The effect of amidation on the behaviour of antimicrobial peptides

Aurein 2.6-COOH and aurein 3.1-COOH were studied along with their naturally occurring C-terminally amidated analogues. Circular dichroism (CD) and molecular dynamic (MD) simulations were used to study the effects of amidation on the interaction of antimicrobial peptides (AMPs) with lipid bilayers. CD measurements and MD analysis suggested that both peptide analogues were predominantly random coil and adopted low levels of [Formula: see text] -helical structure in solution (<30 %) and in the presence of a lipid bilayer the peptides formed a stable [Formula: see text] -helical structure. In general, amidated analogues have a greater propensity than the non-amidated peptides to form a [Formula: see text] -helical structure. MD simulations predicted that aurein 2.6-COOH and aurein 3.1-CHOOH destabilised lipid bilayers from 1,2-dimyristoyl-sn-glycero-3-phosphocholine and 1,2-dimyristoyl-sn-glycero-3-phosphoserine via angled bilayer penetration. They also showed that aurein 2.6-CONH[Formula: see text] and aurein 3.1-CONH[Formula: see text] formed a helix horizontal to the plane of an asymmetric interface. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00249-015-1094-x) contains supplementary material, which is available to authorized users.