Structural Elucidation of Antibiotic TKR2999, an Antifungal Lipodepsipeptide Isolated from the Fungus Foliophoma fallens .

An antifungal lipodepsipeptide was obtained from cultures of the fungusFoliophoma fallensCF-236885. Its structure, elucidated by HRMS and NMR spectroscopy, contained Gly, Thr, Asn, beta-Ala, Orn, Ala, two Ser residues, and 3-hydroxy-4-methylhexadecanoic acid. The absolute configuration of its amino acid residues was determined using Marfey's analysis andJ-based configuration analysis helped to establish the relative configuration of the 3-hydroxy-4-methylhexadecanoic acid moiety. A literature search retrieved a patent describing antibiotic TKR2999 (1), whose non-disclosed structure was confirmed to be identical to that found for our compound, according to its physicochemical properties and NMR spectra. Compound1displayed potent antifungal activity againstAspergillus fumigatusand a panel ofCandidastrains.