CLONING AND SEQUENCE OF AN ALKALINE SERINE PROTEASE-ENCODING GENE FROM THE MARINE BACTERIUM ALTEROMONAS SP STRAIN O-7

The gene (aprII) encoding alkaline serine protease (April; subtilase) from Alteromonas sp. strain O-7 was cloned in plasmid pUC19 and transformed into Escherichia coli JM109. The nucleotide (nt) sequence of aprII has been determined. A single open reading frame (ORF) encoded a protein consisting of 621 amino acids (aa) with a M(r) of 63958. The results of aa sequence analysis indicated that April is produced as a large precursor consisting of four domains: the signal sequence, the N-terminal pro-region (AprII-N), the mature April (AprII-M) and the C-terminal pro-region (AprII-C). The aa sequence of AprII-M shows high sequence homology with those of class-II subtilases. Two conserved sequences were found in AprII-N which might play a critical role in the maintenance of chaperone-like activity. Repeated aa sequences were observed in AprII-C (AprII-C1 and AprII-C2). The aa sequences of AprII-C1 and AprII-C2 show high sequence homology with those of the C-terminal pro-region of the other known proteases.