Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
NCBI PubMed ID: 10574996Journal NLM ID: 2985121RPublisher: Baltimore, MD: American Society for Biochemistry and Molecular Biology
Correspondence: wong
scripps.edu
Institutions: Department of Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037
The capsular polysaccharide of Escherichia coli K92 contains alternating -8-NeuAcα2- and -9-NeuAcα2- linkages. The enzyme catalyzing this polymerizing reaction has been cloned from the genomic DNA of E. coli K92. The 1.2-kilobase polymerase chain reaction fragment was subcloned in pRSET vector and the protein was expressed in the BL21(DE3) strain of E. coli with a hexameric histidine at its N-terminal end. The enzyme was isolated in the supernatant after lysis of the cells and fractionated by ultracentrifugation. Western blotting using anti-histidine antibody showed the presence of a band that migrated at about 47.5 kDa on both reducing and nonreducing SDS-polyacrylamide gel electrophoresis, indicating a monomeric enzyme. Among the carbohydrate acceptors tested, N-acetylneuraminic acid and the gangliosides G(D3) and G(Q1b) were preferred substrates. The cell-free enzyme reaction products obtained were characterized by NMR and mass spectrometry, which indicated the presence of both α2,9- and α2,8-linked polysialyl structure. The K92 neuS gene was used to transform the K1 strain of E. coli, the capsule of which contains only -8-NeuAcα2- linkages. Analysis of the polysaccharides isolated from these transformed cells is consistent with the presence of both -8-NeuAcα2- and -9-NeuAcα2- linkages. Our results suggest that the neuS gene product of E. coli K92 catalyzes the synthesis of polysialic acid with α2,9- and α2,8-linkages in vitro and in vivo.
biosynthesis, expression, Escherichia, Escherichia coli, transferase, CPS, polysialic acid
Structure type: polymer chemical repeating unit
Location inside paper: abstract
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
Methods: NMR-2D, NMR, MS
Biosynthesis and genetic data: genetic data
Related record ID(s): 3427, 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:
Found 
report error