CLONING AND NUCLEOTIDE-SEQUENCE OF THE BGLA GENE FROM ERWINIA-HERBICOLA AND EXPRESSION OF BETA-GLUCOSIDASE ACTIVITY IN ESCHERICHIA-COLI

Genomic DNA fragments encoding beta-glucosidase activity from the wild-type strain WD4 of Erwinia herbicola were cloned into Escherichia coli. Two clones containing a common fragment encoded a polypeptide of 58 000 Da. Cloned beta-glucosidase, expressed in E. coli, showed activity against natural beta-glucoside sugars except for cellobiose. An open reading frame of 1442 bp termed bglA was identified by nucleotide sequencing and it coded for a protein of 480 amino acids (M(r) 53 896) which showed significant homology with beta-glucosidases from glycosyl hydrolase family 1.