2zag | pdb_00002zag
Crystal structure of the SeMet-substituted soluble domain of STT3 from P. furiosus
Structural highlights
FunctionAGLB1_PYRFU Oligosaccharyl transferase (OST) that catalyzes the initial transfer of a defined glycan (ManNAcXyl(2)GlcAMan(2)GalNAc in P.furiosus) from the lipid carrier dolichol-monophosphate to an asparagine residue within an Asn-X-Ser/Thr consensus motif in nascent polypeptide chains, the first step in protein N-glycosylation.[1] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedAsn-glycosylation is widespread not only in eukaryotes but also in archaea and some eubacteria. Oligosaccharyltransferase (OST) catalyzes the co-translational transfer of an oligosaccharide from a lipid donor to an asparagine residue in nascent polypeptide chains. Here, we report that a thermophilic archaeon, Pyrococcus furiosus OST is composed of the STT3 protein alone, and catalyzes the transfer of a heptasaccharide, containing one hexouronate and two pentose residues, onto peptides in an Asn-X-Thr/Ser-motif-dependent manner. We also determined the 2.7-A resolution crystal structure of the C-terminal soluble domain of Pyrococcus STT3. The structure-based multiple sequence alignment revealed a new motif, DxxK, which is adjacent to the well-conserved WWDYG motif in the tertiary structure. The mutagenesis of the DK motif residues in yeast STT3 revealed the essential role of the motif in the catalytic activity. The function of this motif may be related to the binding of the pyrophosphate group of lipid-linked oligosaccharide donors through a transiently bound cation. Our structure provides the first structural insights into the formation of the oligosaccharide-asparagine bond. Structure-guided identification of a new catalytic motif of oligosaccharyltransferase.,Igura M, Maita N, Kamishikiryo J, Yamada M, Obita T, Maenaka K, Kohda D EMBO J. 2008 Jan 9;27(1):234-43. Epub 2007 Nov 29. PMID:18046457[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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