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Publication Abstract from PubMed

Protein glycosylation catalyzed by the O-GlcNAc transferase (OGT) plays a critical role in various biological processes. In Streptococcus pneumoniae, the core enzyme GtfA and co-activator GtfB form an OGT complex to glycosylate the serine-rich repeat (SRR) of adhesin PsrP (pneumococcal serine-rich repeat protein), which is involved in the infection and pathogenesis. Here we report the 2.0 A crystal structure of GtfA, revealing a beta-meander add-on domain beyond the catalytic domain. It represents a novel add-on domain, which is distinct from the all-alpha-tetratricopeptide repeats in the only two structure-known OGTs. Structural analyses combined with binding assays indicate that this add-on domain contributes to forming an active GtfA-GtfB complex and recognizing the acceptor protein. In addition, the in vitro glycosylation system enables us to map the O-linkages to the serine residues within the first SRR of PsrP. These findings suggest that fusion with an add-on domain might be a universal mechanism for diverse OGTs that recognize varying acceptor proteins/peptides.

Structure of a Novel O-Linked N-Acetyl-d-glucosamine (O-GlcNAc) Transferase, GtfA, Reveals Insights into the Glycosylation of Pneumococcal Serine-rich Repeat Adhesins.,Shi WW, Jiang YL, Zhu F, Yang YH, Shao QY, Yang HB, Ren YM, Wu H, Chen Y, Zhou CZ J Biol Chem. 2014 Jul 25;289(30):20898-20907. Epub 2014 Jun 16. PMID:24936067^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.