2003/12/16 by Andrey A. Gurtovenko, A. A. Gurtovenko, Michael Patra +2 · 1 citation
Biochemistry, Genetics and Molecular Biology · Chemistry · Engineering · Physics and Astronomy · #Bilayer #Biochemistry #Cationic polymerization #Chemical physics #Chemistry #Computational chemistry #Crystallography #Electrostatics #Ion #Lipid Membrane Structure and Behavior #Lipid bilayer #Lipid bilayer phase behavior #Membrane #Mole fraction #Molecular dynamics #Nanopore and Nanochannel Transport Studies #Organic chemistry #Physical chemistry #RNA Interference and Gene Delivery #cond-mat.soft #physics.bio-ph #q-bio.BM
paper · pdf · doi:10.1529/biophysj.103.038760
arxiv created 2003/12/16 · openalex publication_date 2004/06/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Cationic lipid membranes are known to form compact complexes with DNA and to be effective as gene delivery agents both in vitro and in vivo. Here we employ molecular dynamics simulations for a detailed atomistic study of lipid bilayers consisting of a mixture of cationic dimyristoyltrimethylammonium propane (DMTAP) and zwitterionic dimyristoylphosphatidylcholine (DMPC). Our main objective is to examine how the composition of the bilayers affects their structural and electrostatic properties in the liquid-crystalline phase. By varying the mole fraction of DMTAP, we have found that the area per lipid has a pronounced non-monotonic dependence on the DMTAP concentration, with a minimum around the point of equimolar mixture. We show that this behavior has an electrostatic origin and is driven by the interplay between positively charged TAP headgroups and the zwitterionic PC heads. This interplay leads to considerable re-orientation of PC headgroups for an increasing DMTAP concentration, and gives rise to major changes in the electrostatic properties of the lipid bilayer, including a significant increase of total dipole potential across the bilayer and prominent changes in the ordering of water in the vicinity of the membrane. Moreover, chloride counter-ions are bound mostly to PC nitrogens implying stronger screening of PC heads by Cl ions compared to TAP head groups. The implications of these findings are briefly discussed.