Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
NCBI PubMed ID: 11479272Publication DOI: 10.1093/glycob/11.8.613Journal NLM ID: 9104124Publisher: IRL Press at Oxford University Press
Institutions: Laboratory of Bacterial Toxins, Division of Bacterial, Parasitic and Allergenic Products, Center for Biologics Evaluation and Research, 8800 Rockville Pike, Bethesda, MD, USA
We have chosen E. coli K92, which produces the alternating structure α(2-8)neuNAc α(2-9)neuNAc as a model system for studying bacterial polysaccharide biosynthesis. We have shown that the polysialyltransferase encoded by the K92 neuS gene can synthesize both α(2-8) and α(2-9) neuNAc linkages in vivo by 13C-nuclear magnetic resonance analysis of polysaccharide isolated from a heterologous strain containing the K92 neuS gene. The K92 polysialyltransferase is associated with the membrane in lysates of cells harboring the neuS gene in expression vectors. Although the enzyme can transfer sialic acid to the nonreducing end of oligosaccharides with either linkage, it is unable to initiate chain synthesis without exogenously added polysialic acid. Thus, the polysialyltransferase encoded by neuS is not sufficient for de novo synthesis of polysaccharide but requires another membrane component for initiation. The acceptor specificity of this polysialyltransferase was studied using sialic acid oligosaccharides of various structures as exogenous acceptors. The enzyme can transfer to the nonreducing end of all bacteria polysialic acids, but has a definite preference for α(2-8) acceptors. Gangliosides containing neuNAc α(2-8)neuNAc are elongated, whereas monsialylated gangliosides are not. Disialylgangliosides are better acceptors than short oligosaccharides, suggesting a lipid-linked oligosaccharide may be preferred in the elongation reaction. These studies show that the K92 polysialyltransferase catalyzes an elongation reaction that involves transfer of sialic acid from CMP-sialic acid to the nonreducing end of two different acceptor substrates
polysialic acid, E. coli, polysialyltransferase
Structure type: polymer chemical repeating unit
Trivial name: colominic acid, polysialic acid, α-2,8/2,9-linked polysialic acid
Compound class: CPS, K-antigen
Contained glycoepitopes: IEDB_136794,IEDB_146100,IEDB_149174,IEDB_150937,IEDB_153199,SB_170,SB_171,SB_172,SB_35,SB_42,SB_84
Enzymes that release or process the structure: polysialyltransferase
Biosynthesis and genetic data: biochemical data
Related record ID(s): 8310, 101038, 106935, 126508
NCBI Taxonomy refs (TaxIDs): 562Reference(s) to other database(s): GTC:G85948DP, GlycomeDB:
26537
Show glycosyltransferases
There is only one chemically distinct structure:
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