Solution structure of an antimicrobial peptide buforin II

The structure of 21-residue antimicrobial peptide buforin II has been determined by using NMR spectroscopy and restrained molecular dynamics. Buforin II adopts a flexible random structure in H 2O. In trifluoroethanol (TFE)/H 2O (1 : 1, v/v) mixture, however, buforin II assumes a regular α-helix between residues Val 12 and Arg 20 and a distorted helical structure between residues Gly 7 and Pro 11. The model structure obtained shows an amphipathic character in the region from Arg 5 to the C-terminus, Lys 21. Like other known cationic antimicrobial peptides, the amphipathic structure might be the key factor for antimicrobial activity of buforin II.