[gmx-users] DPPC temperatur setting

[Justin A. Lemkul]

marco miele wrote:
> Hi everybody
> I am starting to analyze the membrane system composed with DPPC lipids,
> I saw  both MD membrane paper and KALP-15 tutorial to setting a 323K.
> My question is That
> in this way we working around 50 C, which is not body temperature 37 C, 
> this is not realistic approach,
> If my interest is to obtain data that respects the human body condition 
> can I to setting the temperature at 310 = 37 C or a make mistake and 
> obtain artefacts data.
> 

The reason for using 323 K in the case of DPPC is that (1) it is a common 
experimental temperature and (2) it is above the phase-transition temperature 
for this lipid.  Anywhere below 315 K or so and your membrane will enter a gel 
phase, which is not representative of the membrane properties in vivo.  Working 
with DPPC thus involves a tradeoff - you can either produce a liquid phase (like 
in vivo) or physiological temperature (while losing the physical properties 
associated with cellular membranes).  The latter is often disfavored, but the 
end result is that DPPC is simply a poor choice to represent cell membranes, but 
is often a useful in vitro model, depending on your aims and available data.

-Justin

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Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
MILES-IGERT Trainee
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin

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