The lipid-linked oligosaccharide donor specificities of Trypanosoma brucei oligosaccharyltransferases.

ABSTRACT: We recently presented a model for site-specific protein N-glycosylation in Trypanosoma brucei whereby the TbSTT3A oligosaccharyltransferase (OST) first selectively transfers biantennary Man(5)GlcNAc(2) from the lipid-linked oligosaccharide (LLO) donor Man(5)GlcNAc(2)-PP-Dol to N-glycosylation sequons in acidic to neutral peptide sequences and TbSTT3B selectively transfers triantennary Man(9)GlcNAc(2) to any remaining sequons. In this paper, we investigate the specificities of the two OSTs for their preferred LLO donors by glycotyping the variant surface glycoprotein (VSG) synthesized by bloodstream-form T. brucei TbALG12 null mutants. The TbALG12 gene encodes the α1-6-mannosyltransferase that converts Man(7)GlcNAc(2)-PP-Dol to Man(8)GlcNAc(2)-PP-Dol. The VSG synthesized by the TbALG12 null

SUBMITTER: Izquierdo L 

PROVIDER: S-EPMC3311286 | biostudies-literature | 2012 May

REPOSITORIES: biostudies-literature