3rce
Bacterial oligosaccharyltransferase PglB
Structural highlights
FunctionPGLB_CAMLR Oligosaccharyltransferase that catalyzes the transfer of a preassembled heptasaccharide from a lipid donor to an asparagine residue in nascent polypeptide chains, affording a beta-linked glycan to the asparagine side chain of target proteins.[1] Publication Abstract from PubMedAsparagine-linked glycosylation is a post-translational modification of proteins containing the conserved sequence motif Asn-X-Ser/Thr. The attachment of oligosaccharides is implicated in diverse processes such as protein folding and quality control, organism development or host-pathogen interactions. The reaction is catalysed by oligosaccharyltransferase (OST), a membrane protein complex located in the endoplasmic reticulum. The central, catalytic enzyme of OST is the STT3 subunit, which has homologues in bacteria and archaea. Here we report the X-ray structure of a bacterial OST, the PglB protein of Campylobacter lari, in complex with an acceptor peptide. The structure defines the fold of STT3 proteins and provides insight into glycosylation sequon recognition and amide nitrogen activation, both of which are prerequisites for the formation of the N-glycosidic linkage. We also identified and validated catalytically important, acidic amino acid residues. Our results provide the molecular basis for understanding the mechanism of N-linked glycosylation. X-ray structure of a bacterial oligosaccharyltransferase.,Lizak C, Gerber S, Numao S, Aebi M, Locher KP Nature. 2011 Jun 15;474(7351):350-5. doi: 10.1038/nature10151. PMID:21677752[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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