Biosynthesis of the lantibiotic mersacidin: Organization of a type B lantibiotic gene cluster

The biosynthetic gene cluster (12.3 kb) of mersacidin, a lanthionine-contai ning antimicrobial peptide, is located on the chromosome of the producer, B acillus sp, strain HIL Y-85,54728 in a region that corresponds to 348 degre es on the chromosome of Bacillus subtilis 168, It consists of 10 open readi ng frames and contains, in addition to the previously described mersacidin structural gene mrsA (G. Bierbaum, H. Brotz, K.-P, Koller, and H.-G. Sahl, FEMS Microbiol, Lett. 127:121-126, 1995), two genes, mrsM and mrsD, coding for enzymes involved in posttranslational modification of the prepeptide; o ne gene, mrsT, coding for a transporter with an associated protease domain; and three genes, mrsF, mrsG, and mrsE, encoding a group Il ABC transporter that could be involved in producer self-protection. Additionally, three re gulatory genes are part of the gene cluster, i.e., mrsR2 and mrsK2, which e ncode a two-component regulatory system which seems to be necessary for the transcription of the mrsFGE operon, and mrsR1, which encodes a protein wit h similarity to response regulators. Transcription of mrsA sets in at early stationary phase (between 8 and 16 h of culture).