Re: [AMBER] Simulating lipid bilayer below phase transition temperature

From: Dickson, Callum J <callum.dickson09.imperial.ac.uk>
Date: Mon, 23 Jan 2017 22:37:52 +0000

Hi,


Simulation of PC/Chol mixtures is possible using the recently derived parameters for cholesterol which have been validated in this paper:


http://pubs.acs.org/doi/full/10.1021/acs.jpcb.6b01870


Phase behaviour of lipids using Lipid14 has not been extensively studied and melting points etc were not used as target data during derivation of the force field. A recent paper found that the melting point of DPPC using Lipid14 was somewhat over-estimated:


http://pubs.acs.org/doi/full/10.1021/acs.jpcb.6b01870


If I understand correctly, you would like to model a DPPC/Chol system in the gel phase (ie below the phase transition to liquid crystalline)?


I would suggest first running DPPC/Chol mixtures at different temperatures and ensure that it is in the correct phase that you wish to simulate, bearing in mind the melting point of the system may not match experiment.


Callum

________________________________
From: Casalini Tommaso <tommaso.casalini.chem.ethz.ch>
Sent: Monday, January 23, 2017 5:12:24 PM
To: amber.ambermd.org
Subject: [AMBER] Simulating lipid bilayer below phase transition temperature

Dear Amber users and developers,
I need to simulate a DPPC/Cholesterol (85% DPPC 15% Cholesterol) lipid bilayer and its interactions with different drug molecules. For this purpose, I am using LIPID14 force field and GAFF force field.
According to the literature data, phase transition temperature is still higher than the value used in the experiments.
I would like to know if it is still possible to simulate this system. Indeed, although in the various tutorials the target temperature in the simulation was much higher than phase transition temperature, I found other examples where the situation was the opposite, like here:

http://pubs.rsc.org/en/Content/ArticleLanding/2015/CP/c5cp01937k#!divAbstracthttp://pubs.rsc.org/en/Content/ArticleLanding/2015/CP/c5cp01937k#!divAbstract

Can you suggest me a proper simulation protocol and/or more literature references?
I thank you in advance for your help and collaboration.
With my best regards,

Tommaso Casalini
Post-doctoral fellow, ETH Zurich
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Received on Mon Jan 23 2017 - 15:00:02 PST
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