Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
The structure was elucidated in this paperNCBI PubMed ID: 17384120Publication DOI: 10.1093/glycob/cwm032Journal NLM ID: 9104124Publisher: IRL Press at Oxford University Press
Correspondence: wvann
helix.nih.gov
Institutions: Laboratory of Bacterial Polysaccharides, Center for Biologics Evaluation and Research, FDA, Bethesda, MD, USA
Escherichia coli K92 produces a capsular polysialic acid with alternating α2,8 α2,9 NeuNAc linkages. This polysaccharide is cross reactive with the neuroinvasive pathogen Neisseria meningitidis Group C. The K92 polysialyltransferase catalyzes the synthesis of the polysialic acid with alternating linkages by the transfer of NeuNAc from CMP-NeuNAc to the non-reducing end of the growing polymer. We used a fluorescent based HPLC assay to characterize the process of chain extension. The polysialyltransferase elongates the acceptor GT3-FCHASE in a biphasic fashion. The initial phase polymers are characterized by accumulation of product containing 1 to 8 additional sialic acid residues. This phase is followed by a very rapid formation of high molecular weight polymer as the accumulated oligosaccharides containing 8-10 sialic acids are consumed. The high molecular weight polymer contains 90-100 sialic acids and is sensitive to degradation by periodate and K1-5 endoneuraminidase suggesting that the polymer contains the alternating structure. The polymerization reaction does not appear to be strictly processive, since oligosaccharides of each intermediate size were detected before accumulation of high molecular weight polymer. Synthesis can be blocked by CMP-9-azido-NeuNAc. These results suggest that the K92 polysialyltransferase forms both α2,8 and α2,9 linkages in a successive and non-processive fashion
capsular polysaccharides, sialic acid, polysialyltransferase, chain extension, processivity
Structure type: oligomer
Location inside paper: p.738
Aglycon: polysialic acid (n=10-12)
Trivial name: 9-azido-derivative of polysialic acid
Contained glycoepitopes: IEDB_136794,IEDB_146100,IEDB_149174,SB_170,SB_171,SB_172,SB_84
Methods: biochemical methods, HPLC
Enzymes that release or process the structure: K92 polysialyltransferase
Biosynthesis and genetic data: biochemical data
Synthetic data: enzymatic
Comments, role: polysialyltransferase forms both a2,8 and a2,9 linkages in polymer
Related record ID(s): 21425, 21696
NCBI Taxonomy refs (TaxIDs): 562
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There is only one chemically distinct structure:
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