|Gene:||ALG3||Accession Number: G-5581 (MetaCyc)|
Species: Saccharomyces cerevisiae
Sequence analysis of the ALG3 protein product suggested a transmembrane protein containing 10 potential transmembrane helices. Endoplasmic reticulum location was suggested by the C-terminal sequence motif KKLN [Aebi96].
ALG3 mutants accumulate (mannosyl)5-(N-acetylglucosaminyl)2-diphosphodolichol [Huffaker83, Verostek91].
Gene Citations: [Sharma01]
Locations: endoplasmic reticulum
|Map Position: [69,748 <- 71,124]|
Molecular Weight of Polypeptide: 53.4 kD (from nucleotide sequence)
|Cellular Component:||GO:0005783 - endoplasmic reticulum [Aebi96]|
Enzymatic reaction of: Dol-P-Man:Man5GlcNAc2-PP-Dol mannosyltransferase
EC Number: 188.8.131.528
The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the Enzyme Commission system.
The reaction is favored in the direction shown.
In Pathways: dolichyl-diphosphooligosaccharide biosynthesis
ALG3 mutants accumulated (mannosyl)5-(N-acetylglucosaminyl)2-diphosphodolichol [Huffaker83, Verostek91]. Mannosyl transfer specifically to (mannosyl)5-(N-acetylglucosaminyl)2-diphosphodolichol by this enzyme was shown. This reaction was shown to be independent of divalent cations. After immunoprecipitation of the ALG3 protein, it was shown to exclusively catalyze the conversion of (mannosyl)5-(N-acetylglucosaminyl)2-diphosphodolichol to (mannosyl)6-(N-acetylglucosaminyl)2-diphosphodolichol [Sharma01].
Sharma01: Sharma CB, Knauer R, Lehle L (2001). "Biosynthesis of lipid-linked oligosaccharides in yeast: the ALG3 gene encodes the Dol-P-Man:Man5GlcNAc2-PP-Dol mannosyltransferase." Biol Chem 382(2);321-8. PMID: 11308030
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