THE CLONING AND NUCLEOTIDE-SEQUENCE OF THE SERINE PROTEASE GENE (ASPA) OF AEROMONAS-SALMONICIDA SSP SALMONICIDA

The gene for Aeromonas salmonicida serine protease has been cloned into phagemid pTZ18R in two restriction fragments, 2.0-kb PstI and 2.3-kb KpnI, of genomic DNA. The nucleotide sequences of the two fragments have been determined, in both directions, after subcloning, by double-stranded sequencing of nested deletions. An open reading frame of 1863 bp translated into a sequence of 621 amino acids, a 24-amino acid signal peptide and a 597-amino acid mature enzyme of molecular mass 64 173 Da. The consensus sequence, NGTS, of a serine protease substrate primary binding site was identified and a putative ribosome-binding site GGAG occurred bp upstream of the ATG initiation codon.