Abstract
This paper reports all-atom computer simulations of five phospholipid
membranes, DMPC, DPPC, DMPG, DMPS, and DMPSH, with a focus
on the thermal equilibrium fluctuations of volume, energy, area, thickness,
and order parameter. For the slow fluctuations at constant temperature
and pressure (defined by averaging over 0.5 nanosecond) volume and energy
exhibit strong correlation. These quantities on the other hand do not
correlate significantly with area, thickness, or order parameter. The correlations
are mainly reported for the fluid phase, but we also give results for
the ordered (gel) phase of two membranes, showing a similar picture. The
cause of the observed strong correlations is identified by splitting volume
and energy into contributions from tails, heads, and water, showing that
the slow volume-energy fluctuations derive from the tail region’s van der
Waals interactions and are thus analogous the similar strong correlations
recently observed in computer simulations of the Lennard-Jones and other
simple van der Waals type liquids. The strong correlations reported here
confirm an assumption of a recent theory for nerve signal propagation
proposed by Heimburg and Jackson (2005).
Original language | English |
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Journal | Arxiv.org: Physics |
Volume | arXiv:0811.3317v1 |
Number of pages | 16 |
Publication status | Published - 2008 |