Molecular Dynamics Simulations of Indolicidin Association with Model Lipid Bilayers
Jenny C.Y. Hsu 1 and Christopher M Yip 1*
1 University of Toronto
* To whom correspondence should be addressed. E-mail: christopher.yip{at}utoronto.ca.
Submitted on March 3, 2007
Revised on March 26, 2007
Accepted on 3 April 2007
 |
Abstract |
|---|
Identifying the mechanisms responsible for the interaction of peptides with cell membranes is critical to the design of new antimicrobial peptides and membrane transporters. We report here the results of a computational simulation of the interaction of the 13-residue peptide indolicidin with single-phase lipid bilayers of dioleoylphosphatidylcholine (DOPC), distearoylphosphatidylcholine (DSPC), dioleoylphosphatidylglycerol (DOPG) and distearoylphosphatidylglycerol (DSPG). Ensemble analysis of the membrane-bound peptide revealed that, in contrast to the extended, linear backbone structure reported for indolicidin in SDS detergent micelles, the peptide adopts a boat-shaped conformation in both PG and PC lipid bilayers, similar to that reported for DPC micelles. In agreement with fluorescence and NMR experiments, simulations confirmed that the peptide localizes in the membrane interface, with the distance between phosphate headgroups of each leaflet being reduced in the presence of indolicidin. These data, along with a concomitant decrease in lipid order parameters for the upper-tail region, suggests that indolicidin binding results in membrane thinning, consistent with recent in situ atomic force microscopy studies
Key Words:
Antimicrobial peptides, Lipid bilayer, Molecular dynamics, Peptide-membrane interactions
