4PQG: Crystal Structure Of The Pneumococcal O-glcnac Transferase Gtfa In Complex With Udp And Glcnac

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.
PDB ID: 4PQGDownload
MMDB ID: 120858
PDB Deposition Date: 2014/3/3
Updated in MMDB: 2014/08
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
Similar Structures:
Biological Unit for 4PQG: monomeric; determined by author
Molecular Components in 4PQG
Label Count Molecule
Protein (1 molecule)
Glycosyltransferase Gtf1
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB