2i74 | pdb_00002i74
Crystal structure of mouse Peptide N-Glycanase C-terminal domain in complex with mannopentaose
Structural highlights
Function[NGLY1_MOUSE] Specifically deglycosylates the denatured form of N-linked glycoproteins in the cytoplasm and assists their proteasome-mediated degradation. Cleaves the beta-aspartyl-glucosamine (GlcNAc) of the glycan and the amide side chain of Asn, converting Asn to Asp. Prefers proteins containing high-mannose over those bearing complex type oligosaccharides. Can recognize misfolded proteins in the endoplasmic reticulum that are exported to the cytosol to be destroyed and deglycosylate them, while it has no activity toward native proteins. Deglycosylation is a prerequisite for subsequent proteasome-mediated degradation of some, but not all, misfolded glycoproteins.[1] [2] [3] 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 PubMedThe inability of certain N-linked glycoproteins to adopt their native conformation in the endoplasmic reticulum (ER) leads to their retrotranslocation into the cytosol and subsequent degradation by the proteasome. In this pathway the cytosolic peptide-N-glycanase (PNGase) cleaves the N-linked glycan chains off denatured glycoproteins. PNGase is highly conserved in eukaryotes and plays an important role in ER-associated protein degradation. In higher eukaryotes, PNGase has an N-terminal and a C-terminal extension in addition to its central catalytic domain, which is structurally and functionally related to transglutaminases. Although the N-terminal domain of PNGase is involved in protein-protein interactions, the function of the C-terminal domain has not previously been characterized. Here, we describe biophysical, biochemical, and crystallographic studies of the mouse PNGase C-terminal domain, including visualization of a complex between this domain and mannopentaose. These studies demonstrate that the C-terminal domain binds to the mannose moieties of N-linked oligosaccharide chains, and we further show that it enhances the activity of the mouse PNGase core domain, presumably by increasing the affinity of mouse PNGase for the glycan chains of misfolded glycoproteins. Structural and biochemical studies of the C-terminal domain of mouse peptide-N-glycanase identify it as a mannose-binding module.,Zhou X, Zhao G, Truglio JJ, Wang L, Li G, Lennarz WJ, Schindelin H Proc Natl Acad Sci U S A. 2006 Nov 14;103(46):17214-9. Epub 2006 Nov 6. PMID:17088551[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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