Elucidation of sevadicin, a novel non‐ribosomal peptide secondary metabolite produced by the honey bee pathogenic bacterium Paenibacillus larvae

• Published in: Environmental microbiology 2014-05, Vol.16 (5), p.1297-1309
• Main Authors: Garcia‐Gonzalez, Eva, Müller, Sebastian, Ensle, Paul, Süssmuth, Roderich D, Genersch, Elke
• Format: Article
• Language: English
• Subjects: American foul brood; Animal, plant and microbial ecology; Animals; Anti-Bacterial Agents - chemistry; Anti-Bacterial Agents - metabolism; Anti-Bacterial Agents - pharmacology; antibacterial properties; Apis mellifera; Apoidea; Bacillus megaterium - drug effects; Bacillus megaterium - growth & development; Bacillus subtilis - drug effects; Bacillus subtilis - growth & development; Bacteria; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - metabolism; Bacteriology; Bees; Bees - microbiology; Biological and medical sciences; enantiomers; Enzymes; Fundamental and applied biological sciences. Psychology; General aspects; Genomes; Genotype; honey bees; Host-Pathogen Interactions; knockout mutants; Larva - microbiology; larvae; ligases; mass spectrometry; Microbial ecology; Microbiology; Miscellaneous; Multigene Family; Oligopeptides - chemistry; Oligopeptides - genetics; Oligopeptides - metabolism; Oligopeptides - pharmacology; Paenibacillus - genetics; Paenibacillus - metabolism; Paenibacillus - pathogenicity; Paenibacillus larvae; Peptide Library; secondary metabolites; synthesis
• ISSN: 1462-2912; 1462-2920
• DOI: 10.1111/1462-2920.12417

American foulbrood (AFB) caused by the bee pathogenic bacterium Paenibacillus larvae is the most devastating bacterial disease of honey bees worldwide. From AFB‐dead larvae, pure cultures of P. larvae can normally be cultivated indicating that P. larvae is able to defend its niche against all other bacteria present. Recently, comparative genome analysis within the species P. larvae suggested the presence of gene clusters coding for multi‐enzyme complexes, such as non‐ribosomal peptide synthetases (NRPSs). The products of these enzyme complexes are known to have a wide range of biological activities including antibacterial activities. We here present our results on antibacterial activity exhibited by vegetative P. larvae and the identification and analysis of a novel antibacterially active P. larvae tripeptide (called sevadicin; Sev) produced by a NRPS encoded by a gene cluster found in the genome of P. larvae. Identification of Sev was ultimately achieved by comparing the secretome of wild‐type P. larvae with knockout mutants of P. larvae lacking production of Sev. Subsequent mass spectrometric studies, enantiomer analytics and chemical synthesis revealed the sequence and configuration of the tripeptide, D‐Phe‐D‐ALa‐Trp, which was shown to have antibacterial activity. The relevance of our findings is discussed in respect to host–pathogen interactions.