Molecular cloning and nucleotide sequence of the 1,2-alpha-D-mannosidase gene, msdS, from Aspergillus saitoi and expression of the gene in yeast cells.

A full-length cDNA encoding 1,2-alpha-D-mannosidase (EC 3.2.1.113) from Aspergillus saitoi was cloned. Analysis of the 1718 bp nucleotide sequence of the cDNA revealed a single open reading frame with 1539 nucleotides of 1,2-alpha-D-mannosidase gene, msdS. The predicted amino-acid sequence of 1,2-alpha-D-mannosidase consists of 513 residues with a molecular mass of 55,767 and is 70%, 26% and 35% identity with those of Penicillium citrinum 1,2-alpha-D-mannosidase, yeast alpha-mannosidase, and mouse alpha-mannosidase. The cDNA of the msdS gene has been cloned and expressed in yeast cells. To identify the activity of expression product methyl-2-O-alpha-mannopyranosyl-alpha-mannopyranoside (Man alpha 1-->2Man-OMe) was used as a substrate at pH 5.0.