ORGANIC LETTERS XXXX Plantazolicin A and B: Structure Vol. XX, No. XX Elucidation of Ribosomally Synthesized 000–000 Thiazole/Oxazole Peptides from Bacillus amyloliquefaciens FZB42 Bahar Kalyon,† Soleiman E. Helaly,†,‡ Romy Scholz,§ Jonny Nachtigall,† Joachim Vater,† Rainer Borriss,§ and Roderich D. Sussmuth*€ ,† Institut fur€ Chemie, Technische Universitat€ Berlin, 10623 Berlin, Germany, Department of Chemistry, Faculty of Science, South Valley University, Aswan 81528, Egypt, and Institute of Biology/Bakteriengenetik, Humboldt Universitat€ zu Berlin, 10115 Berlin, Germany
[email protected] Received March 28, 2011 ABSTRACT The structures of the ribosomally synthesized peptide antibiotics from Bacillus amyloliquefaciens FZB42, plantazolicin A and B, have been elucidated by high resolving ESI-MSMS, 2D 1HÀ13C-correlated NMR spectroscopy as well as 1HÀ15N-HMQC/1HÀ15N-HMBC NMR experiments. 15N-labeling prior to the experiments facilitated the structure determination, unveiling a hitherto unusual number of thiazoles and oxazoles formed from a linear 14mer precursor peptide. This finding further extends the number of known secondary metabolites from B. amyloliquefaciens and represents a new type of secondary metabolites from the genus Bacillus. The bacterium Bacillus amyloliquefaciens FZB42, which B. amyloliquefaciens was dedicated to the biosynthesis of is highly related to the Gram-positive model organism various secondary metabolites. These genes comprise the Bacillus subtilis, promotes plant growth.1 Following com- biosynthesis of nonribosomally synthesized lipocyclodep- plete sequencing and annotation of its genome,2 it was sipeptides, fengycin,3 surfactin,4 and bacillomycin5 as well found that a considerable part of the genomic DNA of as the siderophore bacillibactin.6 Likewise, based on the genomic data, genes coding for three different polyketide synthase gene clusters could be assigned to the biosynthetic † Technische Universit€at Berlin.