Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
];
infection due to Neisseria meningitidis [ICD11:
XN1DV ]
NCBI PubMed ID: 8830246Journal NLM ID: 8712028Publisher: Blackwell Publishing
Correspondence: mwessels
warren.med.harvard.edu
Institutions: Channig Laboratory, Brigham and Women's Hospital, and Division of Infections Diseases, Beth Israel Hospital, Harvard Medical School, 180, Longwood Avenue, Boston, Massachusetts 02115, Division of Infections Disease, Children's Hospital and Medical Center, University of Washington, Seattle, Washington 98105
Group B Streptococcus (GBS) is the foremost cause of neonatal sepsis and meningitis in the United States. A major virulence factor for GBS is its capsular polysaccharide, a high molecular weight polymer of branched oligosaccharide subunits. N-acetylneuraminic acid (Neu5Ac or sialic acid), at the end of the polysaccharide side chains, is critical to the virulence function of the capsular polysaccharide. Neu5Ac must be activated by CMP-Neu5Ac synthetase before it is incorporated into the polymer. We showed previously that a transposon mutant of a serotype III GBS strain which had no detectable capsular Neu5Ac was deficient in CMP-Neu5Ac-synthetase activity (Wessels et al., 1992). In this paper, we report the identification and characterization of cpsF, a gene interrupted by transposon insertion in the previously described Neu5Ac-deficient mutant. The predicted amino acid sequence of the cpsF gene product shares 57% similarity and 37% identity with CMP-Neu5Ac synthase encoded by the Escherichia coli K1 gene, neuA. The enzymatic function of the protein encoded by cpsF was established by cloning the gene E. coli under the control of the T7 polymerase/promoter. Lysates of E. coli in which the cpsF gene product was expressed, catalysed the condensation of CTP with Neu5Ac to form CMP-Neu5Ac. In addition, when CMP-Neu5Ac synthetase-deficient mutant of E. coli K1 was transformed with cpsF, K1 antigen expression was restored. We concluded that cpsF encodes CMP-Neu5Ac synthetase in type III GBS, and that the GBS enzyme can function in the capsule-synthesis of a heterologous bacterial species.
biosynthesis, Streptococcus, Escherichia coli, capsular polysaccharide, synthetase, polysaccharide biosynthesis
Structure type: homopolymer
Location inside paper: p.555
Trivial name: colominic acid sodium salt, colominic acid, type B polysaccharide, polysialic acid, PSA, oligosaccharide repeating unit, α-2,8-linked polysialic acid
Compound class: CPS, O-polysaccharide, K-antigen, O-antigen
Contained glycoepitopes: IEDB_136794,IEDB_141115,IEDB_142352,IEDB_146100,IEDB_149174,IEDB_150072,IEDB_150937,IEDB_153199,IEDB_226810,IEDB_558870,IEDB_983929,SB_170,SB_171,SB_172,SB_35,SB_42,SB_84
Methods: DNA techniques, genetic methods, biochemical methods, bioinformatic analysis
Biosynthesis and genetic data: biosynthesis data, genetic data
NCBI Taxonomy refs (TaxIDs): 1392869,
487Reference(s) to other database(s): GTC:G30588ZL, GlycomeDB:
677
Show glycosyltransferases
There is only one chemically distinct structure:
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