Solution structures by NMR of a novel antifungal drug: Petriellin A

Abstract

Petriellin A is a novel cyclic depsipeptide antifungal compound consisting of nine L-configured residues, one D-phenyllactic acid (PhLac) and three unknown chiral centres: two N-methyl-threonines (MeThr1 & MeThr2) and one N-methyl-isoleucine (MeIle). NMR experiments including 2D ROESY, NOESY along with structural and energy calculations predicted that the unknown chiral centres were all L-configured, which was later verified chemically. Simulated annealing, dynamics calculations and minimisation processes showed Petriellin A to have a folded “C-shaped” structure.