Beta hairpin peptides induced membrane perturbations in the liposomes: A charge-based interaction study

Monday, October 24, 2011 — Poster Session I
Noon – 2:00 p.m.	Natcher Conference Center	NCI	BIOPHY-4

Authors

• K Gupta
• K Harlen
• M Branco
• A Puri
• J Schneider
• R Blumenthal

Abstract

Several peptides with different structural conformations have been investigated to understand their mechanism of action in perturbing biological membranes using liposomes as a model system. In the present investigation, we are exploring the membrane destabilizing properties of novel amphiphilic positively charged beta-hairpin peptides, Max1 and Max351. We have studied peptide folding (CD measurements) and peptide-induced solute release (Tb/DPA leakage assay) as a function charge on the liposomes. We report that both peptides Max1 and Max35 promote solute release from negatively charged liposomes (containing a mixture of a neutral phospholipid (POPC) and a negatively charged phospholipid lipid (POPS). Similarly, peptide folding was also dependent on the negative charge in the liposomes. The extent of Tb/DPA leakage by peptides was dependent on the % of POPS in the liposomes for both Max1 and Max35. Interestingly, higher concentrations of Max1 were needed to induce same amount of leakage. A control peptide, MAXV18E did not fold and also failed to promote solute release under identical conditions. These studies present a model system for elucidating the mechanism of interaction of beta hairpin peptides with the lipid bilayer and their subsequent use in drug delivery. Ref 1. Rajagopal K et al. Biomacromolecules. 2009 Sep 14;10(9):2619-25.

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