Isolation and characterization of a new iturinic lipopeptide, mojavensin A produced by a marine-deriived bacterium Bacillus mojavensis B0621A

Three lipopeptides were isolated by bioactivity-guided fractionation from the fermentation broth of Bacillus mojavensis B0621A. A new iturinic lipopeptide, named mojavensin A (1), was tentatively characterized by 1D, 2D NMR and MS spectroscopy, Marfey's method containing a novel peptide backbone of L-Asn(1), D-Tyr(2), D-Asn(3), L-Gln(4), L-Pro(5), D-Asn(6), L-Asn(7) and an anteiso-type of the saturated beta-fatty acid side chain. Compound 2 and 3 were tentatively identified as iso-C16 fengycin B and anteiso-C17 fengycin B, respectively. These lipopeptides displayed dose-dependent antifungal activity against a broad spectra of phytopathogens and were weakly antagonistic to Staphylococcus aureus. Moreover, they all revealed cytotoxic activities against the human leukemia (HL-60) cell line. Mojavensin A, iso-C16 fengycin B, and anteiso-C17 fengycin B inhibited the growth of HL-60 with IC50 of 100, 100 and 1.6 mu M, respectively. The Journal of Antibiotics (2012) 65, 317-322; doi:10.1038/ja.2012.19; published online 11 April 2012