Paper Citing NAMD - Abstract
Lim, Joseph B.; Klauda, Jeffery B.
Lipid chain branching at the iso- and anteiso-positions in complex chlamydia membranes: A molecular dynamics study
BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES, 1808:323-331, JAN 2011
Membranes in the intracellular eubacterial parasite Chlamydia trachomatis consist of the elementary body (EB) and reticular body (RB), and contain methyl branches at the iso- and anteiso-positions for some phospholipid chains. Acyl chain branching is the focus of this study. Molecular dynamics simulations were used to study bilayers of 1-13-methylpentadecanoyl-2-palmitoyl-phosphatidylcholine (13-MpPPC), 1-14-methylpentadecanoyl-2-palmitoyl-phosphatidylcholine (14-MpPPC), and diphytanoylphosphatidylcholine (DPhPC). These three membranes were simulated at 323 K and simulations of DPhPC at 298 K were also performed for better comparison to existing experimental data. Two simulations of representative EB and RB membranes of C. trachomatis composed of nine different lipid components were performed at 310.15 K, to accurately reflect compositions determined by experiment and physiological conditions. Based on nearly 0.5 mu s of simulation data, we report that branching increases average lipid surface area, area elastic moduli, and lipid axial relaxation times, while decreasing lipid chain order. Branching also has a distinct effect on electron density profiles. Due to their high cholesterol concentrations, the EB and RB membranes were found to have relatively high area elastic moduli, which may have important biological implications. (C) 2010 Elsevier B.V. All rights reserved.
