Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.6.3.1 (Mg2+-ATPase)
 1,484 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The lipopolysaccharide (LPS) O-antigen of Yersinia enterocolitica serotype O:8 is formed by branched pentasaccharide repeat units that contain N-acetylgalactosamine (GalNAc), L-fucose (Fuc), D-galactose (Gal), D-mannose (Man), and 6-deoxy-D-gulose (6d-Gul). Its biosynthesis requires at least enzymes for the synthesis of each nucleoside diphosphate-activated sugar precursor; five glycosyltransferases, one for each sugar residue; a flippase (Wzx); and an O-antigen polymerase (Wzy). As this LPS shows a characteristic preferred O-antigen chain length, the presence of a chain length determinant protein (Wzz) is also expected. By targeted mutagenesis, we identify within the O-antigen gene cluster the genes encoding Wzy and Wzz. We also present genetic and biochemical evidence showing that the gene previously called galE encodes a UDP-N-acetylglucosamine-4-epimerase (EC 5.1.3.7) required for the biosynthesis of the first sugar of the O-unit. Accordingly, the gene was renamed gne. Gne also has some UDP-glucose-4-epimerase (EC 5.1.3.2) activity, as it restores the core production of an Escherichia coli K-12 galE mutant. The three-dimensional structure of Gne was modeled based on the crystal structure of E. coli GalE. Detailed structural comparison of the active sites of Gne and GalE revealed that additional space is required to accommodate the N-acetyl group in Gne and that this space is occupied by two Tyr residues in GalE whereas the corresponding residues present in Gne are Leu136 and Cys297. The Gne Leu136Tyr and Cys297Tyr variants completely lost the UDP-N-acetylglucosamine-4-epimerase activity while retaining the ability to complement the LPS phenotype of the E. coli galE mutant. Finally, we report that Yersinia Wzx has relaxed specificity for the translocated oligosaccharide, contrary to Wzy, which is strictly specific for the O-unit to be polymerized.
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PMID:Functional characterization of Gne (UDP-N-acetylglucosamine-4-epimerase), Wzz (chain length determinant), and Wzy (O-antigen polymerase) of Yersinia enterocolitica serotype O:8. 1210 46

Escherichia coli O11 belongs to Shiga toxin-producing Escherichia coli (STEC), which can cause food-borne disease, hemorrhagic colitis, and hemolytic-uremic syndrome (HUS) in humans. Because of its character of specificity, the O-antigen gene cluster provides the best material for the selection of molecular markers which can be used for rapid genotyping of bacterial strain. In this study, the E.coli O11 O-antigen gene cluster was amplified by Long-range PCR and was sequenced using Shotgun-sequencing approach. Twelve open reading frames were assigned functions on the basis of homology in the E. coli O11 O-antigen gene cluster, including UDP-N-acetyl glucosamine-4-epimerase gene (gne), genes responsible for the biosynthesis of GDP-L-fucose (gmd, fcl, gmm, manC, manB), glycosyl transferase genes, O-unit flippase gene (wzx) and O-antigen polymerase gene (wzy). By polymerase chain reaction against representative stains for all the 166 E. coli and 43 Shigella O serotypes, two genes and four pairs of primers were identified to be specific to E. coli O11. Further PCR was done to detect E. coli O11 from the environmental specimens, and the sensitivities for detecting E.coli O11 from the pork and dejecta specimens were 0.25 cfu/g and 2.5 x 10(3) cfu/g, respectively. Moreover, eight probes were designed and proved to be unique to E. coli O11, which provides the basis for a sensitive test of the rapid detection of E. coli O11 by DNA microarray method.
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PMID:[Sequence of Escherichia coli O11 O-antigen gene cluster and identification of molecular markers specific to O11]. 1693 98