CELE_F56G4.5, bam-1, F56G4.5

png-1 encodes a peptide-N[4]-(N-acetyl-beta-D-glucosaminyl) asparagine amidase (i.e., peptide:N-glycanase or PNGase) orthologous to budding yeast PNG1 and human NGLY1; PNG-1 is atypically organized, with an N-terminal thioredoxin-like domain, a central transglutaminase domain, and a C-terminal DUF750 domain, while lacking the PUB domain found in mammalian or insect PNGases; both in vitro and in vivo, PNG-1 shows both protein disulfide reductase and PNGase activities, which require its N-terminal and central domains respectively; PNG-1 has PNGase activity on denatured but not natively folded RNAse B, and releases both high mannose- and sialo-complex-type N-glycans from glycopeptides and denatured glycoproteins; in vivo, the png-1(cy8) mutation C251Y (predicted to destroy the PNGase active site) abolishes PNGase activity while leaving PNG-1's reductase activity intact; conversely, PNG-1's reductase activity is abolished by the dual missense mutation C34S/C37S, which alters its predicted N-terminal active site; by orthology, PNG-1 is expected to aid proteasomal degradation of misfolded proteins; PNG-1 activity is inhibited by Zn(2+) and the caspase inhibitor z-VAD-fmk, but not by EDTA; PNG-1 is expressed in renal gland cells and intestine; although W04G5.5 and Y50D4B.7 have some similarity to the transglutaminase domain of PNG-1, they lack a predicted catalytic triad active site.

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