Linked Life Data

17144668

Source:http://linkedlifedata.com/resource/pubmed/id/17144668

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
49
pubmed:dateCreated
2006-12-5
pubmed:abstractText
The vitamin K-dependent carboxylase is an integral membrane protein which is required for the post-translational modification of a variety of vitamin K-dependent proteins. Previous studies have suggested carboxylase is a glycoprotein with N-linked glycosylation sites. In this study, we identify the N-glycosylation sites of carboxylase by mass spectrometric peptide mapping analyses combined with site-directed mutagenesis. Our mass spectrometric results show that the N-linked glycosylation in carboxylase occurs at positions N459, N550, N605, and N627. Eliminating these glycosylation sites by changing asparagine to glutamine caused the mutant carboxylase to migrate faster on SDS-PAGE gels, adding further evidence that these sites are glycosylated. In addition, the mutation studies identified N525, a site that cannot be recovered by mass spectroscopy analysis, as a glycosylation site. Furthermore, the potential glycosylation site at N570 is glycosylated only if all five natural glycosylation sites are simultaneously mutated. Removal of the oligosaccharides by glycosidase from wild-type carboxylase or by elimination of the functional glycosylation sites by site-directed mutagenesis did not affect either the carboxylation or epoxidation activity when the small FLEEL pentapeptide was used as a substrate, suggesting that N-linked glycosylation is not required for the enzymatic function of carboxylase. In contrast, when site N570 and the five natural glycosylation sites were mutated simultaneously, the resulting carboxylase protein was degraded. Our results suggest that N-linked glycosylation is not essential for carboxylase enzymatic activity but is important for protein folding and stability.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
12
pubmed:volume
45
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
14755-63
pubmed:dateRevised
2007-12-3
pubmed:meshHeading
pubmed-meshheading:17144668-Amino Acid Sequence, pubmed-meshheading:17144668-Animals, pubmed-meshheading:17144668-Binding Sites, pubmed-meshheading:17144668-Carbon-Carbon Ligases, pubmed-meshheading:17144668-Escherichia coli, pubmed-meshheading:17144668-Glycosylation, pubmed-meshheading:17144668-Humans, pubmed-meshheading:17144668-Insects, pubmed-meshheading:17144668-Kinetics, pubmed-meshheading:17144668-Models, Molecular, pubmed-meshheading:17144668-Molecular Sequence Data, pubmed-meshheading:17144668-Mutagenesis, pubmed-meshheading:17144668-Oligopeptides, pubmed-meshheading:17144668-Oligosaccharides, pubmed-meshheading:17144668-Peptide Fragments, pubmed-meshheading:17144668-Protein Conformation, pubmed-meshheading:17144668-Recombinant Proteins, pubmed-meshheading:17144668-Spectrometry, Mass, Matrix-Assisted Laser...
pubmed:year
2006
pubmed:articleTitle
Identification of the N-linked glycosylation sites of vitamin K-dependent carboxylase and effect of glycosylation on carboxylase function.
pubmed:affiliation
Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
pubmed:publicationType
Journal Article, Research Support, N.I.H., Extramural