Structural Elucidation of Antibiotic TKR2999, an Antifungal Lipodepsipeptide Isolated from the Fungus <i>Foliophoma fallens</i>

• Main Authors: Gloria Crespo, Ignacio Pérez-Victoria, Francisco Javier Ortiz-López, Víctor González-Menéndez, Mercedes de la Cruz, Bastien Cautain, Pilar Sánchez, Francisca Vicente, Olga Genilloud, Fernando Reyes
• Format: Article
• Language: English
• Published: MDPI AG 2020-05-01
• Series: Antibiotics
• Subjects: <i>Foliophoma fallens</i>; antibiotic TKR2999; lipodepsipeptide; structural elucidation; Marfey’s analysis; antifungal activity
• Online Access: https://www.mdpi.com/2079-6382/9/6/278
• ISSN: 2079-6382

An antifungal lipodepsipeptide was obtained from cultures of the fungus <i>Foliophoma fallens</i> CF-236885. Its structure, elucidated by HRMS and NMR spectroscopy, contained Gly, Thr, Asn, β-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 and <i>J</i>-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 (<b>1</b>), whose non-disclosed structure was confirmed to be identical to that found for our compound, according to its physicochemical properties and NMR spectra. Compound <b>1</b> displayed potent antifungal activity against <i>Aspergillus fumigatus</i> and a panel of <i>Candida</i> strains.