Molecular cloning and nucleotide sequence of the groEL gene from the alkaliphilic Bacillus sp. strain C-125 and reactivation of thermally inactivated alpha-glucosidase by recombinant GroEL.

The groEL gene of the alkaliphilic Bacillus sp. strain C-125 was cloned in Escherichia coli and sequenced. The groEL gene encoded a polypeptide of 544 amino acids and was preceded by the incomplete groES gene, lacking its 5'-end. The sequence of the derived amino acids was 87.5% identical to that of B. subtilis, 85.4% identical to that of B. stearothemophilus, and 60.9% identical to that of E. coli. The GroEL protein was expressed in E. coli. Purified GroEL protected yeast alpha-glucosidase from irreversible aggregation at a high temperature and the addition of Mg-ATP was essential for reactivation of the alpha-glucosidase. The addition of E. coli GroES increased recovery of the enzyme activity, indicating that C-125 GroEL could function in coordination with E. coli GroES.