1
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Li L, Qiao Y. Opportunities in exploring chemical biology tools for better strategies against Candida albicans. Curr Opin Chem Biol 2025; 86:102595. [PMID: 40184759 DOI: 10.1016/j.cbpa.2025.102595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2024] [Revised: 03/04/2025] [Accepted: 03/08/2025] [Indexed: 04/07/2025]
Abstract
The growing global prevalence of drug-resistant fungal infections and the scarcity of effective clinical antifungal drugs necessitate an urgent need for new treatments and strategies. In the quest for novel antifungal and anti-virulence compounds and alternative drug targets in fungi, we recognize the significant value of chemical biology tools in guiding these endeavors. Focusing on Candida albicans, the major fungal pathogen in humans, this review explores recent antifungal research efforts that utilize chemical biology tools-such as chemical probes and toolkits-that offer valuable biological insights into the cellular processes of C. albicans. In addition, we discuss the wealth of compounds in the host gut microbiota that naturally influence C. albicans invasive growth in the gut habitat, presenting promising yet underexplored opportunities for developing novel antifungal and anti-virulence strategies. Chemical biology tools are uniquely positioned to unlock the potential of gut microbiota-derived molecules and metabolites in combating C. albicans infections.
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Affiliation(s)
- Lanxin Li
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technical University 637371, Singapore
| | - Yuan Qiao
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technical University 637371, Singapore.
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2
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Alamán-Zárate MG, Rady BJ, Ledermann R, Shephard N, Evans CA, Dickman MJ, Turner RD, Rifflet A, Patel AV, Gomperts Boneca I, Poole PS, Bern M, Mesnage S. A software tool and strategy for peptidoglycomics, the high-resolution analysis of bacterial peptidoglycans via LC-MS/MS. Commun Chem 2025; 8:91. [PMID: 40133660 PMCID: PMC11937551 DOI: 10.1038/s42004-025-01490-6] [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: 10/08/2024] [Accepted: 03/10/2025] [Indexed: 03/27/2025] Open
Abstract
Peptidoglycan is an essential component of the bacterial cell envelope-a mesh-like macromolecule that protects the bacterium from osmotic stress and its internal turgor pressure. The composition and architecture of peptidoglycan is heterogeneous and changes as bacteria grow, divide, and respond to their environment. Though peptidoglycan has long been studied via LC-MS/MS, the analysis of this data remains challenging as peptidoglycan's unusual composition and branching can't be handled by proteomics software. Here we describe user-friendly open-source tools and a web interface for building peptidoglycan databases, performing MS searches, and predicting the MS/MS fragmentation of muropeptides. We then use Rhizobium leguminosarum to describe a step-by-step strategy for the high-resolution analysis of peptidoglycan. The unprecedented detail of R. leguminosarum's peptidoglycan composition (>250 muropeptides) reveals even the subtlest remodelling between growth conditions. These new and easier to use tools enable more systematic analyses of peptidoglycan dynamics.
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Affiliation(s)
| | - Brooks J Rady
- Molecular Microbiology, School of Biosciences, University of Sheffield, Sheffield, UK
| | | | - Neil Shephard
- Research Software Engineer team, University of Sheffield, Sheffield, UK
| | - Caroline A Evans
- Department of Chemical and Biological Engineering, ChELSI Institute, University of Sheffield, Sheffield, UK
| | - Mark J Dickman
- Department of Chemical and Biological Engineering, ChELSI Institute, University of Sheffield, Sheffield, UK
| | - Robert D Turner
- Research Software Engineer team, University of Sheffield, Sheffield, UK
| | - Aline Rifflet
- Institut Pasteur, Université Paris Cité, INSERM U1306, CNRS UMR6047, Biology and genetics of the bacterial cell wall Unit, Paris, France
| | - Ankur V Patel
- Molecular Microbiology, School of Biosciences, University of Sheffield, Sheffield, UK
| | - Ivo Gomperts Boneca
- Institut Pasteur, Université Paris Cité, INSERM U1306, CNRS UMR6047, Biology and genetics of the bacterial cell wall Unit, Paris, France
| | | | | | - Stéphane Mesnage
- Molecular Microbiology, School of Biosciences, University of Sheffield, Sheffield, UK.
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3
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Kathayat D, Huang Y, Denis J, Rudoy B, Schwarz H, Szlechter J. LD-transpeptidase-mediated cell envelope remodeling enables developmental transitions and survival in Coxiella burnetii and Legionella pneumophila. J Bacteriol 2025; 207:e0024724. [PMID: 39846729 PMCID: PMC11841132 DOI: 10.1128/jb.00247-24] [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: 06/17/2024] [Accepted: 11/25/2024] [Indexed: 01/24/2025] Open
Abstract
Coxiella burnetii and Legionella pneumophila are two phylogenetically related bacterial pathogens that exhibit extreme intrinsic resistance when they enter into a dormancy-like state. This enables both pathogens to survive extended periods in growth-limited environments. Survival is dependent upon their ability to undergo developmental transitions into two phenotypically distinct variants, one specialized for intracellular replication and another for prolonged survival in the environment and host. We currently lack an understanding of the mechanisms that mediate these developmental transitions. Here, we performed peptidoglycan (PG) glycoproteome analysis and showed significant enrichment of PG structures catalyzed by LD-transpeptidases (LDTs) in the survival variants of C. burnetii and L. pneumophila. This is supported by the upregulation of LDTs, resulting in susceptibility to carbapenem antibiotics. Furthermore, deletion of the most upregulated LDT, lpg1386, in L. pneumophila significantly changes PG architecture, survival, and susceptibility to antibiotics. Significantly regulated by RpoS, a stationary-phase sigma factor, LDT-dependent PG remodeling is differentially activated by the host intracellular growth environment compared to axenic culture. In addition, β-barrel tethering, a newly discovered mechanism of LDT-mediated cell envelope stabilization, seems not to be specific to the survival variants. Interestingly, an outer membrane (OM) long-chain fatty acid transporter (Lpg1810) is tethered to PG in L. pneumophila. Collectively, these findings show that LDT-mediated PG remodeling is a major determinant of developmental transitions and survival in C. burnetii and L. pneumophila. Understanding this mechanism might inform new therapeutic approaches for treating chronic infections caused by these pathogens, as well as suggest new methods to decontaminate environmental reservoirs during outbreaks.IMPORTANCECoxiella burnetii and L. pneumophila cause Q Fever and Legionnaire's disease in humans, respectively. There is a lack of effective treatments for fatal chronic infections caused by these pathogens, particularly chronic Q Fever. These bacteria survive long term in nutrient-limited environments by differentiating into phenotypically distinct survival variants. Our study revealed that LDTs, a group of PG remodeling enzymes, play a prominent role in the phenotypic differentiations of these bacteria. We show that LDT-targeting carbapenems are effective against the survival variants, thus demanding the exploration of carbapenems for treating chronic infections caused by these pathogens. We report the tethering of a unique OM fatty acid transporter to PG in L. pneumophila that could indicate a novel function of tethering, that is, the uptake of nutrient substrates. Homologs of this transporter are widely present in the Methylobacteriaceae family of bacteria known to survive in water systems like Legionella, thus suggesting a potentially conserved mechanism of bacterial survival in nutrient-limited environments.
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Affiliation(s)
- Dipak Kathayat
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, USA
| | - Yujia Huang
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, USA
| | - Joee Denis
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, USA
- Department of Microbiology, Cornell University, Ithaca, New York, USA
| | - Benjamin Rudoy
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, USA
| | - Hana Schwarz
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, USA
| | - Jacob Szlechter
- Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York, USA
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4
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Hernandez-Rocamora V, Martorana AM, Belloso A, Ballesteros D, Zaccaria M, Perez AJ, Iorga BI, Abia D, Gray J, Breukink E, Xiao J, Pazos M, Polissi A, Vollmer W. A novel peptidoglycan deacetylase modulates daughter cell separation in E. coli. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.02.18.638797. [PMID: 40027703 PMCID: PMC11870482 DOI: 10.1101/2025.02.18.638797] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/05/2025]
Abstract
Peptidoglycan hydrolases facilitate bacterial cell wall growth by creating space for insertion of new material and allowing physical separation of daughter cells. In Escherichia coli, three peptidoglycan amidases, AmiA, AmiB and AmiC, cleave septal peptidoglycan during cell division. The LytM-domain proteins EnvC and NlpD activate these amidases either from inside the cell or the outer membrane: EnvC binds to the cytoplasmic membrane-anchored divisome components FtsEX, and NlpD and ActS are outer membrane lipoproteins. Here we report the identification of a novel periplasmic deacetylase called SddA that removes acetyl groups from denuded peptidoglycan glycan strands, the products of amidases. SddA is a substrate for the periplasmic protease Prc, suggesting regulation via protein degradation. The sddA gene is co-expressed with the gene encoding EnvC, linking SddA function to amidase activation. Consistent with this link, the deletion of sddA alleviates phenotypes associated with lack of amidase activation, while overexpression of sddA alleviates phenotypes related to a defective Tol-Pal system and causes cell chaining due to reduced septum peptidoglycan cleavage unless envC is co-expressed. We present a model according to which SddA modulates the activation of the septum-splitting amidases during cell division.
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Affiliation(s)
- Victor Hernandez-Rocamora
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Alessandra M Martorana
- Department of Pharmacological and Biomolecular Sciences "Rodolfo Paoletti", University of Milano, Milano, Italy
| | - Aitana Belloso
- Centro de Biología Molecular Severo Ochoa (CBM), CSIC - Universidad Autónoma de Madrid, Madrid, Spain
| | - Daniel Ballesteros
- Centro de Biología Molecular Severo Ochoa (CBM), CSIC - Universidad Autónoma de Madrid, Madrid, Spain
| | - Marta Zaccaria
- Department of Pharmacological and Biomolecular Sciences "Rodolfo Paoletti", University of Milano, Milano, Italy
| | - Amilcar J Perez
- Department of Biophysics & Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Bogdan I Iorga
- Université Paris-Saclay, CNRS, Institut de Chimie des Substances Naturelles, Gif-sur-Yvette, France
| | - David Abia
- Centro de Biología Molecular Severo Ochoa (CBM), CSIC - Universidad Autónoma de Madrid, Madrid, Spain
| | - Joe Gray
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Eefjan Breukink
- Membrane Biochemistry and Biophysics, Bijvoet Centre for Biomolecular Research, Department of Chemistry, Utrecht University, Utrecht, The Netherlands
| | - Jie Xiao
- Department of Biophysics & Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Manuel Pazos
- Centro de Biología Molecular Severo Ochoa (CBM), CSIC - Universidad Autónoma de Madrid, Madrid, Spain
- Instituto Universitario de Biología Molecular (IUBM) y Departamento de Biología Molecular, Universidad Autónoma de Madrid, Madrid, Spain
| | - Alessandra Polissi
- Department of Pharmacological and Biomolecular Sciences "Rodolfo Paoletti", University of Milano, Milano, Italy
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Biosciences Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, Australia
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5
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Awad MM, Suraweera CD, Vidor CJ, Ye-Lin AY, Williams GC, Mileto SJ, Barlow CK, McGowan S, Lyras D. A Clostridioides difficile endolysin modulates toxin secretion without cell lysis. Commun Biol 2024; 7:1044. [PMID: 39179651 PMCID: PMC11344133 DOI: 10.1038/s42003-024-06730-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 08/13/2024] [Indexed: 08/26/2024] Open
Abstract
The Clostridia produce and secrete Large Clostridial Glucosylating Toxins (LCGTs) responsible for disease symptoms, but the secretion mechanism is largely unknown. Recently, a holin-like protein was shown to be essential for toxin secretion. Holins, typically bacteriophage-specific proteins, are part of the holin-endo(lysin) system that releases phage progeny. To determine if the clostridia also use a lysin, we investigated two conserved putative lysins, M7404_01910 and M7404_02200, in the release of the LCGTs TcdA and TcdB from a Clostridioides difficile ribotype 027 strain, M7404. Sequence analysis and structural modelling indicates that both proteins are related to N-acetylmuramoyl-l-alanine amidases, similar to CD27L, a lysin from the C. difficile phage ΦCD27. Disruption of these genes reveal that only M7404_02200 contributes to toxin secretion and does so in a non-lytic fashion. Peptidoglycan hydrolysis assays show that recombinant M7404_02200 is an active peptidoglycan amidase, confirming its role in TcdA and TcdB secretion in C. difficile M7404.
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Affiliation(s)
- Milena M Awad
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, 3800, Australia
| | - Chathura D Suraweera
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, 3800, Australia
| | - Callum J Vidor
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, 3800, Australia
| | - Auberon Y Ye-Lin
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, 3800, Australia
| | - Galain C Williams
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, 3800, Australia
| | - Steven J Mileto
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, 3800, Australia
| | - Christopher K Barlow
- Department of Biochemistry, Biomedicine Discovery Institute, Monash University, Clayton, 3800, Australia
- Monash Proteomics & Metabolomics Platform, Monash University, Clayton, 3800, Australia
| | - Sheena McGowan
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, 3800, Australia
| | - Dena Lyras
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, 3800, Australia.
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6
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Wheeler R, Gomperts Boneca I. The hidden base of the iceberg: gut peptidoglycome dynamics is foundational to its influence on the host. Gut Microbes 2024; 16:2395099. [PMID: 39239828 PMCID: PMC11382707 DOI: 10.1080/19490976.2024.2395099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 07/01/2024] [Accepted: 08/16/2024] [Indexed: 09/07/2024] Open
Abstract
The intestinal microbiota of humans includes a highly diverse range of bacterial species. All these bacteria possess a cell wall, composed primarily of the macromolecule peptidoglycan. As such, the gut also harbors an abundant and varied peptidoglycome. A remarkable range of host physiological pathways are regulated by peptidoglycan fragments that originate from the gut microbiota and enter the host system. Interactions between the host system and peptidoglycan can influence physiological development and homeostasis, promote health, or contribute to inflammatory disease. Underlying these effects is the interplay between microbiota composition and enzymatic processes that shape the intestinal peptidoglycome, dictating the types of peptidoglycan generated, that subsequently cross the gut barrier. In this review, we highlight and discuss the hidden and emerging functional aspects of the microbiome, i.e. the hidden base of the iceberg, that modulate the composition of gut peptidoglycan, and how these fundamental processes are drivers of physiological outcomes for the host.
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Affiliation(s)
- Richard Wheeler
- Institut Pasteur, Université Paris Cité, Paris, France
- Hauts-de-Seine, Arthritis Research and Development, Neuilly-sur-Seine, France
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7
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Alamán-Zárate MG, Rady BJ, Evans CA, Pian B, Greetham D, Marecos-Ortiz S, Dickman MJ, Lidbury IDEA, Lovering AL, Barstow BM, Mesnage S. Unusual 1-3 peptidoglycan cross-links in Acetobacteraceae are made by L,D-transpeptidases with a catalytic domain distantly related to YkuD domains. J Biol Chem 2024; 300:105494. [PMID: 38006948 PMCID: PMC10727944 DOI: 10.1016/j.jbc.2023.105494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 11/20/2023] [Accepted: 11/20/2023] [Indexed: 11/27/2023] Open
Abstract
Peptidoglycan is an essential component of the bacterial cell envelope that contains glycan chains substituted by short peptide stems. Peptide stems are polymerized by D,D-transpeptidases, which make bonds between the amino acid in position four of a donor stem and the third residue of an acceptor stem (4-3 cross-links). Some bacterial peptidoglycans also contain 3-3 cross-links that are formed by another class of enzymes called L,D-transpeptidases which contain a YkuD catalytic domain. In this work, we investigate the formation of unusual bacterial 1-3 peptidoglycan cross-links. We describe a version of the PGFinder software that can identify 1-3 cross-links and report the high-resolution peptidoglycan structure of Gluconobacter oxydans (a model organism within the Acetobacteraceae family). We reveal that G. oxydans peptidoglycan contains peptide stems made of a single alanine as well as several dipeptide stems with unusual amino acids at their C-terminus. Using a bioinformatics approach, we identified a G. oxydans mutant from a transposon library with a drastic reduction in 1-3 cross-links. Through complementation experiments in G. oxydans and recombinant protein production in a heterologous host, we identify an L,D-transpeptidase enzyme with a domain distantly related to the YkuD domain responsible for these non-canonical reactions. This work revisits the enzymatic capabilities of L,D-transpeptidases, a versatile family of enzymes that play a key role in bacterial peptidoglycan remodelling.
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Affiliation(s)
- Marcel G Alamán-Zárate
- Molecular Microbiology, Biochemistry to Disease, School of Biosciences, University of Sheffield, Sheffield, UK
| | - Brooks J Rady
- Molecular Microbiology, Biochemistry to Disease, School of Biosciences, University of Sheffield, Sheffield, UK
| | - Caroline A Evans
- Department of Chemical and Biological Engineering, ChELSI Institute, University of Sheffield, Sheffield, UK
| | - Brooke Pian
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, USA
| | - Darren Greetham
- Molecular Microbiology, Biochemistry to Disease, School of Biosciences, University of Sheffield, Sheffield, UK
| | - Sabrina Marecos-Ortiz
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, USA
| | - Mark J Dickman
- Department of Chemical and Biological Engineering, ChELSI Institute, University of Sheffield, Sheffield, UK
| | - Ian D E A Lidbury
- Molecular Microbiology, Biochemistry to Disease, School of Biosciences, University of Sheffield, Sheffield, UK
| | | | - Buz M Barstow
- Department of Biological and Environmental Engineering, Cornell University, Ithaca, USA
| | - Stéphane Mesnage
- Molecular Microbiology, Biochemistry to Disease, School of Biosciences, University of Sheffield, Sheffield, UK.
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8
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Galley NF, Greetham D, Alamán-Zárate MG, Williamson MP, Evans CA, Spittal WD, Buddle JE, Freeman J, Davis GL, Dickman MJ, Wilcox MH, Lovering AL, Fagan RP, Mesnage S. Clostridioides difficile canonical L,D-transpeptidases catalyze a novel type of peptidoglycan cross-links and are not required for beta-lactam resistance. J Biol Chem 2024; 300:105529. [PMID: 38043796 PMCID: PMC10792238 DOI: 10.1016/j.jbc.2023.105529] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 11/19/2023] [Accepted: 11/27/2023] [Indexed: 12/05/2023] Open
Abstract
Clostridioides difficile is the leading cause of antibiotic-associated diarrhea worldwide with significant morbidity and mortality. This organism is naturally resistant to several beta-lactam antibiotics that inhibit the polymerization of peptidoglycan, an essential component of the bacteria cell envelope. Previous work has revealed that C. difficile peptidoglycan has an unusual composition. It mostly contains 3-3 cross-links, catalyzed by enzymes called L,D-transpeptidases (Ldts) that are poorly inhibited by beta-lactams. It was therefore hypothesized that peptidoglycan polymerization by these enzymes could underpin antibiotic resistance. Here, we investigated the catalytic activity of the three canonical Ldts encoded by C. difficile (LdtCd1, LdtCd2, and LdtCd3) in vitro and explored their contribution to growth and antibiotic resistance. We show that two of these enzymes catalyze the formation of novel types of peptidoglycan cross-links using meso-diaminopimelic acid both as a donor and an acceptor, also observed in peptidoglycan sacculi. We demonstrate that the simultaneous deletion of these three genes only has a minor impact on both peptidoglycan structure and resistance to beta-lactams. This unexpected result therefore implies that the formation of 3-3 peptidoglycan cross-links in C. difficile is catalyzed by as yet unidentified noncanonical Ldt enzymes.
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Affiliation(s)
- Nicola F Galley
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - Darren Greetham
- School of Biosciences, University of Sheffield, Sheffield, UK
| | | | | | - Caroline A Evans
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
| | - William D Spittal
- Department of Microbiology, Leeds Teaching Hospitals NHS Trust, Leeds Institute of Medical Research, University of Leeds, Leeds, UK; Healthcare Associated Infections Research Group, Leeds Institute of Medical Research University of Leeds, Leeds, UK
| | | | - Jane Freeman
- Department of Microbiology, Leeds Teaching Hospitals NHS Trust, Leeds Institute of Medical Research, University of Leeds, Leeds, UK; Healthcare Associated Infections Research Group, Leeds Institute of Medical Research University of Leeds, Leeds, UK
| | - Georgina L Davis
- Department of Microbiology, Leeds Teaching Hospitals NHS Trust, Leeds Institute of Medical Research, University of Leeds, Leeds, UK; Healthcare Associated Infections Research Group, Leeds Institute of Medical Research University of Leeds, Leeds, UK
| | - Mark J Dickman
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, UK
| | - Mark H Wilcox
- Department of Microbiology, Leeds Teaching Hospitals NHS Trust, Leeds Institute of Medical Research, University of Leeds, Leeds, UK; Healthcare Associated Infections Research Group, Leeds Institute of Medical Research University of Leeds, Leeds, UK
| | | | - Robert P Fagan
- School of Biosciences, University of Sheffield, Sheffield, UK
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9
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Rady BJ, Mesnage S. PGFinder, an Open-Source Software for Peptidoglycomics: The Structural Analysis of Bacterial Peptidoglycan by LC-MS. Methods Mol Biol 2024; 2836:111-132. [PMID: 38995539 DOI: 10.1007/978-1-0716-4007-4_8] [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] [Indexed: 07/13/2024]
Abstract
Peptidoglycan is a major and essential component of the bacterial cell envelope that confers cell shape and provides protection against internal osmotic pressure. This complex macromolecule is made of glycan strands cross-linked by short peptides, and its structure is continually modified throughout growth via a process referred to as "remodeling." Peptidoglycan remodeling allows cells to grow, adapt to their environment, and release fragments that can act as signaling molecules during host-pathogen interactions. Preparing peptidoglycan samples for structural analysis first requires purification of the peptidoglycan sacculus, followed by its enzymatic digestion into disaccharide peptides (muropeptides). These muropeptides can then be characterized by liquid chromatography coupled mass spectrometry (LC-MS) and used to infer the structure of intact peptidoglycan sacculi. Due to the presence of unusual crosslinks, noncanonical amino acids, and amino sugars, the analysis of peptidoglycan LC-MS datasets cannot be handled by traditional proteomics software. In this chapter, we describe a protocol to perform the analysis of peptidoglycan LC-MS datasets using the open-source software PGFinder. We provide a step-by-step strategy to deconvolute data from various mass spectrometry instruments, generate muropeptide databases, perform a PGFinder search, and process the data output.
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Affiliation(s)
- Brooks J Rady
- School of Biosciences, University of Sheffield, Sheffield, UK
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10
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Pseudomonas aeruginosa Alters Peptidoglycan Composition under Nutrient Conditions Resembling Cystic Fibrosis Lung Infections. mSystems 2022; 7:e0015622. [PMID: 35545925 PMCID: PMC9239049 DOI: 10.1128/msystems.00156-22] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Epidemic strains of Pseudomonas aeruginosa are highly virulent opportunistic pathogens with increased transmissibility and enhanced antimicrobial resistance. Understanding the cellular mechanisms behind this heightened virulence and resistance is critical. Peptidoglycan (PG) is an integral component of P. aeruginosa cells that is essential to its survival and a target for antimicrobials. Here, we examined the global PG composition of two P. aeruginosa epidemic strains, LESB58 and LESlike1, and compared them to the common laboratory strains PAO1 and PA14. We also examined changes in PG composition when the strains were cultured under nutrient conditions that resembled cystic fibrosis lung infections. We identified 448 unique muropeptides and provide the first evidence for stem peptides modified with O-methylation, meso-diaminopimelic acid (mDAP) deamination, and novel substitutions of mDAP residues within P. aeruginosa PG. Our results also present the first evidence for both d,l- and l,d-endopeptidase activity on the PG sacculus of a Gram-negative organism. The PG composition of the epidemic strains varied significantly when grown under conditions resembling cystic fibrosis (CF) lung infections, showing increases in O-methylated stem peptides and decreases in l,d-endopeptidase activity as well as an increased abundance of de-N-acetylated sugars and l,d-transpeptidase activity, which are related to bacterial virulence and antibiotic resistance, respectively. We also identified strain-specific changes where LESlike1 increased the addition of unique amino acids to the terminus of the stem peptide and LESB58 increased amidase activity. Overall, this study demonstrates that P. aeruginosa PG composition is primarily influenced by nutrient conditions that mimic the CF lung; however, inherent strain-to-strain differences also exist. IMPORTANCE Using peptidoglycomics to examine the global composition of the peptidoglycan (PG) allows insights into the enzymatic activity that functions on this important biopolymer. Changes within the PG structure have implications for numerous physiological processes, including virulence and antimicrobial resistance. The identification of highly unique PG modifications illustrates the complexity of this biopolymer in Pseudomonas aeruginosa. Analyzing the PG composition of clinical P. aeruginosa epidemic strains provides insights into the increased virulence and antimicrobial resistance of these difficult-to-eradicate infections.
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11
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Arenas T, Osorio A, Ginez LD, Camarena L, Poggio S. Bacterial cell-wall quantification by a modified low volume Nelson-Somogyi method and its use with different sugars. Can J Microbiol 2022; 68:295-302. [PMID: 35100051 DOI: 10.1139/cjm-2021-0238] [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]
Abstract
The study of peptidoglycan binding proteins frequently requires in vitro binding assays in which the isolated peptidoglycan used as substrate has to be carefully quantified. Here we describe an easy and sensitive assay for the quantification of peptidoglycan based on a modified Nelson-Somogyi reducing sugar assay. We report the response of this assay to different common sugars and adapt its use to peptidoglycan samples that have been subjected to acid hydrolysis. This method showed a better sensitivity than the peptidoglycan quantification method based on the acid detection of diaminopimelic acid. The method described in this work besides being valuable in the characterization of peptidoglycan binding proteins, is also useful for quantification of reducing monosaccharides or of polysaccharides after acid or hydrolysis.
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Affiliation(s)
- Thelma Arenas
- Universidad Nacional Autónoma de México, 7180, Depto. Biología Molecular y Biotecnología, Ciudad de Mexico, Mexico;
| | - Aurora Osorio
- Universidad Nacional Autónoma de México, 7180, Depto. Biología Molecular y Biotecnología, Ciudad de Mexico, Mexico;
| | - Luis David Ginez
- National Autonomous University of Mexico, 7180, Molecular Biology and Biotechnology, Ciudad de Mexico, Mexico, 04510;
| | - Laura Camarena
- Universidad Nacional Autonoma de Mexico, 7180, Instituto de Investigaciones Biomédicas, Ciudad de Mexico, Ciudad de México, Mexico;
| | - Sebastian Poggio
- Universidad Nacional Autonoma de Mexico Instituto de Investigaciones Biomedicas, 61738, Biologia Molecular y Biotecnologia, Ciudad de Mexico, Ciudad de Mexico, Mexico;
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