electroactive microorganisms possess the unique ability to transfer electrons to or from solid phase electron conductors, e.g., electrodes or minerals, through various physiological mechanisms. The processes are commonly known as extracellular electron transfer and broadly harnessed in microbial electrochemical systems, such as microbial biosensors, microbial electrosynthesis, or microbial fuel cells. Apart from a few model microorganisms, the nature of the microbe-electrode conductive interaction is poorly understood for most of the electroactive species. The interaction determines the efficiency and a potential scaling up of bioelectrochemical systems. Gram-positive bacteria generally have a thick electron non-conductive cell wall and are believed to exhibit weak extracellular electron shuttling activity. This review highlights reported research accomplishments on electroactive Gram-positive bacteria. The use of electron-conducting polymers as mediators is considered as one promising strategy to enhance the electron transfer efficiency up to application scale. In view of the recent progress in understanding the molecular aspects of the extracellular electron transfer mechanisms of Enterococcus faecalis, the electron transfer properties of this bacterium are especially focused on. Fundamental knowledge on the nature of microbial extracellular electron transfer and its possibilities can provide insight in interspecies electron transfer and biogeochemical cycling of elements in nature. Additionally, a comprehensive understanding of cell-electrode interactions may help in overcoming insufficient electron transfer and restricted operational performance of various bioelectrochemical systems and facilitate their practical applications.
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Maya-Martinez R, Alexander JAN, Otten CF, Ayala I, Vollmer D, Gray J, Bougault CM, Burt A, Laguri C, Fonvielle M, Arthur M, Strynadka NCJ, Vollmer W, Simorre JP. Recognition of Peptidoglycan Fragments by the Transpeptidase PBP4 From Staphylococcus aureus. Front Microbiol 2019; 9:3223. [PMID: 30713527 PMCID: PMC6346638 DOI: 10.3389/fmicb.2018.03223] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2018] [Accepted: 12/11/2018] [Indexed: 11/13/2022] Open
Abstract
Peptidoglycan (PG) is an essential component of the cell envelope, maintaining bacterial cell shape and protecting it from bursting due to turgor pressure. The monoderm bacterium Staphylococcus aureus has a highly cross-linked PG, with ~90% of peptide stems participating in DD-cross-links and up to 15 peptide stems connected with each other. These cross-links are formed in transpeptidation reactions catalyzed by penicillin-binding proteins (PBPs) of classes A and B. Most S. aureus strains have three housekeeping PBPs with this function (PBP1, PBP2, and PBP3) but MRSA strains have acquired a third class B PBP, PBP2a, which is encoded by the mecA gene and required for the expression of high-level resistance to β-lactams. Another housekeeping PBP of S. aureus is PBP4, which belongs to the class C PBPs, and hence would be expected to have PG hydrolase (DD-carboxypeptidase or DD-endopeptidase) activity. However, previous works showed that, unexpectedly, PBP4 has transpeptidase activity that significantly contributes to both the high level of cross-linking in the PG of S. aureus and to the low level of β-lactam resistance in the absence of PBP2a. To gain insights into this unusual activity of PBP4, we studied by NMR spectroscopy its interaction in vitro with different substrates, including intact peptidoglycan, synthetic peptide stems, muropeptides, and long glycan chains with uncross-linked peptide stems. PBP4 showed no affinity for the complex, intact peptidoglycan or the smallest isolated peptide stems. Transpeptidase activity of PBP4 was verified with the disaccharide peptide subunits (muropeptides) in vitro, producing cyclic dimer and multimer products; these assays also showed a designed PBP4(S75C) nucleophile mutant to be inactive. Using this inactive but structurally highly similar variant, liquid-state NMR identified two interaction surfaces in close proximity to the central nucleophile position that can accommodate the potential donor and acceptor stems for the transpeptidation reaction. A PBP4:muropeptide model structure was built from these experimental restraints, which provides new mechanistic insights into mecA independent resistance to β-lactams in S. aureus.
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Affiliation(s)
| | - J Andrew N Alexander
- Department of Biochemistry and Molecular Biology and Centre for Blood Research, The University of British Columbia, Vancouver, BC, Canada
| | - Christian F Otten
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Isabel Ayala
- University Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | - Daniela Vollmer
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Joe Gray
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | | | - Alister Burt
- University Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | - Cédric Laguri
- University Grenoble Alpes, CNRS, CEA, IBS, Grenoble, France
| | - Matthieu Fonvielle
- Centre de Recherche des Cordeliers, LRMA, Equipe 12, Université Sorbone-Paris, Paris, France
| | - Michel Arthur
- Centre de Recherche des Cordeliers, LRMA, Equipe 12, Université Sorbone-Paris, Paris, France
| | - Natalie C J Strynadka
- Department of Biochemistry and Molecular Biology and Centre for Blood Research, The University of British Columbia, Vancouver, BC, Canada
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
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Inactivation of the Monofunctional Peptidoglycan Glycosyltransferase SgtB Allows Staphylococcus aureus To Survive in the Absence of Lipoteichoic Acid. J Bacteriol 2018; 201:JB.00574-18. [PMID: 30322854 PMCID: PMC6287468 DOI: 10.1128/jb.00574-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 10/08/2018] [Indexed: 12/29/2022] Open
Abstract
The bacterial cell wall acts as a primary defense against environmental insults such as changes in osmolarity. It is also a vulnerable structure, as defects in its synthesis can lead to growth arrest or cell death. The important human pathogen Staphylococcus aureus has a typical Gram-positive cell wall, which consists of peptidoglycan and the anionic polymers LTA and wall teichoic acid. Several clinically relevant antibiotics inhibit the synthesis of peptidoglycan; therefore, it and teichoic acids are considered attractive targets for the development of new antimicrobials. We show that LTA is required for efficient peptidoglycan cross-linking in S. aureus and inactivation of a peptidoglycan glycosyltransferase can partially rescue this defect, together revealing an intimate link between peptidoglycan and LTA synthesis. The cell wall of Staphylococcus aureus is composed of peptidoglycan and the anionic polymers lipoteichoic acid (LTA) and wall teichoic acid. LTA is required for growth and normal cell morphology in S. aureus. Strains lacking LTA are usually viable only when grown under osmotically stabilizing conditions or after the acquisition of compensatory mutations. LTA-negative suppressor strains with inactivating mutations in gdpP, which resulted in increased intracellular c-di-AMP levels, were described previously. Here, we sought to identify factors other than c-di-AMP that allow S. aureus to survive without LTA. LTA-negative strains able to grow in unsupplemented medium were obtained and found to contain mutations in sgtB, mazE, clpX, or vraT. The growth improvement through mutations in mazE and sgtB was confirmed by complementation analysis. We also showed that an S. aureussgtB transposon mutant, with the monofunctional peptidoglycan glycosyltransferase SgtB inactivated, displayed a 4-fold increase in the MIC of oxacillin, suggesting that alterations in the peptidoglycan structure could help bacteria compensate for the lack of LTA. Muropeptide analysis of peptidoglycans isolated from a wild-type strain and sgtB mutant strain did not reveal any sizable alterations in the peptidoglycan structure. In contrast, the peptidoglycan isolated from an LTA-negative ltaS mutant strain showed a significant reduction in the fraction of highly cross-linked peptidoglycan, which was partially rescued in the sgtB ltaS double mutant suppressor strain. Taken together, these data point toward an important function of LTA in cell wall integrity through its necessity for proper peptidoglycan assembly. IMPORTANCE The bacterial cell wall acts as a primary defense against environmental insults such as changes in osmolarity. It is also a vulnerable structure, as defects in its synthesis can lead to growth arrest or cell death. The important human pathogen Staphylococcus aureus has a typical Gram-positive cell wall, which consists of peptidoglycan and the anionic polymers LTA and wall teichoic acid. Several clinically relevant antibiotics inhibit the synthesis of peptidoglycan; therefore, it and teichoic acids are considered attractive targets for the development of new antimicrobials. We show that LTA is required for efficient peptidoglycan cross-linking in S. aureus and inactivation of a peptidoglycan glycosyltransferase can partially rescue this defect, together revealing an intimate link between peptidoglycan and LTA synthesis.
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35
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Laguri C, Silipo A, Martorana AM, Schanda P, Marchetti R, Polissi A, Molinaro A, Simorre JP. Solid State NMR Studies of Intact Lipopolysaccharide Endotoxin. ACS Chem Biol 2018; 13:2106-2113. [PMID: 29965728 DOI: 10.1021/acschembio.8b00271] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Lipopolysaccharides (LPS) are complex glycolipids forming the outside layer of Gram-negative bacteria. Their hydrophobic and heterogeneous nature greatly hampers their structural study in an environment similar to the bacterial surface. We have studied LPS purified from E. coli and pathogenic P. aeruginosa with long O-antigen polysaccharides assembled in solution as vesicles or elongated micelles. Solid-state NMR with magic-angle spinning permitted the identification of NMR signals arising from regions with different flexibilities in the LPS, from the lipid components to the O-antigen polysaccharides. Atomic scale data on the LPS enabled the study of the interaction of gentamicin antibiotic bound to P. aeruginosa LPS, for which we could confirm that a specific oligosaccharide is involved in the antibiotic binding. The possibility to study LPS alone and bound to a ligand when it is assembled in membrane-like structures opens great prospects for the investigation of proteins and antibiotics that specifically target such an important molecule at the surface of Gram-negative bacteria.
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Affiliation(s)
- Cedric Laguri
- Université Grenoble Alpes, CNRS, CEA, IBS, F-38000 Grenoble, France
| | - Alba Silipo
- University of Naples Federico II, Department of Chemical Sciences, via cintia 4, Napoli, Italy
| | - Alessandra M. Martorana
- University of Milano, Department of Pharmacological and Biomolecular Sciences, Via Balzaretti 9, Milano, Italy
| | - Paul Schanda
- Université Grenoble Alpes, CNRS, CEA, IBS, F-38000 Grenoble, France
| | - Roberta Marchetti
- University of Naples Federico II, Department of Chemical Sciences, via cintia 4, Napoli, Italy
| | - Alessandra Polissi
- University of Milano, Department of Pharmacological and Biomolecular Sciences, Via Balzaretti 9, Milano, Italy
| | - Antonio Molinaro
- University of Naples Federico II, Department of Chemical Sciences, via cintia 4, Napoli, Italy
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36
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Bougault C, Ayala I, Vollmer W, Simorre JP, Schanda P. Studying intact bacterial peptidoglycan by proton-detected NMR spectroscopy at 100 kHz MAS frequency. J Struct Biol 2018; 206:66-72. [PMID: 30031884 DOI: 10.1016/j.jsb.2018.07.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 06/19/2018] [Accepted: 07/12/2018] [Indexed: 12/19/2022]
Abstract
The bacterial cell wall is composed of the peptidoglycan (PG), a large polymer that maintains the integrity of the bacterial cell. Due to its multi-gigadalton size, heterogeneity, and dynamics, atomic-resolution studies are inherently complex. Solid-state NMR is an important technique to gain insight into its structure, dynamics and interactions. Here, we explore the possibilities to study the PG with ultra-fast (100 kHz) magic-angle spinning NMR. We demonstrate that highly resolved spectra can be obtained, and show strategies to obtain site-specific resonance assignments and distance information. We also explore the use of proton-proton correlation experiments, thus opening the way for NMR studies of intact cell walls without the need for isotope labeling.
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Affiliation(s)
- Catherine Bougault
- Univ. Grenoble Alpes, CEA, CNRS, Institute for Structural Biology (IBS), 71 avenue des martyrs, 38044 Grenoble, France
| | - Isabel Ayala
- Univ. Grenoble Alpes, CEA, CNRS, Institute for Structural Biology (IBS), 71 avenue des martyrs, 38044 Grenoble, France
| | - Waldemar Vollmer
- The Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Richardson Road, Newcastle upon Tyne NE2 4AX, United Kingdom
| | - Jean-Pierre Simorre
- Univ. Grenoble Alpes, CEA, CNRS, Institute for Structural Biology (IBS), 71 avenue des martyrs, 38044 Grenoble, France.
| | - Paul Schanda
- Univ. Grenoble Alpes, CEA, CNRS, Institute for Structural Biology (IBS), 71 avenue des martyrs, 38044 Grenoble, France.
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37
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Romaniuk JAH, Cegelski L. Peptidoglycan and Teichoic Acid Levels and Alterations in Staphylococcus aureus by Cell-Wall and Whole-Cell Nuclear Magnetic Resonance. Biochemistry 2018; 57:3966-3975. [PMID: 29806458 PMCID: PMC6309457 DOI: 10.1021/acs.biochem.8b00495] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Gram-positive bacteria surround themselves with a multilayered macromolecular cell wall that is essential to cell survival and serves as a major target for antibiotics. The cell wall of Staphylococcus aureus is composed of two major structural components, peptidoglycan (PG) and wall teichoic acid (WTA), together creating a heterogeneous and insoluble matrix that poses a challenge to quantitative compositional analysis. Here, we present 13C cross polarization magic angle spinning solid-state nuclear magnetic resonance (NMR) spectra of intact cell walls, purified PG, and purified WTA. The spectra reveal the clear molecular differences in the two polymers and enable quantification of PG and WTA in isolated cell walls, an attractive alternative to estimating teichoic acid content from a phosphate analysis of completely pyrolyzed cell walls. Furthermore, we discovered that unique PG and WTA spectral signatures could be identified in whole-cell NMR spectra and used to compare PG and WTA levels among intact bacterial cell samples. The distinguishing whole-cell 13C NMR contributions associated with PG include the GlcNAc-MurNAc sugar carbons and glycyl α-carbons. WTA contributes carbons from the phosphoribitol backbone. Distinguishing 15N spectral signatures include glycyl amide nitrogens in PG and the esterified d-alanyl amine nitrogens in WTA. 13C NMR analysis was performed with samples at natural abundance and included 10 whole-cell sample comparisons. Changes consistent with altered PG and WTA content were detected in whole-cell spectra of bacteria harvested at different growth times and in cells treated with tunicamycin. This use of whole-cell NMR provides quantitative parameters of composition in the context of whole-cell activity.
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Affiliation(s)
| | - Lynette Cegelski
- Stanford University, Department of Chemistry, 380 Roth Way, Stanford CA 94305
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38
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Hussain S, Wivagg CN, Szwedziak P, Wong F, Schaefer K, Izoré T, Renner LD, Holmes MJ, Sun Y, Bisson-Filho AW, Walker S, Amir A, Löwe J, Garner EC. MreB filaments align along greatest principal membrane curvature to orient cell wall synthesis. eLife 2018; 7:32471. [PMID: 29469806 PMCID: PMC5854468 DOI: 10.7554/elife.32471] [Citation(s) in RCA: 116] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 02/21/2018] [Indexed: 12/26/2022] Open
Abstract
MreB is essential for rod shape in many bacteria. Membrane-associated MreB filaments move around the rod circumference, helping to insert cell wall in the radial direction to reinforce rod shape. To understand how oriented MreB motion arises, we altered the shape of Bacillus subtilis. MreB motion is isotropic in round cells, and orientation is restored when rod shape is externally imposed. Stationary filaments orient within protoplasts, and purified MreB tubulates liposomes in vitro, orienting within tubes. Together, this demonstrates MreB orients along the greatest principal membrane curvature, a conclusion supported with biophysical modeling. We observed that spherical cells regenerate into rods in a local, self-reinforcing manner: rapidly propagating rods emerge from small bulges, exhibiting oriented MreB motion. We propose that the coupling of MreB filament alignment to shape-reinforcing peptidoglycan synthesis creates a locally-acting, self-organizing mechanism allowing the rapid establishment and stable maintenance of emergent rod shape. Many bacteria are surrounded by both a cell membrane and a cell wall – a rigid outer covering made of sugars and short protein chains. The cell wall often determines which of a variety of shapes – such as rods or spheres – the bacteria grow into. One protein required to form the rod shape is called MreB. This protein forms filaments that bind to the bacteria’s cell membrane and associate with the enzymes that build the cell wall. Together, these filament-enzyme complexes rotate around the cell to build and reinforce the cell wall in a hoop-like manner. But how do the MreB filaments know how to move around the circumference of the rod, instead of moving in any other direction? Using a technique called total internal reflection microscopy to study how MreB filaments move across bacteria cells, Hussain, Wivagg et al. show that the filaments sense the shape of a bacterium by orienting along the direction of greatest curvature. As a result, the filaments in rod-shaped cells orient and move around the rod, while in spherical bacteria they move in all directions. However, spherical bacteria can regenerate into rods from small surface ‘bulges’. The MreB filaments in the bulges move in an oriented way, helping them to generate the rod shape. Hussain, Wivagg et al. also found that forcing cells that lack a cell wall into a rod shape caused the MreB filaments bound to the cell membrane to orient and circle around the rod. This shows that the organization of the filaments is sufficient to shape the cell wall. In the future, determining what factors control the activity of the MreB filaments and the enzymes they associate with might reveal new targets for antibiotics that disrupt the cell wall and so kill the bacteria. This will require higher resolution microscopes to be used to examine the cell wall in more detail. The activity of all the proteins involved in building cell walls will also need to be extensively characterized.
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Affiliation(s)
- Saman Hussain
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Carl N Wivagg
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Piotr Szwedziak
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Felix Wong
- Harvard John A. Paulson School of Engineering and Applied Sciences, Cambridge, United States
| | - Kaitlin Schaefer
- Department of Microbiology and Immunology, Harvard University, Cambridge, United States
| | - Thierry Izoré
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Lars D Renner
- Leibniz Institute of Polymer Research, Dresden, Germany
| | - Matthew J Holmes
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Yingjie Sun
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | | | - Suzanne Walker
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, United States
| | - Ariel Amir
- Harvard John A. Paulson School of Engineering and Applied Sciences, Cambridge, United States
| | - Jan Löwe
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Ethan C Garner
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
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Ślusarz R, Samaszko-Fiertek J, Dmochowska B, Madaj J. Molecular dynamics study on the influence of C-terminal sugar substitution on dynamics and conformation of vancomycin derivatives. J Carbohydr Chem 2017. [DOI: 10.1080/07328303.2017.1347669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Rafał Ślusarz
- Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland
| | | | | | - Janusz Madaj
- Faculty of Chemistry, University of Gdańsk, Gdańsk, Poland
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40
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Li C, Zhao J, Cheng K, Ge Y, Wu Q, Ye Y, Xu G, Zhang Z, Zheng W, Zhang X, Zhou X, Pielak G, Liu M. Magnetic Resonance Spectroscopy as a Tool for Assessing Macromolecular Structure and Function in Living Cells. ANNUAL REVIEW OF ANALYTICAL CHEMISTRY (PALO ALTO, CALIF.) 2017; 10:157-182. [PMID: 28301750 DOI: 10.1146/annurev-anchem-061516-045237] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Investigating the structure, modification, interaction, and function of biomolecules in their native cellular environment leads to physiologically relevant knowledge about their mechanisms, which will benefit drug discovery and design. In recent years, nuclear and electron magnetic resonance (NMR) spectroscopy has emerged as a useful tool for elucidating the structure and function of biomacromolecules, including proteins, nucleic acids, and carbohydrates in living cells at atomic resolution. In this review, we summarize the progress and future of in-cell NMR as it is applied to proteins, nucleic acids, and carbohydrates.
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Affiliation(s)
- Conggang Li
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; ,
| | - Jiajing Zhao
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; ,
| | - Kai Cheng
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; ,
| | - Yuwei Ge
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; ,
| | - Qiong Wu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; ,
| | - Yansheng Ye
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; ,
| | - Guohua Xu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; ,
| | - Zeting Zhang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; ,
| | - Wenwen Zheng
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; ,
| | - Xu Zhang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; ,
| | - Xin Zhou
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; ,
| | - Gary Pielak
- Department of Chemistry, Department of Biochemistry and Biophysics, and Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599
| | - Maili Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China; ,
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41
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Dajkovic A, Tesson B, Chauhan S, Courtin P, Keary R, Flores P, Marlière C, Filipe SR, Chapot-Chartier MP, Carballido-Lopez R. Hydrolysis of peptidoglycan is modulated by amidation of meso-diaminopimelic acid and Mg 2+ in Bacillus subtilis. Mol Microbiol 2017; 104:972-988. [PMID: 28317238 PMCID: PMC5485061 DOI: 10.1111/mmi.13673] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/15/2017] [Indexed: 12/27/2022]
Abstract
The ability of excess Mg2+ to compensate the absence of cell wall related genes in Bacillus subtilis has been known for a long time, but the mechanism has remained obscure. Here, we show that the rigidity of wild‐type cells remains unaffected with excess Mg2+, but the proportion of amidated meso‐diaminopimelic (mDAP) acid in their peptidoglycan (PG) is significantly reduced. We identify the amidotransferase AsnB as responsible for mDAP amidation and show that the gene encoding it is essential without added Mg2+. Growth without excess Mg2+ causes ΔasnB mutant cells to deform and ultimately lyse. In cell regions with deformations, PG insertion is orderly and indistinguishable from the wild‐type. However, PG degradation is unevenly distributed along the sidewalls. Furthermore, ΔasnB mutant cells exhibit increased sensitivity to antibiotics targeting the cell wall. These results suggest that absence of amidated mDAP causes a lethal deregulation of PG hydrolysis that can be inhibited by increased levels of Mg2+. Consistently, we find that Mg2+ inhibits autolysis of wild‐type cells. We suggest that Mg2+ helps to maintain the balance between PG synthesis and hydrolysis in cell wall mutants where this balance is perturbed in favor of increased degradation.
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Affiliation(s)
- Alex Dajkovic
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Benoit Tesson
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Smita Chauhan
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Pascal Courtin
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Ruth Keary
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | - Pierre Flores
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
| | | | - Sérgio R Filipe
- Departamento de Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, 2829-516, Portugal
| | | | - Rut Carballido-Lopez
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, Jouy-en-Josas, 78350, France
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42
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Bollschweiler D, Schaffer M, Lawrence CM, Engelhardt H. Cryo-electron microscopy of an extremely halophilic microbe: technical aspects. Extremophiles 2017; 21:393-398. [PMID: 28050645 PMCID: PMC5329092 DOI: 10.1007/s00792-016-0912-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 12/19/2016] [Indexed: 11/30/2022]
Abstract
Most halophilic Archaea of the class Halobacteriaceae depend on the presence of several molar sodium chloride for growth and cell integrity. This poses problems for structural studies, particularly for electron microscopy, where the high salt concentration results in diminished contrast. Since cryo-electron microscopy of intact cells provides new insights into the cellular and molecular organization under close-to-live conditions, we evaluated strategies and conditions to make halophilic microbes available for investigations in situ. Halobacterium salinarum, the test organism for this study, usually grows at 4.3 M NaCl. Adaptation to lower concentrations and subsequent NaCl reduction via dialysis led to still vital cells at 3 M salt. A comprehensive evaluation of vitrification parameters, thinning of frozen cells by focused-ion-beam micromachining, and cryo-electron microscopy revealed that structural studies under high salt conditions are possible in situ.
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Affiliation(s)
- Daniel Bollschweiler
- Max-Planck-Institut für Biochemie, Am Klopferspitz 18, 82152, Martinsried, Germany
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - Miroslava Schaffer
- Max-Planck-Institut für Biochemie, Am Klopferspitz 18, 82152, Martinsried, Germany
| | - C Martin Lawrence
- Max-Planck-Institut für Biochemie, Am Klopferspitz 18, 82152, Martinsried, Germany
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT, USA
| | - Harald Engelhardt
- Max-Planck-Institut für Biochemie, Am Klopferspitz 18, 82152, Martinsried, Germany.
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43
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In-Cell Solid-State NMR: An Emerging Technique for the Study of Biological Membranes. Biophys J 2016; 109:2461-2466. [PMID: 26682804 DOI: 10.1016/j.bpj.2015.10.041] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 10/20/2015] [Accepted: 10/30/2015] [Indexed: 11/22/2022] Open
Abstract
Biological molecular processes are often studied in model systems, which simplifies their inherent complexity but may cause investigators to lose sight of the effects of the molecular environment. Information obtained in this way must therefore be validated by experiments in the cell. NMR has been used to study biological cells since the early days of its development. The first NMR structural studies of a protein inside a cell (by solution-state NMR) and of a membrane protein (by solid-state NMR) were published in 2001 and 2011, respectively. More recently, dynamic nuclear polarization, which has been used to enhance the signal in solid-state NMR, has also been applied to the study of frozen cells. Much progress has been made in the past 5 years, and in this review we take stock of this new technique, which is particularly appropriate for the study of biological membranes.
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44
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Romaniuk JAH, Cegelski L. Bacterial cell wall composition and the influence of antibiotics by cell-wall and whole-cell NMR. Philos Trans R Soc Lond B Biol Sci 2016; 370:rstb.2015.0024. [PMID: 26370936 DOI: 10.1098/rstb.2015.0024] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The ability to characterize bacterial cell-wall composition and structure is crucial to understanding the function of the bacterial cell wall, determining drug modes of action and developing new-generation therapeutics. Solid-state NMR has emerged as a powerful tool to quantify chemical composition and to map cell-wall architecture in bacteria and plants, even in the context of unperturbed intact whole cells. In this review, we discuss solid-state NMR approaches to define peptidoglycan composition and to characterize the modes of action of old and new antibiotics, focusing on examples in Staphylococcus aureus. We provide perspectives regarding the selected NMR strategies as we describe the exciting and still-developing cell-wall and whole-cell NMR toolkit. We also discuss specific discoveries regarding the modes of action of vancomycin analogues, including oritavancin, and briefly address the reconsideration of the killing action of β-lactam antibiotics. In such chemical genetics approaches, there is still much to be learned from perturbations enacted by cell-wall assembly inhibitors, and solid-state NMR approaches are poised to address questions of cell-wall composition and assembly in S. aureus and other organisms.
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Affiliation(s)
- Joseph A H Romaniuk
- Department of Chemistry, Stanford University, 380 Roth Way, Stanford, CA 94305, USA
| | - Lynette Cegelski
- Department of Chemistry, Stanford University, 380 Roth Way, Stanford, CA 94305, USA
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45
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Arthur M. Regulation of Bacterial Peptidoglycan Polymerization. Trends Microbiol 2016; 24:519-521. [PMID: 27236859 DOI: 10.1016/j.tim.2016.05.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 05/17/2016] [Indexed: 10/21/2022]
Abstract
How bacterial cells control the activity of peptidoglycan polymerases has remained mysterious. Biochemical characterization of derivatives of penicillin-binding protein PBP1b that are functional in the absence of lipoprotein LpoB provides evidence for allosteric control of PBP1b glycosyltransferase activity via binding of LpoB to the PBP1b UBH1 domain.
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Affiliation(s)
- Michel Arthur
- Sorbonne Universités, UPMC Univ Paris 06, UMR_S 1138, Centre de Recherche des Cordeliers, Equipe 12, F-75006, Paris, France; INSERM, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France; Université Paris Descartes, Sorbonne Paris Cité, UMR_S 1138, Centre de Recherche des Cordeliers, F-75006, Paris, France.
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46
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Nygaard R, Romaniuk JAH, Rice DM, Cegelski L. Spectral snapshots of bacterial cell-wall composition and the influence of antibiotics by whole-cell NMR. Biophys J 2016; 108:1380-1389. [PMID: 25809251 DOI: 10.1016/j.bpj.2015.01.037] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 01/13/2015] [Indexed: 01/28/2023] Open
Abstract
Gram-positive bacteria surround themselves with a thick cell wall that is essential to cell survival and is a major target of antibiotics. Quantifying alterations in cell-wall composition are crucial to evaluating drug modes of action, particularly important for human pathogens that are now resistant to multiple antibiotics such as Staphylococcus aureus. Macromolecular and whole-cell NMR spectroscopy allowed us to observe the full panel of carbon and nitrogen pools in S. aureus cell walls and intact whole cells. We discovered that one-dimensional (13)C and (15)N NMR spectra, together with spectroscopic selections based on dipolar couplings as well as two-dimensional spin-diffusion measurements, revealed the dramatic compositional differences between intact cells and cell walls and allowed the identification of cell-wall signatures in whole-cell samples. Furthermore, the whole-cell NMR approach exhibited the sensitivity to detect distinct compositional changes due to treatment with the antibiotics fosfomycin (a cell-wall biosynthesis inhibitor) and chloramphenicol (a protein synthesis inhibitor). Whole cells treated with fosfomycin exhibited decreased peptidoglycan contributions while those treated with chloramphenicol contained a higher percentage of peptidoglycan as cytoplasmic protein content was reduced. Thus, general antibiotic modes of action can be identified by profiling the total carbon pools in intact whole cells.
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Affiliation(s)
- Rie Nygaard
- Department of Chemistry, Stanford University, Stanford, California
| | | | - David M Rice
- Department of Chemistry, Stanford University, Stanford, California
| | - Lynette Cegelski
- Department of Chemistry, Stanford University, Stanford, California.
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47
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Turapov O, Loraine J, Jenkins CH, Barthe P, McFeely D, Forti F, Ghisotti D, Hesek D, Lee M, Bottrill AR, Vollmer W, Mobashery S, Cohen-Gonsaud M, Mukamolova GV. The external PASTA domain of the essential serine/threonine protein kinase PknB regulates mycobacterial growth. Open Biol 2016; 5:150025. [PMID: 26136255 PMCID: PMC4632501 DOI: 10.1098/rsob.150025] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
PknB is an essential serine/threonine protein kinase required for mycobacterial cell division and cell-wall biosynthesis. Here we demonstrate that overexpression of the external PknB_PASTA domain in mycobacteria results in delayed regrowth, accumulation of elongated bacteria and increased sensitivity to β-lactam antibiotics. These changes are accompanied by altered production of certain enzymes involved in cell-wall biosynthesis as revealed by proteomics studies. The growth inhibition caused by overexpression of the PknB_PASTA domain is completely abolished by enhanced concentration of magnesium ions, but not muropeptides. Finally, we show that the addition of recombinant PASTA domain could prevent regrowth of Mycobacterium tuberculosis, and therefore offers an alternative opportunity to control replication of this pathogen. These results suggest that the PknB_PASTA domain is involved in regulation of peptidoglycan biosynthesis and maintenance of cell-wall architecture.
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Affiliation(s)
- Obolbek Turapov
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK
| | - Jessica Loraine
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK
| | - Christopher H Jenkins
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK
| | - Philippe Barthe
- Centre de Biochimie Structurale, CNRS UMR 5048, 29, rue de Navacelles, Montpellier 34090, France INSERM U1054, Université Montpellier I et II, Montpellier, France
| | - Daniel McFeely
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK
| | - Francesca Forti
- Dipartimento di BioScienze, Università degli Studi di Milano, Milan, Italy
| | - Daniela Ghisotti
- Dipartimento di BioScienze, Università degli Studi di Milano, Milan, Italy
| | - Dusan Hesek
- Department of Chemistry and Biochemistry, 423 Nieuwland Science Center, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Mijoon Lee
- Department of Chemistry and Biochemistry, 423 Nieuwland Science Center, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Andrew R Bottrill
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne NE2 4AX, UK
| | - Shahriar Mobashery
- Department of Chemistry and Biochemistry, 423 Nieuwland Science Center, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Martin Cohen-Gonsaud
- Centre de Biochimie Structurale, CNRS UMR 5048, 29, rue de Navacelles, Montpellier 34090, France INSERM U1054, Université Montpellier I et II, Montpellier, France
| | - Galina V Mukamolova
- Department of Infection, Immunity and Inflammation, University of Leicester, Leicester LE1 9HN, UK
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48
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Roy R, Bhagyalalitha M, Choudhury P, Dastidar P. Salt metathesis for developing injectable supramolecular metallohydrogelators as a multi-drug-self-delivery system. Chem Commun (Camb) 2016; 52:13811-13814. [DOI: 10.1039/c6cc07712a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Salt metathesis has been exploited to generate a series of non-steroidal anti-inflammatory drug (NSAID) based Zn(ii) metallohydrogels displaying both anti-inflammatory and anti-bacterial properties.
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Affiliation(s)
- Rajdip Roy
- Department of Organic Chemistry
- Indian Association for the Cultivation of Science (IACS)
- Kolkata - 700032
- India
| | - Meduri Bhagyalalitha
- Department of Organic Chemistry
- Indian Association for the Cultivation of Science (IACS)
- Kolkata - 700032
- India
| | - Pritam Choudhury
- Department of Biological Chemistry
- Indian Association for the Cultivation of Science (IACS)
- Kolkata - 700032
- India
| | - Parthasarathi Dastidar
- Department of Organic Chemistry
- Indian Association for the Cultivation of Science (IACS)
- Kolkata - 700032
- India
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49
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Pastells C, Acosta G, Pascual N, Albericio F, Royo M, Marco MP. An immunochemical strategy based on peptidoglycan synthetic peptide epitopes to diagnose Staphylococcus aureus infections. Anal Chim Acta 2015; 889:203-11. [DOI: 10.1016/j.aca.2015.07.049] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Revised: 07/07/2015] [Accepted: 07/16/2015] [Indexed: 11/24/2022]
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50
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Equilibrium binding behavior of magnesium to wall teichoic acid. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1981-7. [PMID: 25969394 DOI: 10.1016/j.bbamem.2015.05.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 04/20/2015] [Accepted: 05/06/2015] [Indexed: 11/21/2022]
Abstract
Peptidoglycan and teichoic acids are the major cell wall components of Gram-positive bacteria that obtain and sequester metal ions required for biochemical processes. The delivery of metals to the cytoplasmic membrane is aided by anionic binding sites within the peptidoglycan and along the phosphodiester polymer of teichoic acid. The interaction with metals is a delicate balance between the need for attraction and ion diffusion to the membrane. Likewise, metal chelation from the extracellular fluid must initially have strong binding energetics that weaken within the cell wall to enable ion release. We employed atomic absorption and equilibrium dialysis to measure the metal binding capacity and metal binding affinity of wall teichoic acid and Mg2+. Data show that Mg2+ binds to WTA with a 1:2Mg2+ to phosphate ratio with a binding capacity of 1.27 μmol/mg. The affinity of Mg2+ to WTA was also found to be 41×10(3) M(-1) at low metal concentrations and 1.3×10(3) M(-1) at higher Mg2+ concentrations due to weakening electrostatic effects. These values are lower than the values describing Mg2+ interactions with peptidoglycan. However, the binding capacity of WTA is 4 times larger than peptidoglycan. External WTA initially binds metals with positive cooperativity, but metal binding switches to negative cooperativity, whereas interior WTA binds metals with only negative cooperativity. The relevance of this work is to describe changes in metal binding behavior depending on environment. When metals are sparse, chelation is strong to ensure survival yet the binding weakens when essential minerals are abundant.
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