Biosynthesis of the Lantibiotic Mersacidin: Organization of a Type B Lantibiotic Gene Cluster

Abstract

ABSTRACT The biosynthetic gene cluster (12.3 kb) of mersacidin, a lanthionine-containing antimicrobial peptide, is located on the chromosome of the producer, Bacillus sp. strain HIL Y-85,54728 in a region that corresponds to 348° on the chromosome of Bacillus subtilis 168. It consists of 10 open reading frames and contains, in addition to the previously described mersacidin structural gene mrsA (G. Bierbaum, H. Brötz, 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; one gene, mrsT , coding for a transporter with an associated protease domain; and three genes, mrsF , mrsG , and mrsE , encoding a group B ABC transporter that could be involved in producer self-protection. Additionally, three regulatory genes are part of the gene cluster, i.e., mrsR2 and mrsK2 , which encode a two-component regulatory system which seems to be necessary for the transcription of the mrsFGE operon, and mrsR1 , which encodes a protein with similarity to response regulators. Transcription of mrsA sets in at early stationary phase (between 8 and 16 h of culture).