Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
NCBI PubMed ID: 372481Journal NLM ID: 2985109RPublisher: Rockefeller University Press
The chemical basis for the alternating antigenic change called form variation noted for the Escherichia coli K1-capsular polysaccharide has been shown by 13C nuclear magnetic resonance to be a result of random O-acetylation of C7 and C9 carbons of the α-2-8-linked sialic acid homopolymer. A serologic method (antiserum agar) was developed to identify and isolate the form variants. The O-acetyl positive and O-acetyl negative K1 polysaccharides had unique biochemical and immunologic properties. The O-acetyl-positive variants resisted neuraminidase hydrolysis in contrast to the susceptibility of the O-acetyl negative variant to this enzyme. In addition, O-acetylation altered the antigenicity of the O-acetyl polysaccharides. When injected as whole organisms, O-acetyl positive organisms produced anti-K1 -antibodies in rabbits specific for this polysaccharide variant. O-acetyl negative organisms were comparatively less immunogenic; however, antibodies induced by these organisms reacted with both K1 polysaccharide variants. Burros, injected with either variant, produced antibodies reactive with both K1 polysaccharides.
Structure type: homopolymer
Trivial name: colominic acid
Compound class: K-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: 13C NMR
NCBI Taxonomy refs (TaxIDs): 1392869Reference(s) to other database(s): GTC:G96197DM, GlycomeDB:
11429
Show glycosyltransferases
There is only one chemically distinct structure: