Linked Life Data

15509570

Source:http://linkedlifedata.com/resource/pubmed/id/15509570

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2005-2-7
pubmed:abstractText
The major cell-surface carbohydrates (lipooligosaccharide, capsule, and glycoprotein N-linked heptasaccharide) of Campylobacter jejuni NCTC 11168 contain Gal and/or GalNAc residues. GalE is the sole annotated UDP-glucose 4-epimerase in this bacterium. The presence of GalNAc residues in these carbohydrates suggested that GalE might be a UDP-GlcNAc 4-epimerase. GalE was shown to epimerize UDP-Glc and UDP-GlcNAc in coupled assays with C. jejuni glycosyltransferases and in sugar nucleotide epimerization equilibria studies. Thus, GalE possesses UDP-GlcNAc 4-epimerase activity and was renamed Gne. The Km(app) values of a purified MalE-Gne fusion protein for UDP-GlcNAc and UDP-GalNAc are 1087 and 1070 microm, whereas those for UDP-Glc and UDP-Gal are 780 and 784 microm. The kcat and kcat/Km(app) values were three to four times higher for UDP-GalNAc and UDP-Gal than for UDP-GlcNAc and UDP-Glc. The comparison of the kinetic parameters of MalE-Gne to those of other characterized bacterial UDP-GlcNAc 4-epimerases indicated that Gne is a bifunctional UDP-GlcNAc/Glc 4-epimerase. The UDP sugar-binding site of Gne was modeled by using the structure of the UDP-GlcNAc 4-epimerase WbpP from Pseudomonas aeruginosa. Small differences were noted, and these may explain the bifunctional character of the C. jejuni Gne. In a gne mutant of C. jejuni, the lipooligosaccharide was shown by capillary electrophoresis-mass spectrometry to be truncated by at least five sugars. Furthermore, both the glycoprotein N-linked heptasaccharide and capsule were no longer detectable by high resolution magic angle spinning NMR. These data indicate that Gne is the enzyme providing Gal and GalNAc residues with the synthesis of all three cell-surface carbohydrates in C. jejuni NCTC 11168.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
11
pubmed:volume
280
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4792-802
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:15509570-Amino Acid Motifs, pubmed-meshheading:15509570-Amino Acid Sequence, pubmed-meshheading:15509570-Binding Sites, pubmed-meshheading:15509570-Campylobacter jejuni, pubmed-meshheading:15509570-Carbohydrate Epimerases, pubmed-meshheading:15509570-Carbohydrate Sequence, pubmed-meshheading:15509570-Carbohydrates, pubmed-meshheading:15509570-Cell Membrane, pubmed-meshheading:15509570-Electrophoresis, Capillary, pubmed-meshheading:15509570-Glycoproteins, pubmed-meshheading:15509570-Ions, pubmed-meshheading:15509570-Kinetics, pubmed-meshheading:15509570-Magnetic Resonance Spectroscopy, pubmed-meshheading:15509570-Mass Spectrometry, pubmed-meshheading:15509570-Models, Biological, pubmed-meshheading:15509570-Models, Chemical, pubmed-meshheading:15509570-Models, Molecular, pubmed-meshheading:15509570-Molecular Sequence Data, pubmed-meshheading:15509570-Mutation, pubmed-meshheading:15509570-Oligonucleotides, pubmed-meshheading:15509570-Plasmids, pubmed-meshheading:15509570-Polysaccharides, pubmed-meshheading:15509570-Protein Conformation, pubmed-meshheading:15509570-Protons, pubmed-meshheading:15509570-Pseudomonas aeruginosa, pubmed-meshheading:15509570-Recombinant Fusion Proteins, pubmed-meshheading:15509570-Uridine Diphosphate
pubmed:year
2005
pubmed:articleTitle
A single bifunctional UDP-GlcNAc/Glc 4-epimerase supports the synthesis of three cell surface glycoconjugates in Campylobacter jejuni.
pubmed:affiliation
Institute for Biological Sciences, National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't