The role of d-allo-isoleucine in the deposition of the anti-Leishmania peptide bombinin H4 as revealed by P solid-state NMR, VCD spectroscopy, and MD simulation.

Bombinin H4 is an antimicrobial peptide that was isolated from the toad Bombina variegata. Bombinin H family peptides are active against gram-positive, gram-negative bacteria, and fungi as well as the parasite Leishmania. Among them, bombinin H4 (H4), which contains d-allo-isoleucine (d-allo-Ile) as the second residue in its sequence, is the most active, and its l-isomer is bombinin H2 (H2).