Cerecidins, novel lantibiotics from Bacillus cereus with potent antimicrobial activity.

Applied and environmental microbiology

PubMedID: 24532070

Wang J, Zhang L, Teng K, Sun S, Sun Z, Zhong J. Cerecidins, novel lantibiotics from Bacillus cereus with potent antimicrobial activity. Appl Environ Microbiol. 2014;.
Lantibiotics are ribosomally-synthesized and posttranslationally-modified antimicrobial peptides, which are widely produced by Gram-positive bacteria including many species of Bacillus group. In present study, one novel gene cluster coding lantibiotics cerecidins was unveiled in B. cereus As 1.1846 through genomic mining and PCR screening. The designated cer locus is different from that of conventional class II lantibiotics in that it included seven tandem precursor genes cerAs, one modification gene cerM, two processing genes cerT and cerP, one orphan regulator gene cerR and two immunity genes cerF and cerE. In addition, one unprecedented quorum sensing component comQXPA was inserted between cerM and cerR. The expression of cerecidins was not detected in this strain of B. cereus, which might be due to repressed transcription of cerM. We constitutively coexpressed cerAs and cerM in Escherichia coli and purified pre-cerecidins were proteolytically processed with the endoproteinase GluC and a truncated version of putative serine protease CerP. Thus, two natural variants of cerecidins A1 and A7 were obtained which contained two terminal non-overlapping thioether rings rarely found in lantibiotics. Both cerecidin A1 and A7 were active against a broad spectrum of Gram-positive bacteria. The cerecidin A7, especially its mutant Dhb13A, showed remarkable efficacy against multidrug-resistant Staphylococcus aureus (MDRSA), vancomycin-resistant Enterococcus faecalis (VRE) and even Streptomyces.