Cloning and expression of protease genes from Treponema denticola in Escherichia coli

A gene bank of random fragments of chromosomal DNA from Treponema denticola ATCC 33520 was constructed in the bacteriophage vector lambda L47.1. The gene bank was plated on Escherichia coli C600 and screened for the presence of plaques in which enzyme activity was expressed, using overlays of fluorogenic synthetic substrates and a two-step procedure in which immunological screening was followed by enzyme assays of immunopositive lysates. Recombinants expressing trypsin-like, chymotrypsin-like and proline iminopeptidase activities were found. The gene for the trypsin-like activity was subcloned into plasmid pJDC9 and maintained in E. coli.