title: The cooperative behaviour of antimicrobial peptides in model membranes.
abstract: A systematic analysis of the hypothesis of the antimicrobial peptides' (AMPs) cooperative action is performed by means of full atomistic molecular dynamics simulations accompanied by circular dichroism experiments. Several AMPs from the aurein family (2.5,2.6, 3.1), have a similar sequence in the first ten amino acids, are investigated in different environments including aqueous solution, trifluoroethanol (TFE), palmitoyloleoylphosphatidylethanolamine (POPE), and palmitoyloleoylphosphatidylglycerol (POPG) lipid bilayers. It is found that the cooperative effect is stronger in aqueous solution and weaker in TFE. Moreover, in the presence of membranes, the cooperative effect plays an important role in the peptide/lipid bilayer interaction. The action of AMPs is a competition of the hydrophobic interactions between the side chains of the peptides and the hydrophobic region of lipid molecules, as well as the intra peptide interaction. The aureins 2.5-COOH and 2.6-COOH form a hydrophobic aggregate to minimize the interaction between the hydrophobic group and the water. Once that the peptides reach the water/lipid interface the hydrophobic aggregate becomes smaller and the peptides start to penetrate into the membrane. In contrast, aurein 3.1-COOH forms only a transient aggregate which disintegrates once the peptides reached the membrane, and it shows no cooperativity in membrane penetration.
authors.affiliation: UCLan Biomedical Technology Ltd (Shenzhen), Shenzhen Virtual University Park, Shenzhen 518057, PR China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Wang
authors.affiliation: Computational Physics Group, University of Central Lancashire, Preston PR1 2HE, UK; Institute for Nanotechnology and Bioengineering, University of Central Lancashire, Preston PR1 2HE, UK.
authors.forename: Manuela
authors.initials: M
authors.lastname: Mura
authors.affiliation: UCLan Biomedical Technology Ltd (Shenzhen), Shenzhen Virtual University Park, Shenzhen 518057, PR China.
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Computational Physics Group, University of Central Lancashire, Preston PR1 2HE, UK; Institute for Nanotechnology and Bioengineering, University of Central Lancashire, Preston PR1 2HE, UK. Electronic address: mpinna.uclan@gmail.com.
authors.forename: Marco
authors.initials: M
authors.lastname: Pinna
authors.affiliation: Computational Physics Group, University of Central Lancashire, Preston PR1 2HE, UK; Institute for Nanotechnology and Bioengineering, University of Central Lancashire, Preston PR1 2HE, UK.
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Zvelindovsky
authors.affiliation: Institute for Nanotechnology and Bioengineering, University of Central Lancashire, Preston PR1 2HE, UK.
authors.forename: Sarah R
authors.initials: SR
authors.lastname: Dennison
authors.affiliation: Institute for Nanotechnology and Bioengineering, University of Central Lancashire, Preston PR1 2HE, UK.
authors.forename: David A
authors.initials: DA
authors.lastname: Phoenix
keywords: Amino acid; Antimicrobial peptide; Cooperative effect; Membrane; Molecular dynamics; Secondary structure