Distinct donor and acceptor specificities of Trypanosoma brucei oligosaccharyltransferases.

ABSTRACT: Asparagine-linked glycosylation is catalysed by oligosaccharyltransferase (OTase). In Trypanosoma brucei OTase activity is catalysed by single-subunit enzymes encoded by three paralogous genes of which TbSTT3B and TbSTT3C can complement a yeast Deltastt3 mutant. The two enzymes have overlapping but distinct peptide acceptor specificities, with TbSTT3C displaying an enhanced ability to glycosylate sites flanked by acidic residues. TbSTT3A and TbSTT3B, but not TbSTT3C, are transcribed in the bloodstream and procyclic life cycle stages of T. brucei. Selective knockdown and analysis of parasite protein N-glycosylation showed that TbSTT3A selectively transfers biantennary Man(5)GlcNAc(2) to specific glycosylation sites whereas TbSTT3B selectively transfers triantennary Man(9)GlcNAc(2) to others

SUBMITTER: Izquierdo L 

PROVIDER: S-EPMC2722254 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature