Cloning and sequencing of an endoglucanase gene from Scopulariopsis brevicaulis TOF-1212, and its expression in Saccharomyces cerevisiae

The egI gene, encoding a major endoglucanase (EGI) of Scopulariopsis brevicaulis TOF-1212, was cloned and sequenced. The egI gene consisted of 868 bp with one intron and encoded a protein of 229 amino acids with a calculated molecular mass of 22,392 daltons. The EGI was assigned to a family 45 of glycosyl hydrolases and showed high similarity with other fungal endoglucanases, especially with those of Humicola grisea and Fusarium oxysporum, on the basis of hydrophobic cluster analysis. The egI gene was expressed under the promoter of the phosphoglycerate kinase gene (PGK) in Saccharomyces cerevisiae. The transformed cells were able to secrete the enzyme efficiently in an active form.