Bacillus intermedius glutamyl endopeptidase. Molecular cloning and nucleotide sequence of the structural gene

The glutamyl endopeptidase gene of Bacillus intermedius was cloned from a genomic library expressed in Bacillus subtilis and sequenced (EMBL accession number Y15136). The encoded preproenzyme contains 303 amino acid residues; the mature 23-kDa enzyme consists of 215 residues. The mature enzyme reveals 38% of identical residues when aligned with the glutamyl endopeptidase from Bacillus licheniformis, whereas only five invariant residues were found among all known glutamyl endopeptidases. The amino acid residues that form the catalytic triad (H47, D98, and S171) as well as H186 participating in the binding of the substrate carboxyl group were identified. It seems that the structural elements responsible for the function of glutamyl endopeptidases from various sources are highly variable.