Taxonomic group: bacteria / Proteobacteria
(Phylum: Proteobacteria)
Associated disease: infection due to Escherichia coli [ICD11:
XN6P4 
]
NCBI PubMed ID: 8694758Journal NLM ID: 2984726RPublisher: London, UK : Published by Portland Press on behalf of the Biochemical Society
Institutions: Departamento de Bioquimica y Biologia Molecular, Universidad de Leon, Spain
Colominic acid is a capsular homopolymer from Escherichia coli K1 composed of α(2-8)-linked N-acetyl-D-neuraminic acid (NeuAc) residues. Recently, we have described that NeuAc synthesis in this bacterium occurs through the action of NeuAc lyase (EC 4.1.3.3) [ Rodriguez-Aparicio, Ferrero and Reglero (1995) Biochem. J.308, 501-505]. In the present work we analysed and characterized this enzyme. E. coli K1 NeuAc lyase is detected from the early logarithmic phase of growth, is induced by NeuAc and is not repressed by glucose. The enzyme was purified to apparent homogeneity (312-fold) using two types of hydrophobic chromatographies (butyl-agarose and phenyl-Sepharose CL-4B), gel filtration on Sephacryl S-200, and anion-exchange chromatography on DEAE-FPLC. The pure enzyme, whose amino acid composition and N-terminal amino acid sequence are also established, has a native molecular mass, estimated by gel filtration, of 135 +/- 3 kDa, whereas its molecular mass in SDS/PAGE was 33 +/- 1 kDa. The enzyme was able to synthesize and cleave NeuAc in a reversible reaction. The maximal rate of catalysis was achieved in 125 mM Tris/HCl buffer, pH 7.8, at 37 degrees C. Under these conditions, the K(m) values calculated for N-acetyl-D-mannosamine and pyruvate (condensation direction), and NeuAc (hydrolysis direction) were 7.7, 8.3 and 4.8 mM respectively. NeuAc synthesis by the pure enzyme was activated by Ca2+ and inhibited by Mn2+ and NeuAc, whereas the enzyme cleavage direction was inhibited by Ca2+, Mn2+ and pyruvate. The reaction products, NeuAc and pyruvate, and Ca2+ are able to regulate the direction of this enzyme (synthesis or cleavage of sialic acid) and, accordingly, to modulate colominic acid biosynthesis.
biosynthesis, capsular, polysaccharide, Escherichia, Escherichia coli, acid, sialic acid, colominic acid, Escherichia coli K1, lyase
Structure type: homopolymer
Location inside paper: abstract, p.157
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
Biosynthesis and genetic data: biosynthetic data
Related record ID(s): 6832, 7487, 8356
NCBI Taxonomy refs (TaxIDs): 1392869Reference(s) to other database(s): GTC:G30588ZL, GlycomeDB:
677
Show glycosyltransferases
There is only one chemically distinct structure:
Found 
report error