Abstract
Bacillus sp. 11-4 metalloprotease (protease I), which shows collagenase-like specificity, was purified from the culture supernatant of the strain. The N-terminal amino acid sequence of the protease I was determined up to 43 residues from its N-terminus. Further, five derivative peptides were obtained by V 8 protease digestion and their amino acid sequences were analyzed. Of the fragments, three derivatives showed identical N-terminal sequence with the parent protease I. On the other hand, the remaining two derivatives showed sequences, which seemed to match the internal region of parent protease I. Adapting the partial amino acid sequence information to a BLAST database search, the protease I showed significant similarity with the neutral metalloproteases, which possess the zincbinding motif HEXXH, produced by some clostridia, bacilli, streptococci and staphylococci. The listed metalloproteases commonly possessed the hidden Markov model domain for thermolysin family protease. The functional features of the protease I determined previously, such as molecular masses, isoelectric points and pH optimums, showed agreement with those of thermolysin family proteases. Consequently the partial amino acid sequence analysis suggests that the protease I is defined as a thermolysin-like metalloprotease.
