Structure and X-ray conformation of pseudodesmins A and B, two new cyclic lipodepsipeptides from Pseudomonas bacteria

Two new cyclic lipodepsipeptides named pseudodesmins A and B have been isolated from Pseudomonas bacteria collected from the mucus layer in the skin of the black belly salamander. Both compounds show moderate antibacterial activity against Gram positive bacteria, including MRSA. Complete 1H, 13C and 15N NMR assignment of both compounds afforded their covalent structure and served to guide the analysis of LC–MS and X-ray diffraction data from which the final stereochemistry could be established. Both molecules can be categorized as new members of the viscosin group of cyclic lipodepsipeptides.