Conformation of the Cecropin-Melittin Hybrid, Cecropin A(1-8)-Melittin (1-18) Antibacterial Peptide

Cecropin A (1-8)-Melittin (1-18) is a synthetic cecropin A-melittin hybrid peptide with leishmanicidal activity. The primary sequence of the peptide is as follows: KWKLPKKIGIGAVLKVLTTGLPALIS-NH2. 1H and 13C 2D NMR techniques were used to deduce the conformational parameters of chemical shift, 3JNHα coupling constants, temperature coefficients of NH chemical shifts and the pattern of intra and inter-residue nOe's. NMR studies were carried out in water (pH 6.0) and hexafluoroacetone (HFA). The peptide was found in a β-pleated structure in water, and in HFA it adopts a right-handed α-helix conformation. Solution structures generated using restrained molecular dynamics simulations were refined by Mardigras to R factors ranging from 0.5 to 0.6.