| Abstract: | The genes for alkaline protease (aprBamP]) and neutral protease (nprBamP]) from Bacillus amyloliquefaciens have been isolated and expressed in Bacillus subtilis. The DNA sequences of aprBamP] and nprBamP] revealed, in each case, the presence of a large open reading frame. The inferred amino acid sequence of either gene contained a signal sequence and an additional polypeptide sequence ('pro' sequence) preceding the mature protein. Based on DNA sequence, the start point of translation has been identified as amino acid residue - 107 for aprBamP] and -221 for nprBamP]. To demonstrate that the start point of translation of aprBamP] in vivo is probably at codon -107, codon -103 (AAA) was changed to an ochre (TAA) by site-directed mutagenesis. Alkaline protease was produced from this ochre mutant derivative of aprBamP] only when the host strain was Su+. The presence of a pro sequence may be common to all of the secreted proteases from bacilli. |
