ExplorEnz: EC 2.4.99.21

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2.4.99.21

Accepted name:

dolichyl-phosphooligosaccharide-protein glycotransferase

Reaction:

an archaeal dolichyl phosphooligosaccharide + [protein]-L-asparagine = an archaeal dolichyl phosphate + a glycoprotein with the oligosaccharide chain attached by N-β-D-glycosyl linkage to a protein L-asparagine

Other name(s):

AglB; archaeal oligosaccharyl transferase; dolichyl-monophosphooligosaccharide-protein glycotransferase

Systematic name:

dolichyl-phosphooligosaccharide:protein-L-asparagine N-β-D-oligosaccharidotransferase

Comments:

The enzyme, characterized from the archaea Methanococcus voltae and Haloferax volcanii, transfers a glycan component from dolichyl phosphooligosaccharide to external proteins. It is different from EC 2.4.99.18, dolichyl-diphosphooligosaccharide-protein glycotransferase, which uses dolichyl diphosphate as carrier compound in bacteria and eukaryotes. The enzyme participates in the N-glycosylation of proteins in some archaea. It requires Mn²⁺. Dolichol used by archaea is different from that used by eukaryotes. It is much shorter (C₅₅-C₆₀), it is α,ω-saturated and it may have additional unsaturated positions in the chain.

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, PDB

References:

1.	Chaban, B., Voisin, S., Kelly, J., Logan, S.M. and Jarrell, K.F. Identification of genes involved in the biosynthesis and attachment of Methanococcus voltae N-linked glycans: insight into N-linked glycosylation pathways in Archaea. Mol. Microbiol. 61 (2006) 259–268. [DOI] [PMID: 16824110]
2.	Larkin, A., Chang, M.M., Whitworth, G.E. and Imperiali, B. Biochemical evidence for an alternate pathway in N-linked glycoprotein biosynthesis. Nat. Chem. Biol. 9 (2013) 367–373. [DOI] [PMID: 23624439]
3.	Cohen-Rosenzweig, C., Guan, Z., Shaanan, B. and Eichler, J. Substrate promiscuity: AglB, the archaeal oligosaccharyltransferase, can process a variety of lipid-linked glycans. Appl. Environ. Microbiol. 80 (2014) 486–496. [DOI] [PMID: 24212570]

[EC 2.4.99.21 created 2015]