title: The capsule polysaccharide structure and biogenesis for non-O1 Vibrio cholerae NRT36S: genes are embedded in the LPS region.
abstract: BACKGROUND
  In V. cholerae, the biogenesis of capsule polysaccharide is poorly understood. The elucidation of capsule structure and biogenesis is critical to understanding the evolution of surface polysaccharide and the internal relationship between the capsule and LPS in this species. V. cholerae serogroup O31 NRT36S, a human pathogen that produces a heat-stable enterotoxin (NAG-ST), is encapsulated. Here, we report the covalent structure and studies of the biogenesis of the capsule in V. cholerae NRT36S.
  
  
  RESULTS
  The structure of the capsular (CPS) polysaccharide was determined by high resolution NMR spectroscopy and shown to be a complex structure with four residues in the repeating subunit. The gene cluster of capsule biogenesis was identified by transposon mutagenesis combined with whole genome sequencing data (GenBank accession DQ915177). The capsule gene cluster shared the same genetic locus as that of the O-antigen of lipopolysaccharide (LPS) biogenesis gene cluster. Other than V. cholerae O139, this is the first V. cholerae CPS for which a structure has been fully elucidated and the genetic locus responsible for biosynthesis identified.
  
  
  CONCLUSIONS
  The co-location of CPS and LPS biosynthesis genes was unexpected, and would provide a mechanism for simultaneous emergence of new O and K antigens in a single strain. This, in turn, may be a key element for V. cholerae to evolve new strains that can escape immunologic detection by host populations.
authors.affiliation: Department of Epidemiology and Preventive Medicine, University of Maryland, Baltimore, Baltimore, MD 21201, USA. ychen@epi.umaryland.edu <ychen@epi.umaryland.edu>
authors.forename: Yuansha
authors.initials: Y
authors.lastname: Chen
authors.forename: Peter
authors.initials: P
authors.lastname: Bystricky
authors.forename: Jacob
authors.initials: J
authors.lastname: Adeyeye
authors.forename: Pinaki
authors.initials: P
authors.lastname: Panigrahi
authors.forename: Afsar
authors.initials: A
authors.lastname: Ali
authors.forename: Judith A
authors.initials: JA
authors.lastname: Johnson
authors.forename: C A
authors.initials: CA
authors.lastname: Bush
authors.forename: J G
authors.initials: JG
authors.lastname: Morris
authors.forename: O C
authors.initials: OC
authors.lastname: Stine
mesh_terms: D000595:Amino Acid Sequence; D016667:Bacterial Capsules / Q000096:biosynthesis* / Q000737:chemistry; D001483:Base Sequence; D002849:Chromatography, Gas / Q000379:methods; D002850:Chromatography, Gel; D004251:DNA Transposable Elements / Q000235:genetics; D016680:Genome, Bacterial; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism; D015151:Immunoblotting; D008070:Lipopolysaccharides / Q000096:biosynthesis* / Q000737:chemistry; D008854:Microscopy, Electron / Q000379:methods; D008969:Molecular Sequence Data; D016296:Mutagenesis; D019906:Nuclear Magnetic Resonance, Biomolecular; D019081:O Antigens / Q000096:biosynthesis / Q000235:genetics; D044163:Vibrio cholerae non-O1 / Q000235:genetics* / Q000378:metabolism*
chemical_list: D004251:DNA Transposable Elements; D008070:Lipopolysaccharides; D019081:O Antigens; D016695:Glycosyltransferases