| abstract |
Nisin-subtilin mutant and chimeric prepeptides were constructed and expressed in a Bacillus subtilis strain that possesses all of the cellular machinery for making subtilin, except for the presubtilin gene. The chimera SL-Nis1-11-Sub12-32 was prepared. The prepeptide has the subtilin leader sequence (SL), the N-terminal portion of the structural region was derived from nisin, and the C-terminal portion of the structural region derived from subtilin. This chimera was accurately and efficiently converted to the mature lantibiotic, as demonstrated by a variety of physical and biological activity assays. In contrast, a (SL-Sub1-11-Nis12-34) chimera was processed into a heterogeneous mixture of products, none of which appeared to be the correct chimeric lantibiotic. The mixture did, however, contain an active minor component with a biological activity that exceeded nisin itself. |