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Kelly SD, Williams DM, Zhu S, Kim T, Jana M, Nothof J, Thota VN, Lowary TL, Whitfield C. Klebsiella pneumoniae O-polysaccharide biosynthesis highlights the diverse organization of catalytic modules in ABC transporter-dependent glycan assembly. J Biol Chem 2024; 300:107420. [PMID: 38815868 PMCID: PMC11231755 DOI: 10.1016/j.jbc.2024.107420] [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: 04/12/2024] [Revised: 05/10/2024] [Accepted: 05/19/2024] [Indexed: 06/01/2024] Open
Abstract
Klebsiella pneumoniae provides influential prototypes for lipopolysaccharide O antigen (OPS) biosynthesis in Gram-negative bacteria. Sequences of OPS-biosynthesis gene clusters in serotypes O4 and O7 suggest fundamental differences in the organization of required enzyme modules compared to other serotypes. Furthermore, some required activities were not assigned by homology shared with characterized enzymes. The goal of this study was therefore to resolve the serotype O4 and O7 pathways to expand our broader understanding of glycan polymerization and chain termination processes. The O4 and O7 antigens were produced from cloned genetic loci in recombinant Escherichia coli. Systematic in vivo and in vitro approaches were then applied to assign each enzyme in each of the pathways, defining the necessary components for polymerization and chain termination. OPS assembly is accomplished by multiprotein complexes formed by interactions between polymerase components variably distributed in single and multimodule proteins. In each complex, a terminator function is present in a protein containing a characteristic coiled-coil molecular ruler, which determines glycan chain length. In serotype O4, we discovered a CMP-α-3-deoxy-ᴅ-manno-octulosonic acid-dependent chain-terminating glycosyltransferase that is the founding member of a new glycosyltransferase family (GT137) and potentially identifies a new glycosyltransferase fold. The O7 OPS is terminated by a methylphosphate moiety, like the K. pneumoniae O3 antigen, but the methyltransferase-kinase enzyme pairs responsible for termination in these serotypes differ in sequence and predicted structures. Together, the characterization of O4 and O7 has established unique enzyme activities and provided new insight into glycan-assembly strategies that are widely distributed in bacteria.
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Affiliation(s)
- Steven D Kelly
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Danielle M Williams
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Shawna Zhu
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Taeok Kim
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Manas Jana
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | - Jeremy Nothof
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada
| | | | - Todd L Lowary
- Department of Chemistry, University of Alberta, Edmonton, Alberta, Canada; Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan; Institute of Biochemical Sciences, National Taiwan University, Taipei, Taiwan.
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada.
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2
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Kelly SD, Ovchinnikova OG, Müller F, Steffen M, Braun M, Sweeney RP, Kowarik M, Follador R, Lowary TL, Serventi F, Whitfield C. Identification of a second glycoform of the clinically prevalent O1 antigen from Klebsiella pneumoniae. Proc Natl Acad Sci U S A 2023; 120:e2301302120. [PMID: 37428935 PMCID: PMC10629545 DOI: 10.1073/pnas.2301302120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 05/15/2023] [Indexed: 07/12/2023] Open
Abstract
Carbapenemase and extended β-lactamase-producing Klebsiella pneumoniae isolates represent a major health threat, stimulating increasing interest in immunotherapeutic approaches for combating Klebsiella infections. Lipopolysaccharide O antigen polysaccharides offer viable targets for immunotherapeutic development, and several studies have described protection with O-specific antibodies in animal models of infection. O1 antigen is produced by almost half of clinical Klebsiella isolates. The O1 polysaccharide backbone structure is known, but monoclonal antibodies raised against the O1 antigen showed varying reactivity against different isolates that could not be explained by the known structure. Reinvestigation of the structure by NMR spectroscopy revealed the presence of the reported polysaccharide backbone (glycoform O1a), as well as a previously unknown O1b glycoform composed of the O1a backbone modified with a terminal pyruvate group. The activity of the responsible pyruvyltransferase (WbbZ) was confirmed by western immunoblotting and in vitro chemoenzymatic synthesis of the O1b terminus. Bioinformatic data indicate that almost all O1 isolates possess genes required to produce both glycoforms. We describe the presence of O1ab-biosynthesis genes in other bacterial species and report a functional O1 locus on a bacteriophage genome. Homologs of wbbZ are widespread in genetic loci for the assembly of unrelated glycostructures in bacteria and yeast. In K. pneumoniae, simultaneous production of both O1 glycoforms is enabled by the lack of specificity of the ABC transporter that exports the nascent glycan, and the data reported here provide mechanistic understanding of the capacity for evolution of antigenic diversity within an important class of biomolecules produced by many bacteria.
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Affiliation(s)
- Steven D. Kelly
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ONN1G 2W1, Canada
| | - Olga G. Ovchinnikova
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ONN1G 2W1, Canada
| | | | | | - Martin Braun
- LimmaTech Biologics AG, Schlieren8952, Switzerland
| | - Ryan P. Sweeney
- Department of Chemistry, University of Alberta, Edmonton, ABT6G 2G2, Canada
| | | | | | - Todd L. Lowary
- Department of Chemistry, University of Alberta, Edmonton, ABT6G 2G2, Canada
- Institute of Biological Chemistry, Academia Sinica, Taipei, Nangang11529, Taiwan
- Institute of Biochemical Sciences, National Taiwan University, Taipei10617, Taiwan
| | | | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ONN1G 2W1, Canada
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3
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Luong P, Dube DH. Dismantling the bacterial glycocalyx: Chemical tools to probe, perturb, and image bacterial glycans. Bioorg Med Chem 2021; 42:116268. [PMID: 34130219 DOI: 10.1016/j.bmc.2021.116268] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 05/27/2021] [Accepted: 06/01/2021] [Indexed: 12/20/2022]
Abstract
The bacterial glycocalyx is a quintessential drug target comprised of structurally distinct glycans. Bacterial glycans bear unusual monosaccharide building blocks whose proper construction is critical for bacterial fitness, survival, and colonization in the human host. Despite their appeal as therapeutic targets, bacterial glycans are difficult to study due to the presence of rare bacterial monosaccharides that are linked and modified in atypical manners. Their structural complexity ultimately hampers their analytical characterization. This review highlights recent advances in bacterial chemical glycobiology and focuses on the development of chemical tools to probe, perturb, and image bacterial glycans and their biosynthesis. Current technologies have enabled the study of bacterial glycosylation machinery even in the absence of detailed structural information.
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Affiliation(s)
- Phuong Luong
- Department of Chemistry & Biochemistry, Bowdoin College, 6600 College Station, Brunswick, ME 04011, USA
| | - Danielle H Dube
- Department of Chemistry & Biochemistry, Bowdoin College, 6600 College Station, Brunswick, ME 04011, USA.
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4
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Kocev A, Melamed J, Torgov V, Danilov L, Veselovsky V, Brockhausen I. The wclY gene of Escherichia coli serotype O117 encodes an α1,4-glucosyltransferase with strict acceptor specificity but broad donor specificity. Glycobiology 2020; 30:9003-9014. [PMID: 32421169 DOI: 10.1093/glycob/cwaa045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 11/14/2022] Open
Abstract
The O antigen of enterotoxigenic Escherichia coli serotype O117 consists of repeating units with the structure [-D-GalNAcβ1-3-L-Rhaα1-4-D-Glcα1-4-D-Galβ1-3-D-GalNAcα1-4]n. A related structure is found in E. coli O107 where Glc is replaced by a GlcNAc residue. The O117 and O107 antigen biosynthesis gene clusters are homologous and reveal the presence of four putative glycosyltransferase (GT) genes, wclW, wclX, wclY and wclZ, but the enzymes have not yet been biochemically characterized. We show here that the His6-tagged WclY protein expressed in E. coli Lemo21(DE3) cells is an α1,4-Glc-transferase that transfers Glc to the Gal moiety of Galβ1-3GalNAcα-OPO3-PO3-phenoxyundecyl as a specific acceptor and that the diphosphate moiety of this acceptor is required. WclY utilized UDP-Glc, TDP-Glc, ADP-Glc, as well as UDP-GlcNAc, UDP-Gal or UDP-GalNAc as donor substrates, suggesting an unusual broad donor specificity. Activity using GDP-Man suggested the presence of a novel Man-transferase in Lemo21(DE3) cells. Mutations of WclY revealed that both Glu residues of the Ex7E motif within the predicted GT domain are essential for activity. High GlcNAc-transferase (GlcNAc-T) activities of WclY were created by mutating Arg194 to Cys. A triple mutant identical to WclY in E. coli O107 was identified as an α1,4 GlcNAc-T. The characterization of WclY opens the door for the development of antibacterial approaches.
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Affiliation(s)
- Alexander Kocev
- Department of Biomedical and Molecular Sciences, Queen's University, 18 Stuart St., Kingston, ON K7L3N6, Canada
| | - Jacob Melamed
- Department of Biomedical and Molecular Sciences, Queen's University, 18 Stuart St., Kingston, ON K7L3N6, Canada
| | - Vladimir Torgov
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, Moscow, Russia
| | - Leonid Danilov
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, Moscow, Russia
| | - Vladimir Veselovsky
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, Moscow, Russia
| | - Inka Brockhausen
- Department of Biomedical and Molecular Sciences, Queen's University, 18 Stuart St., Kingston, ON K7L3N6, Canada
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5
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Liu B, Furevi A, Perepelov AV, Guo X, Cao H, Wang Q, Reeves PR, Knirel YA, Wang L, Widmalm G. Structure and genetics of Escherichia coli O antigens. FEMS Microbiol Rev 2020; 44:655-683. [PMID: 31778182 PMCID: PMC7685785 DOI: 10.1093/femsre/fuz028] [Citation(s) in RCA: 121] [Impact Index Per Article: 30.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 11/22/2019] [Indexed: 02/07/2023] Open
Abstract
Escherichia coli includes clonal groups of both commensal and pathogenic strains, with some of the latter causing serious infectious diseases. O antigen variation is current standard in defining strains for taxonomy and epidemiology, providing the basis for many serotyping schemes for Gram-negative bacteria. This review covers the diversity in E. coli O antigen structures and gene clusters, and the genetic basis for the structural diversity. Of the 187 formally defined O antigens, six (O31, O47, O67, O72, O94 and O122) have since been removed and three (O34, O89 and O144) strains do not produce any O antigen. Therefore, structures are presented for 176 of the 181 E. coli O antigens, some of which include subgroups. Most (93%) of these O antigens are synthesized via the Wzx/Wzy pathway, 11 via the ABC transporter pathway, with O20, O57 and O60 still uncharacterized due to failure to find their O antigen gene clusters. Biosynthetic pathways are given for 38 of the 49 sugars found in E. coli O antigens, and several pairs or groups of the E. coli antigens that have related structures show close relationships of the O antigen gene clusters within clades, thereby highlighting the genetic basis of the evolution of diversity.
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Affiliation(s)
- Bin Liu
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjing 300457, China
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, 23 Hongda Street, TEDA, Tianjin 300457, China
- Tianjin Key Laboratory of Microbial Functional Genomics, 23 Hongda Street, TEDA, Tianjin 300457, China
| | - Axel Furevi
- Department of Organic Chemistry, Arrhenius Laboratory, Svante Arrhenius väg 16C, Stockholm University, S-106 91 Stockholm, Sweden
| | - Andrei V Perepelov
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect, 47, Moscow, Russia
| | - Xi Guo
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjing 300457, China
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, 23 Hongda Street, TEDA, Tianjin 300457, China
- Tianjin Key Laboratory of Microbial Functional Genomics, 23 Hongda Street, TEDA, Tianjin 300457, China
| | - Hengchun Cao
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjing 300457, China
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, 23 Hongda Street, TEDA, Tianjin 300457, China
- Tianjin Key Laboratory of Microbial Functional Genomics, 23 Hongda Street, TEDA, Tianjin 300457, China
| | - Quan Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjing 300457, China
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, 23 Hongda Street, TEDA, Tianjin 300457, China
- Tianjin Key Laboratory of Microbial Functional Genomics, 23 Hongda Street, TEDA, Tianjin 300457, China
| | - Peter R Reeves
- School of Molecular and Microbial Bioscience, University of Sydney, 2 Butilin Ave, Darlington NSW 2008, Sydney, Australia
| | - Yuriy A Knirel
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospect, 47, Moscow, Russia
| | - Lei Wang
- TEDA Institute of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjing 300457, China
- The Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, 23 Hongda Street, TEDA, Tianjin 300457, China
- Tianjin Key Laboratory of Microbial Functional Genomics, 23 Hongda Street, TEDA, Tianjin 300457, China
| | - Göran Widmalm
- Department of Organic Chemistry, Arrhenius Laboratory, Svante Arrhenius väg 16C, Stockholm University, S-106 91 Stockholm, Sweden
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Whitfield C, Williams DM, Kelly SD. Lipopolysaccharide O-antigens-bacterial glycans made to measure. J Biol Chem 2020; 295:10593-10609. [PMID: 32424042 DOI: 10.1074/jbc.rev120.009402] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/17/2020] [Indexed: 01/05/2023] Open
Abstract
Lipopolysaccharides are critical components of bacterial outer membranes. The more conserved lipid A part of the lipopolysaccharide molecule is a major element in the permeability barrier imposed by the outer membrane and offers a pathogen-associated molecular pattern recognized by innate immune systems. In contrast, the long-chain O-antigen polysaccharide (O-PS) shows remarkable structural diversity and fulfills a range of functions, depending on bacterial lifestyles. O-PS production is vital for the success of clinically important Gram-negative pathogens. The biological properties and functions of O-PSs are mostly independent of specific structures, but the size distribution of O-PS chains is particularly important in many contexts. Despite the vast O-PS chemical diversity, most are produced in bacterial cells by two assembly strategies, and the different mechanisms employed in these pathways to regulate chain-length distribution are emerging. Here, we review our current understanding of the mechanisms involved in regulating O-PS chain-length distribution and discuss their impact on microbial cell biology.
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Affiliation(s)
- Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Danielle M Williams
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Steven D Kelly
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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7
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Li Y, Huang J, Wang X, Xu C, Han T, Guo X. Genetic Characterization of the O-Antigen and Development of a Molecular Serotyping Scheme for Enterobacter cloacae. Front Microbiol 2020; 11:727. [PMID: 32411106 PMCID: PMC7198725 DOI: 10.3389/fmicb.2020.00727] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 03/27/2020] [Indexed: 11/13/2022] Open
Abstract
Enterobacter cloacae is a well-characterized opportunistic pathogen that is closely associated with various nosocomial infections. The O-antigen, which is one of the most variable constituents on the cell surface, has been used widely and traditionally for serological classification of many gram-negative bacteria. E. cloacae is divided into 30 serotypes, based on its O-antigen diversity. In this study, by using genomic and comparative-genomic approaches, we analyzed the O-antigen gene clusters of 26 E. cloacae serotypes in depth. We also identified the sero-specific gene for each serotype and developed a multiplex polymerase chain reaction (PCR) method. The sensitivity of the assay was 0.1 ng for genomic DNA and 103 colony forming units for pure cultures. The assay reliability was evaluated by double-blinded testing with 81 clinical strains. Furthermore, we established a valid, genome-based tool for in silico serotyping of E. cloacae. By screening 431 E. cloacae genomes deposited in GenBank, 304 were classified into current antigenic scheme, and 112 were allocated into 55 putative novel serotypes. Our results represent the first genetic basis of the O-antigen diversity and variation of E. cloacae, providing a rationale for studying the O-antigen associated evolution and pathogenesis of this bacterium. In addition, we extended the current serotyping system for E. cloacae, which is important for detection and epidemiological surveillance purposes for this important pathogen.
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Affiliation(s)
- Yayue Li
- The Third Central Hospital of Tianjin, Tianjin Key Laboratory of Extracorporeal Life Support for Critical Diseases, Tianjin Institute of Hepatobiliary Disease, Tianjin, China
| | - Junjie Huang
- Department of Vascular Surgery, Tianjin Hospital, Tianjin, China
| | - Xiaotong Wang
- Tianjin Children's Hospital, Third Central Clinical College of Tianjin Medical University, Tianjin, China
| | - Cong Xu
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
| | - Tao Han
- The Third Central Hospital of Tianjin, Tianjin Key Laboratory of Extracorporeal Life Support for Critical Diseases, Tianjin Institute of Hepatobiliary Disease, Tianjin, China
| | - Xi Guo
- Key Laboratory of Molecular Microbiology and Technology, Ministry of Education, TEDA Institute of Biological Sciences and Biotechnology, Nankai University, Tianjin, China
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8
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Complete Genome Sequence of a Novel Bioflocculant-Producing Strain, Microbacterium paludicola CC3. GENOME ANNOUNCEMENTS 2017; 5:5/38/e01008-17. [PMID: 28935746 PMCID: PMC5609425 DOI: 10.1128/genomea.01008-17] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Microbacterium paludicola CC3 exhibits the capability to produce polysaccharide bioflocculants. Here, we report the whole-genome sequence of M. paludicola CC3, which may be helpful in understanding the genetic basis of the biosynthesis of polysaccharide bioflocculants as well as in promoting its production and application in industrial fields.
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9
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Discovery of monoclonal antibodies cross-reactive to novel subserotypes of K. pneumoniae O3. Sci Rep 2017; 7:6635. [PMID: 28747785 PMCID: PMC5529442 DOI: 10.1038/s41598-017-06682-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 06/16/2017] [Indexed: 01/15/2023] Open
Abstract
Klebsiella pneumoniae is responsible for nosocomial infections causing significant morbidity and mortality. Treatment of newly emerging multi-drug resistant strains is hampered due to severely limited antibiotic choices. Passive immunization targeting LPS O-antigens has been proposed as an alternative therapeutic option, given the limited variability of Klebsiella O-antigens. Here we report that the O3 serogroup, previously considered to have uniform O-antigen built of mannan, represents three different subtypes differing in the number of mannose residues within the O-antigen repeating units. Genetic analysis of the genes encoding mannose polymerization revealed differences that underline the observed structural alterations. The O3 variants represent antigenically different types based on the different reactivity pattern of murine monoclonal antibodies raised against a K. pneumoniae O3 strain. Typing of a collection of K. pneumoniae O3 clinical isolates showed that strains expressing the novel O3b antigen, the tri-mannose form, were more prevalent than those having the penta-mannose form, traditionally called O3, while the tetra-mannose variant, termed here O3a, seems to be rare. A monoclonal antibody cross-reacting with all three O3 sub-serogroups was also selected and shown to bind to the surface of various K. pneumoniae strains expressing different O3 subtypes and capsular antigens.
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10
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Abstract
Uropathogenic Escherichia coli (UPEC) are opportunistic human pathogens that primarily circulate as part of commensal intestinal microbiota. Though they have the ability to survive and proliferate in various urinary tract compartments, the urinary tract is a transient, occasional habitat for UPEC. Because of this, most of the UPEC traits have originally evolved to serve in intestinal colonization and transmission. Some of these bacterial traits serve as virulence factors - they are critical to or assist in survival of UPEC as pathogens, and the structure and/or function may be specialized for the infection. Other traits could serve as anti-virulence factors - they represent liability in the urinary tract and are under selection to be lost or inactivated during the infection. Inactivation, variation, or other changes of the bacterial genes that increase the pathogen's fitness during the infection are called pathoadaptive mutations. This chapter describes examples of pathoadaptive mutations in UPEC and provides rationale for their further in-depth study.
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Robins-Browne RM, Holt KE, Ingle DJ, Hocking DM, Yang J, Tauschek M. Are Escherichia coli Pathotypes Still Relevant in the Era of Whole-Genome Sequencing? Front Cell Infect Microbiol 2016; 6:141. [PMID: 27917373 PMCID: PMC5114240 DOI: 10.3389/fcimb.2016.00141] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 10/13/2016] [Indexed: 12/15/2022] Open
Abstract
The empirical and pragmatic nature of diagnostic microbiology has given rise to several different schemes to subtype E.coli, including biotyping, serotyping, and pathotyping. These schemes have proved invaluable in identifying and tracking outbreaks, and for prognostication in individual cases of infection, but they are imprecise and potentially misleading due to the malleability and continuous evolution of E. coli. Whole genome sequencing can be used to accurately determine E. coli subtypes that are based on allelic variation or differences in gene content, such as serotyping and pathotyping. Whole genome sequencing also provides information about single nucleotide polymorphisms in the core genome of E. coli, which form the basis of sequence typing, and is more reliable than other systems for tracking the evolution and spread of individual strains. A typing scheme for E. coli based on genome sequences that includes elements of both the core and accessory genomes, should reduce typing anomalies and promote understanding of how different varieties of E. coli spread and cause disease. Such a scheme could also define pathotypes more precisely than current methods.
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Affiliation(s)
- Roy M Robins-Browne
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of MelbourneParkville, VIC, Australia; Murdoch Childrens Research Institute, Royal Children's HospitalParkville, VIC, Australia
| | - Kathryn E Holt
- Centre for Systems Genomics, The University of MelbourneParkville, VIC, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of MelbourneParkville, VIC, Australia
| | - Danielle J Ingle
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of MelbourneParkville, VIC, Australia; Centre for Systems Genomics, The University of MelbourneParkville, VIC, Australia; Department of Biochemistry and Molecular Biology, Bio21 Molecular Science and Biotechnology Institute, The University of MelbourneParkville, VIC, Australia
| | - Dianna M Hocking
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne Parkville, VIC, Australia
| | - Ji Yang
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne Parkville, VIC, Australia
| | - Marija Tauschek
- Department of Microbiology and Immunology, Peter Doherty Institute for Infection and Immunity, The University of Melbourne Parkville, VIC, Australia
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12
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Emergence of a Multidrug-Resistant Shiga Toxin-Producing Enterotoxigenic Escherichia coli Lineage in Diseased Swine in Japan. J Clin Microbiol 2016; 54:1074-81. [PMID: 26865687 DOI: 10.1128/jcm.03141-15] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Accepted: 01/30/2016] [Indexed: 01/30/2023] Open
Abstract
EnterotoxigenicEscherichia coli(ETEC) and Shiga toxin-producingE. coli(STEC) are important causes of diarrhea and edema disease in swine. The majority of swine-pathogenicE. colistrains belong to a limited range of O serogroups, including O8, O138, O139, O141, O147, O149, and O157, which are the most frequently reported strains worldwide. However, the circumstances of ETEC and STEC infections in Japan remain unknown; there have been few reports on the prevalence or characterization of swine-pathogenicE. coli In the present study, we determined the O serogroups of 967E. coliisolates collected between 1991 and 2014 from diseased swine in Japan, and we found that O139, O149, O116, and OSB9 (O serogroup ofShigella boydiitype 9) were the predominant serogroups. We further analyzed these four O serogroups using pulsed-field gel electrophoresis (PFGE), multilocus sequence typing, and virulence factor profiling. Most of the O139 and O149 strains formed serogroup-specific PFGE clusters (clusters I and II, respectively), whereas the O116 and OSB9 strains were grouped together in the same cluster (cluster III). All of the cluster III strains belonged to a single sequence type (ST88) and carried genes encoding both enterotoxin and Shiga toxin. This PFGE cluster III/ST88 lineage exhibited a high level of multidrug resistance (to a median of 10 antimicrobials). Notably, these bacteria were resistant to fluoroquinolones. Thus, this lineage should be considered a significant risk to animal production due to the toxigenicity and antimicrobial resistance of these bacteria.
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13
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Cooper CA, Mainprize IL, Nickerson NN. Genetic, Biochemical, and Structural Analyses of Bacterial Surface Polysaccharides. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2015; 883:295-315. [PMID: 26621474 DOI: 10.1007/978-3-319-23603-2_16] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Surface polysaccharides are an often essential component of the outer surface of bacteria. They may serve to protect organisms from harsh environmental conditions and to increase virulence. The focus of this review will be to introduce polysaccharide biosynthesis and export from the cell, and the associated techniques used to determine these glycostructures. Protein interactions and proteomics will then be discussed while introducing systems biology approaches used to determine protein-protein and protein-polysaccharide interactions. The final section will address related screening methods used to study gene regulation in bacteria relating to polysaccharide gene clusters and their associated regulators. The goal of this review will be to highlight key studies that have increased our knowledge of glycobiology and discuss novel methods that examine this field at the cellular level using systems biology.
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Affiliation(s)
- Colin A Cooper
- Agriculture and Food Laboratory, Laboratory Services, University of Guelph, 95 Stone Rd. W., Guelph, ON, N1H 8J7, Canada.
| | - Iain L Mainprize
- Department of Molecular and Cellular Biology, University of Guelph, 95 Stone Road, Guelph, ON, N1H 8J7, Canada
| | - Nicholas N Nickerson
- Department of Molecular and Cellular Biology, University of Guelph, 95 Stone Road, Guelph, ON, N1H 8J7, Canada.,Department of Infectious Diseases, Genentech Inc., South San Francisco, CA, 94080, USA
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14
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Liston SD, Clarke BR, Greenfield LK, Richards MR, Lowary TL, Whitfield C. Domain interactions control complex formation and polymerase specificity in the biosynthesis of the Escherichia coli O9a antigen. J Biol Chem 2014; 290:1075-85. [PMID: 25422321 DOI: 10.1074/jbc.m114.622480] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Escherichia coli O9a O-polysaccharide (O-PS) is a prototype for bacterial glycan synthesis and export by an ATP-binding cassette transporter-dependent pathway. The O9a O-PS possesses a tetrasaccharide repeat unit comprising two α-(1→2)- and two α-(1→3)-linked mannose residues and is extended on a polyisoprenoid lipid carrier by the action of a polymerase (WbdA) containing two glycosyltransferase active sites. The N-terminal domain of WbdA possesses α-(1→2)-mannosyltransferase activity, and we demonstrate in this study that the C-terminal domain is an α-(1→3)-mannosyltransferase. Previous studies established that the size of the O9a polysaccharide is determined by the chain-terminating dual kinase/methyltransferase (WbdD) that is tethered to the membrane and recruits WbdA into an active enzyme complex by protein-protein interactions. Here, we used bacterial two-hybrid analysis to identify a surface-exposed α-helix in the C-terminal mannosyltransferase domain of WbdA as the site of interaction with WbdD. However, the C-terminal domain was unable to interact with WbdD in the absence of its N-terminal partner. Through deletion analysis, we demonstrated that the α-(1→2)-mannosyltransferase activity of the N-terminal domain is regulated by the activity of the C-terminal α-(1→3)-mannosyltransferase. In mutants where the C-terminal catalytic site was deleted but the WbdD-interaction site remained, the N-terminal mannosyltransferase became an unrestricted polymerase, creating a novel polymer comprising only α-(1→2)-linked mannose residues. The WbdD protein therefore orchestrates critical localization and coordination of activities involved in chain extension and termination. Complex domain interactions are needed to position the polymerase components appropriately for assembly into a functional complex located at the cytoplasmic membrane.
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Affiliation(s)
- Sean D Liston
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1 and
| | - Bradley R Clarke
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1 and
| | - Laura K Greenfield
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1 and
| | - Michele R Richards
- the Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Todd L Lowary
- the Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Chris Whitfield
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1 and
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15
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Structural studies and biosynthetic aspects of the O-antigen polysaccharide from Escherichia coli O42. Carbohydr Res 2014; 403:174-81. [PMID: 24909379 DOI: 10.1016/j.carres.2014.05.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Revised: 05/06/2014] [Accepted: 05/10/2014] [Indexed: 01/31/2023]
Abstract
The structure of the O-antigen polysaccharide (PS) from Escherichia coli O42 has been investigated by NMR spectroscopy as the main method, which was complemented with sugar analysis, mass spectrometry, and analysis of biosynthetic information. The O-specific chain of the O-deacylated lipopolysaccharide (LPS-OH) consists of branched tetrasaccharide-glycerol repeating units joined by phosphodiester linkages. The lipid-free polysaccharide contains 0.8equiv of O-acetyl groups per repeating unit and has the following teichoic acid-like structure: Based on biosynthetic aspects, this should also be the biological repeating unit. This O-antigen structure is remarkably similar to that of E. coli O28ac, differing only in the presence or absence, respectively, of a glucose residue at the branching point. The structural similarity explains the serological cross-reactivity observed between strains of these two serogroups, and also their almost identical O-antigen gene cluster sequences.
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16
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Greenfield LK, Richards MR, Vinogradov E, Wakarchuk WW, Lowary TL, Whitfield C. Domain organization of the polymerizing mannosyltransferases involved in synthesis of the Escherichia coli O8 and O9a lipopolysaccharide O-antigens. J Biol Chem 2012; 287:38135-49. [PMID: 22989876 PMCID: PMC3488083 DOI: 10.1074/jbc.m112.412577] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2012] [Revised: 09/16/2012] [Indexed: 11/06/2022] Open
Abstract
The Escherichia coli O9a and O8 polymannose O-polysaccharides (O-PSs) serve as model systems for the biosynthesis of bacterial polysaccharides by ATP-binding cassette transporter-dependent pathways. Both O-PSs contain a conserved primer-adaptor domain at the reducing terminus and a serotype-specific repeat unit domain. The repeat unit domain is polymerized by the serotype-specific WbdA mannosyltransferase. In serotype O9a, WbdA is a bifunctional α-(1→2)-, α-(1→3)-mannosyltransferase, and its counterpart in serotype O8 is trifunctional (α-(1→2), α-(1→3), and β-(1→2)). Little is known about the detailed structures or mechanisms of action of the WbdA polymerases, and here we establish that they are multidomain enzymes. WbdA(O9a) contains two separable and functionally active domains, whereas WbdA(O8) possesses three. In WbdC(O9a) and WbdB(O9a), substitution of the first Glu of the EX(7)E motif had detrimental effects on the enzyme activity, whereas substitution of the second had no significant effect on activity in vivo. Mutation of the Glu residues in the EX(7)E motif of the N-terminal WbdA(O9a) domain resulted in WbdA variants unable to synthesize O-PS. In contrast, mutation of the Glu residues in the motif of the C-terminal WbdA(O9a) domain generated an enzyme capable of synthesizing an altered O-PS repeat unit consisting of only α-(1→2) linkages. In vitro assays with synthetic acceptors unequivocally confirmed that the N-terminal domain of WbdA(O9a) possesses α-(1→2)-mannosyltransferase activity. Together, these studies form a framework for detailed structure-function studies on individual domains and a strategy applicable for dissection and analysis of other multidomain glycosyltransferases.
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Affiliation(s)
- Laura K. Greenfield
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1
| | - Michele R. Richards
- the Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, and
| | - Evgeny Vinogradov
- the Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada
| | - Warren W. Wakarchuk
- the Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada
| | - Todd L. Lowary
- the Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, and
| | - Chris Whitfield
- From the Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1
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17
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Greenfield LK, Richards MR, Li J, Wakarchuk WW, Lowary TL, Whitfield C. Biosynthesis of the polymannose lipopolysaccharide O-antigens from Escherichia coli serotypes O8 and O9a requires a unique combination of single- and multiple-active site mannosyltransferases. J Biol Chem 2012; 287:35078-35091. [PMID: 22875852 DOI: 10.1074/jbc.m112.401000] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Escherichia coli O9a and O8 O-antigen serotypes represent model systems for the ABC transporter-dependent synthesis of bacterial polysaccharides. The O9a and O8 antigens are linear mannose homopolymers containing conserved reducing termini (the primer-adaptor), a serotype-specific repeat unit domain, and a terminator. Synthesis of these glycans occurs on the polyisoprenoid lipid-linked primer, undecaprenol pyrophosphoryl-GlcpNAc, by two conserved mannosyltransferases, WbdC and WbdB, and a serotype-specific mannosyltransferase, WbdA. The glycan structure and pattern of conservation in the O9a and O8 mannosyltransferases are not consistent with the existing model of O9a biosynthesis. Here we establish a revised pathway using a combination of in vivo (mutant complementation) experiments and in vitro strategies with purified enzymes and synthetic acceptors. WbdC and WbdB synthesize the adaptor region, where they transfer one and two α-(1→3)-linked mannose residues, respectively. The WbdA enzymes are solely responsible for forming the repeat unit domains of these O-antigens. WbdA(O9a) has two predicted active sites and polymerizes a tetrasaccharide repeat unit containing two α-(1→3)- and two α-(1→2)-linked mannopyranose residues. In contrast, WbdA(O8) polymerizes trisaccharide repeat units containing single α-(1→3)-, α-(1→2)-, and β-(1→2)-mannopyranoses. These studies illustrate assembly systems exploiting several mannosyltransferases with flexible active sites, arranged in single- and multiple-domain formats.
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Affiliation(s)
- Laura K Greenfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Michele R Richards
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Jianjun Li
- Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada
| | - Warren W Wakarchuk
- Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada
| | - Todd L Lowary
- Alberta Glycomics Centre and Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
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18
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Greenfield LK, Whitfield C. Synthesis of lipopolysaccharide O-antigens by ABC transporter-dependent pathways. Carbohydr Res 2012; 356:12-24. [PMID: 22475157 DOI: 10.1016/j.carres.2012.02.027] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 02/23/2012] [Accepted: 02/24/2012] [Indexed: 01/10/2023]
Abstract
The O-polysaccharide (O-PS; O-antigen) of bacterial lipopolysaccharides is made up of repeating units of one or more sugar residues and displays remarkable structural diversity. Despite the structural variations, there are only three strategies for O-PS assembly. The ATP-binding cassette (ABC)-transporter-dependent mechanism of O-PS biosynthesis is widespread. The Escherichia coli O9a and Klebsiella pneumoniae O2a antigens provide prototypes, which are distinguished by the fine details that link glycan polymerization and chain termination at the cytoplasmic face of the inner membrane to its export via the ABC transporter. Here, we describe the current understanding of these processes. Since glycoconjugate assembly complexes that utilize an ABC transporter-dependent pathway are widespread among the bacterial kingdom, the models described here are expected to extend beyond O-PS biosynthesis systems.
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Affiliation(s)
- Laura K Greenfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada N1G 2W1
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19
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Kubler-Kielb J, Whitfield C, Katzenellenbogen E, Vinogradov E. Identification of the methyl phosphate substituent at the non-reducing terminal mannose residue of the O-specific polysaccharides of Klebsiella pneumoniae O3, Hafnia alvei PCM 1223 and Escherichia coli O9/O9a LPS. Carbohydr Res 2012; 347:186-8. [PMID: 22169179 PMCID: PMC3254779 DOI: 10.1016/j.carres.2011.11.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 11/15/2011] [Accepted: 11/16/2011] [Indexed: 01/21/2023]
Abstract
O-specific polysaccharides of Gram-negative bacteria are synthesized by two different mechanisms: polymerization of the pre-formed O-repeating unit or sequential addition of the monosaccharides to the growing polysaccharide chain. In the second case, growth of the polymer can be further subdivided into two groups depending on the presence or absence of a special monosaccharide or non-sugar substituent that terminates the glycan. A family of polymannose O-polysaccharides provides prototypes for the chain terminating process. Polysaccharides of Klebsiella pneumoniae O3, Hafnia alvei PCM 1223, and Escherichia coli O9 have the same penta-mannose repeating unit. E. coli O9a has tetra-mannose repeat and this structure can be produced by mutants of E. coli O9. The mechanism of biosynthesis of H. alvei 1223 O-polysaccharide has not been reported. Here we show that all above polysaccharides contain the same modification at the non-reducing end; presence of a methyl phosphate group at O-3 of α-mannopyranose, that serves as the signal for termination of the chain elongation.
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Affiliation(s)
- Joanna Kubler-Kielb
- National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Chris Whitfield
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Ewa Katzenellenbogen
- Institure of Immunology and Experimental Therapy, Polish Academy of Science, Wroclaw, Poland
| | - Evgeny Vinogradov
- Institute for Biological Sciences, National Research Council, 100 Sussex Dr., Ottawa ON, K1A 0R6, Canada
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20
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Wang Q, Perepelov AV, Wen L, Shashkov AS, Wang X, Guo X, Knirel YA, Wang L. Identification of the two glycosyltransferase genes responsible for the difference between Escherichia coli O107 and O117 O-antigens. Glycobiology 2011; 22:281-7. [PMID: 21968437 DOI: 10.1093/glycob/cwr137] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The O-antigen is one of the most variable Gram-negative cell constituents, and its specificity is important for bacterial niche adaptation. The observed diversity of O-antigen forms is mainly due to genetic variations in O-antigen gene clusters. Less common is a change of gene function due to nucleotide substitution; a new instance of which is reported here. The O-antigens of E. coli O107 and O117 have similar structures differing only in a single sugar residue (GlcNAc in O107 substituted for Glc in O117). These O-antigen gene clusters contain the same set of 11 genes and share 98.6% overall DNA identity. The function of the genes in the gene clusters have been proposed previously, and a glycosyltransferase gene (wclY) with nucleotide polymorphism in each strain was proposed to transfer different sugars in different strains. To identify the gene responsible for the transfer of different sugars, wclY mutants of E. coli O107 and O117 were constructed, and each mutant was complemented with the wclY genes cloned from both O107 and O117. Structural analysis of the O-antigens of the four recombinant strains identified wclY as a Glc-transferase in O117 and a GlcNAc-transferase in O107. The evolutionary relationship of E. coli O107 and O117 O-antigens is also discussed.
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Affiliation(s)
- Quan Wang
- TEDA School of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjin, People's Republic of China
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21
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Development of an O-antigen serotyping scheme for Cronobacter sakazakii. Appl Environ Microbiol 2011; 77:2209-14. [PMID: 21296934 DOI: 10.1128/aem.02229-10] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cronobacter sakazakii is an opportunistic pathogen that can cause severe infections. Serotyping provides a basis for the categorization of bacterial strains and is an important tool for epidemiological and surveillance purposes. In this study, of the 135 Cronobacter strains tested initially, 119 were identified as C. sakazakii and used. A serotyping scheme for C. sakazakii that classifies strains based on their different O antigens was developed. Seven antisera that exhibited high agglutinin titers (>640) were produced. O2 and O6 antisera were specific for their homologous strains, O4 and O7 antisera gave heterologous titers with O1 and O6 antigens, respectively, and O1, O3, and O5 antisera cross-reacted with each other and require preabsorption with the other two antigens. All of these 119 C. sakazakii strains were clearly assigned to these seven serotypes. O1 and O2 are the dominant serotypes, comprising 69.7% of the isolates. We also characterized the O-antigen gene clusters using restriction fragment length polymorphism (RFLP). The grouping of C. sakazakii strains based on their RFLP banding patterns correlated well with the grouping of strains based on our serotyping scheme. The serotype scheme presented here could prove to be a useful tool for serotyping C. sakazakii isolates.
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22
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Abstract
The O antigen, consisting of many repeats of an oligosaccharide unit, is part of the lipopolysaccharide (LPS) in the outer membrane of Gram-negative bacteria. It is on the cell surface and appears to be a major target for both immune system and bacteriophages, and therefore becomes one of the most variable cell constituents. The variability of the O antigen provides the major basis for serotyping schemes of Gram-negative bacteria. The genes responsible for the synthesis of O antigen are usually in a single cluster known as O antigen gene cluster, and their location on the chromosome within a species is generally conserved. Three O antigen biosynthesis pathways including Wzx/Wzy, ABC-transporter and Synthase have been discovered. In this chapter, the traditional and molecular O serotyping schemes are compared, O antigen structures and gene clusters of well-studied species are described, processes for formation and distribution of the variety of O antigens are discussed, and finally, the role of O antigen in bacterial virulence.
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Affiliation(s)
- Lei Wang
- TEDA School of Biological Sciences and Biotechnology, Nankai University, 23 Hongda Street, TEDA, Tianjin, 300457, China.
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23
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Wang Q, Perepelov AV, Feng L, Knirel YA, Li Y, Wang L. Genetic and structural analyses of Escherichia coli O107 and O117 O-antigens. ACTA ACUST UNITED AC 2008; 55:47-54. [PMID: 19040662 DOI: 10.1111/j.1574-695x.2008.00494.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The O-antigen, consisting of many repeats of an oligosaccharide, is an essential component of the lipopolysaccharide on the surface of Gram-negative bacteria. The O-antigen is one of the most variable cell constituents, and different O-antigen forms are almost entirely due to genetic variations in O-antigen gene clusters. In this paper, we present structural and genetic evidence for a close relationship between Escherichia coli O107 and E. coli O117 O antigens. The O-antigen of E. coli O107 has a pentasaccharide repeating unit with the following structure: -->4)-beta-D-GalpNAc-(1-->3)-alpha-L-Rhap-(1-->4)-alpha-D-GlcpNAc-(1-->4)-beta-D-Galp-(1-->3)-alpha-D-GalpNAc-(1-->, which differs from the known repeating unit of E. coli O117 only in the substitution of D-GlcNAc for D-Glc. The O-antigen gene clusters of E. coli O107 and O117 share 98.6% overall DNA identity and contain the same set of genes in the same organization. It is proposed that one cluster was evolved from another via mutations, and the substitution of a few amino acids residues in predicted glycosyltransferases resulted in the functional change of one such protein for transferring different sugars in O107 (D-GlcNAc) and O117 (D-Glc), leading to different O-antigen structures. This is an example of the O-antigen alteration caused by nucleotide mutations, which is less commonly reported for O-antigen variations.
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Affiliation(s)
- Quan Wang
- TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China
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24
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Liu Y, Fratamico P, Debroy C, Bumbaugh AC, Allen JW. DNA sequencing and identification of serogroup-specific genes in the Escherichia coli O118 O antigen gene cluster and demonstration of antigenic diversity but only minor variation in DNA sequence of the O antigen clusters of E. coli O118 and O151. Foodborne Pathog Dis 2008; 5:449-57. [PMID: 18673069 DOI: 10.1089/fpd.2008.0096] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The DNA sequence of the O antigen gene cluster of an Escherichia coli serogroup O118 strain was determined, and 13 open reading frames (ORFs) were identified, encoding genes required for O antigen sugar biosynthesis, transfer, and processing. Polymerase chain reaction (PCR) assays targeting the wzx (O antigen flippase) and wzy (O antigen polymerase) genes in the O antigen gene cluster of E. coli O118 were designed for identification of these serogroups. Specificity testing using strains belonging to E. coli O118 isolated from various sources, representative strains of 167 other E. coli O serogroups, and 20 non-E. coli bacteria revealed that the PCR assays were specific for E. coli O118. Thus, the PCR assays can be used for rapid identification of E. coli O118 as an alterative to typing using antisera. However, the PCR assays targeting the E. coli O118 wzx and wzy genes were also positive using E. coli serogroup O151 DNA. Therefore, the sequence of the O antigen gene cluster of E. coli O151 was determined, and it was very similar to that of E. coli O118, with only three nucleotide differences. Although the lipopolysaccharide profiles of O118 and O151 showed differences, multilocus sequence typing of E. coli O118 and O151 strains only revealed minor variation at the nucleotide level. Since E. coli O118 strains are more frequently isolated from humans, animals, and the environment than E. coli O151, serogroup O151 may likely be a minor variant of E. coli O118. Further studies are needed to elucidate this possibility.
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Affiliation(s)
- Yanhong Liu
- U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, Pennsylvania 19038, USA.
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25
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Clarke BR, Cuthbertson L, Whitfield C. Nonreducing Terminal Modifications Determine the Chain Length of Polymannose O Antigens of Escherichia coli and Couple Chain Termination to Polymer Export via an ATP-binding Cassette Transporter. J Biol Chem 2004; 279:35709-18. [PMID: 15184370 DOI: 10.1074/jbc.m404738200] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The chain length of bacterial lipopolysaccharide O antigens is regulated to give a modal distribution that is critical for pathogenesis. This paper describes the process of chain length determination in the ATP-binding cassette (ABC) transporter-dependent pathway, a pathway that is widespread among Gram-negative bacteria. Escherichia coli O8 and O9/O9a polymannans are synthesized in the cytoplasm, and an ABC transporter exports the nascent polymer across the inner membrane prior to completion of the LPS molecule. The polymannan O antigens have nonreducing terminal methyl groups. The 3-O-methyl group in serotype O8 is transferred from S-adenosylmethionine by the WbdD(O8) enzyme, and this modification terminates polymerization. Methyl groups are added to the O9a polymannan in a reaction dependent on preceding phosphorylation. The bifunctional WbdD(O9a) catalyzes both reactions, but only the kinase activity controls chain length. Chain termination occurs in a mutant lacking the ABC transporter, indicating that it precedes export. An E. coli wbdD(O9a) mutant accumulated O9a polymannan in the cytoplasm, indicating that WbdD activity coordinates polymannan chain termination with export across the inner membrane.
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Affiliation(s)
- Bradley R Clarke
- Department of Microbiology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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26
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Samuel G, Reeves P. Biosynthesis of O-antigens: genes and pathways involved in nucleotide sugar precursor synthesis and O-antigen assembly. Carbohydr Res 2004; 338:2503-19. [PMID: 14670712 DOI: 10.1016/j.carres.2003.07.009] [Citation(s) in RCA: 387] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The O-antigen is an important component of the outer membrane of Gram-negative bacteria. It is a repeat unit polysaccharide and consists of a number of repeats of an oligosaccharide, the O-unit, which generally has between two and six sugar residues. O-Antigens are extremely variable, the variation lying in the nature, order and linkage of the different sugars within the polysaccharide. The genes involved in O-antigen biosynthesis are generally found on the chromosome as an O-antigen gene cluster, and the structural variation of O-antigens is mirrored by genetic variation seen in these clusters. The genes within the cluster fall into three major groups. The first group is involved in nucleotide sugar biosynthesis. These genes are often found together in the cluster and have a high level of identity. The genes coding for a significant number of nucleotide sugar biosynthesis pathways have been identified and these pathways seem to be conserved in different O-antigen clusters and across a wide range of species. The second group, the glycosyl transferases, is involved in sugar transfer. They are often dispersed throughout the cluster and have low levels of similarity. The third group is the O-antigen processing genes. This review is a summary of the current knowledge on these three groups of genes that comprise the O-antigen gene clusters, focusing on the most extensively studied E. coli and S. enterica gene clusters.
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Affiliation(s)
- Gabrielle Samuel
- School of Molecular and Microbial Biosciences, University of Sydney, Sydney, NSW 2006, Australia
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27
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Mataga N, Chosrowjan H, Taniguchi S, Tanaka F, Kido N, Kitamura M. Femtosecond Fluorescence Dynamics of Flavoproteins: Comparative Studies on Flavodoxin, Its Site-Directed Mutants, and Riboflavin Binding Protein Regarding Ultrafast Electron Transfer in Protein Nanospaces. J Phys Chem B 2002. [DOI: 10.1021/jp020574l] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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28
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Vinogradov E, Frirdich E, MacLean LL, Perry MB, Petersen BO, Duus JØ, Whitfield C. Structures of lipopolysaccharides from Klebsiella pneumoniae. Eluicidation of the structure of the linkage region between core and polysaccharide O chain and identification of the residues at the non-reducing termini of the O chains. J Biol Chem 2002; 277:25070-81. [PMID: 11986326 DOI: 10.1074/jbc.m202683200] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Deamination of LPSs from Klebsiella pneumoniae released O-chain polysaccharides together with a fragment of the core oligosaccharide. The structures of the products from serotypes O1, O2a, O2a,c, O3, O4, O5, and O12 were determined by NMR spectroscopy and chemical methods, identifying the linkage region between the O antigens and the core as well as novel residues at the non-reducing ends of the polysaccharides. All serotypes had an identical linkage between the O chain and core.
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Affiliation(s)
- Evgeny Vinogradov
- Institute for Biological Sciences, National Research Council, Ottawa, Ontario K1A 0R6, Canada.
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29
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Chen L, Zhu Y, Kong F. Synthesis of alpha-Manp-(1-->2)-alpha-Manp-(1-->3)-alpha-Manp-(1-->3)-Manp, the tetrasaccharide repeating unit of Escherichia coli O9a, and alpha-Manp-(1-->2)-alpha-Manp-(1-->2)-alpha-Manp-(1-->3)-alpha-Manp-(1-->3)-Manp, the pentasaccharide repeating unit of E. coli O9 and Klebsiella O3. Carbohydr Res 2002; 337:383-90. [PMID: 11861011 DOI: 10.1016/s0008-6215(02)00011-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The tetrasaccharide repeating unit of Escherichia coli O9a, alpha-D-Manp-(1-->2)-alpha-D-Manp-(1-->3)-alpha-D-Manp-(1-->3)-D-Manp, and the pentasaccharide repeating unit of E. coli O9 and Klebsiella O3, alpha-D-Manp-(1-->2)-alpha-D-Manp-(1-->2)-alpha-D-Manp-(1-->3)-alpha-D-Manp-(1-->3)-D-Manp, were synthesized as their methyl glycosides. Thus, selective 3-O-allylation of p-methoxyphenyl alpha-D-mannopyranoside via a dibutyltin intermediate gave p-methoxyphenyl 3-O-allyl-alpha-D-mannopyranoside (2) in good yield. Benzoylation (-->3), then removal of 1-O-methoxyphenyl (right arrow4), and subsequent trichloroacetimidation afforded the 3-O-allyl-2,4,6-tri-O-benzoyl-alpha-D-mannopyranosyl trichloroacetimidate (5). Condensation of 5 with methyl 4,6-O-benzylidene-alpha-D-mannopyranoside (6) selectively afforded the (1-->3)-linked disaccharide 7. Benzoylation of 7, debenzylidenation, benzoylation, and deallylation gave methyl 2,4,6-tri-O-benzoyl-alpha-D-mannopyranosyl-(1-->3)-2,4,6-tri-O-benzoyl-alpha-D-mannopyranoside (11) as the disaccharide acceptor. Coupling of 11 with (1-->2)-linked mannose disaccharide donor 17 or trisaccharide donor 21, followed by deacylation, furnished the target tetrasaccharide and pentasaccharide, respectively.
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Affiliation(s)
- Langqiu Chen
- Research Center for Eco-Environmental Sciences, Academia Sinica, PO Box 2871, 100085, Beijing, PR China
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30
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Abstract
Bacterial lipopolysaccharides (LPS) typically consist of a hydrophobic domain known as lipid A (or endotoxin), a nonrepeating "core" oligosaccharide, and a distal polysaccharide (or O-antigen). Recent genomic data have facilitated study of LPS assembly in diverse Gram-negative bacteria, many of which are human or plant pathogens, and have established the importance of lateral gene transfer in generating structural diversity of O-antigens. Many enzymes of lipid A biosynthesis like LpxC have been validated as targets for development of new antibiotics. Key genes for lipid A biosynthesis have unexpectedly also been found in higher plants, indicating that eukaryotic lipid A-like molecules may exist. Most significant has been the identification of the plasma membrane protein TLR4 as the lipid A signaling receptor of animal cells. TLR4 belongs to a family of innate immunity receptors that possess a large extracellular domain of leucine-rich repeats, a single trans-membrane segment, and a smaller cytoplasmic signaling region that engages the adaptor protein MyD88. The expanding knowledge of TLR4 specificity and its downstream signaling pathways should provide new opportunities for blocking inflammation associated with infection.
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Affiliation(s)
- Christian R H Raetz
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA.
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31
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Abstract
In pathogenic bacteria, point and other simple mutations can provide a strong selective advantage during the course of a single infection. Our understanding of the importance of these randomly occurring mutations has been hampered by a lack of technologies allowing mutation scanning on a genomic scale. Here, a novel technology is described that makes it possible to scan, in a single Southern blot experiment, the sequence identity of genomic regions with a combined length of hundreds of kilobases.
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Affiliation(s)
- E V Sokurenko
- Dept of Microbiology, University of Washington, Seattle 98195, USA.
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