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 presented.)-helical structure in solution (<30 %) and in the presence of a lipid bilayer the peptides formed a stable (Formula presented.)-helical structure. In general, amidated analogues have a greater propensity than the non-amidated peptides to form a (Formula presented.)-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 presented.) and aurein 3.1-CONH(Formula presented.) formed a helix horizontal to the plane of an asymmetric interface. © 2016 The Author(s)