CLONING AND EXPRESSION OF AN AEROMONAS-HYDROPHILA CHITINASE GENE IN ESCHERICHIA-COLI

The gene encoding an extracellular chitinase from Aeromonas hydrophila has been cloned and expressed in Escherichia coli. Plasmid pJP2512 contained the smallest DNA insert (3.9 kb) producing chitinase. The chitinase gene is transcribed from its own promoter, producing a protein of M(r) 96,000. The chitinase open reading frame, an estimated 2.6 kb in length, has been subcloned to a 3.0 kb fragment; however, this fragment does not carry the functional chitinase promoter. In E. coli the chitinase enzyme is unable to transverse the outer membrane, being secreted across the cytoplasmic membrane and accumulating in the periplasmic space.