Identification of the N-linked glycosylation sites of vitamin K-dependent carboxylase and effect of glycosylation on carboxylase function.

ABSTRACT: 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

SUBMITTER: Tie JK 

PROVIDER: S-EPMC3956053 | biostudies-literature | 2006 Dec

REPOSITORIES: biostudies-literature