1pnf

PNGASE F COMPLEX WITH DI-N-ACETYLCHITOBIOSE

spinqualitylabelsall models 1pnf, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1pnf is a 1 chain structure with sequence from Elizabethkingia meningoseptica. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2Å Ligands: NAG, NDG, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function PNGF_ELIMR Cleaves an entire glycan from a glycoprotein. Requires that the glycosylated asparagine moiety (reaction 1) be substituted on its amino (R1) and carboxyl (R2) terminus with a polypeptide chain. Publication Abstract from PubMed Crystallographic analysis and site-directed mutagenesis have been used to identify the catalytic and oligosaccharide recognition residues of peptide-N4-(N-acetyl-beta-D-glucosaminyl)asparagine amidase F (PNGase F), an amidohydrolase that removes intact asparagine-linked oligosaccharide chains from glycoproteins and glycopeptides. Mutagenesis has shown that three acidic residues, Asp-60, Glu-206, and Glu-118, that are located in a cleft at the interface between the two domains of the protein are essential for activity. The D60N mutant has no detectable activity, while E206Q and E118Q have less than 0.01 and 0.1% of the wild-type activity, respectively. Crystallographic analysis, at 2.0-A resolution, of the complex of the wild-type enzyme with the product, N,N'-diacetylchitobiose, shows that Asp-60 is in direct contact with the substrate at the cleavage site, while Glu-206 makes contact through a bridging water molecule. This indicates that Asp-60 is the primary catalytic residue, while Glu-206 probably is important for stabilization of reaction intermediates. Glu-118 forms a hydrogen bond with O6 of the second N-acetylglucosamine residue of the substrate and the low activity of the E118Q mutant results from its reduced ability to bind the oligosaccharide. This analysis also suggests that the mechanism of action of PNGase F differs from those of L-asparaginase and glycosylasparaginase, which involve a threonine residue as the nucleophile. Active site and oligosaccharide recognition residues of peptide-N4-(N-acetyl-beta-D-glucosaminyl)asparagine amidase F.,Kuhn P, Guan C, Cui T, Tarentino AL, Plummer TH Jr, Van Roey P J Biol Chem. 1995 Dec 8;270(49):29493-7. PMID:7493989 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Peptide N-glycanase

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