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 H2O. In trifluoroethanol (TFE)/H2O (1:1, v/v) mixture, however, buforin II assumes a regular alpha-helix between residues Val(12) and Arg(20) and 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.