Neutron reflection implication of novel serine-rich antimicrobial peptides killing bacteria

Alteration of antimicrobial peptides’ (AMPs) relative charge and hydrophobicity affects their self-association, self-assembly and subsequent interaction with bacterial membranes. Herein, we designed novel AMPs containing serine amino acids, to discover how substituting lysine residues for serine influences peptide association and membrane binding compared to a control peptide G(IIKK)3-NH₂ (G3), with proven antimicrobial potency [1]. AMP antimicrobial abilities are explored with a typical Gram-negative E. coli bacterial inner membrane mimic of POPC/POPG (7:3). Coarse-grained molecular dynamics (MD) simulations reveal peptides with higher serine content tend to form larger aggregates and bind to the membrane as oligomers, forming various intramembrane aggregates. Experimental data from dual polarisation interferometry (DPI) along with MD simulations have placed us in a solid position to undertake neutron reflection (NR) to unravel how these AMPs interact with a model membrane at molecular level.