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Parameters for Unsaturated Phospholipids

Rick Venable rvenable at deimos.cber.nih.gov
Mon Jun 24 19:06:12 EST 1996

On Mon, 17 Jun 1996 20:51:40 -0500 Chris Sheldahl asked:
> Does anyone know of any parameter files for phospholipids with unsaturated
> hydrocarbon chains? 

> I'm interested in modeling POPC bilayers but the only phospholipids listed
> in the CHARMM22 topology have only saturated hydrocarbon chains. From
> this, I'm *assuming* that parameters for the unsaturated fatty acid
> carbons aren't in the CHARMM22 lipid parameter set. 

Aliphatic double bond parameters have recently been added to the lipid parameter
set distributed with the academic version of CHARMM; they are available in the
latest release, c24b2, as distributed from Harvard.  We are testing them in our
lab via simulations based on the DOPC diffraction data of Stephen White.

They may also be available from the developer, Prof. Alex MacKerell, of
the Univ. of MD at Baltimore (UMAB) School of Pharmacy.

I believe these have been developed with more rigor than those in the 
references cited earlier in this thread (H. Heller, et. al.; T. Schlick, 
et. al.), and would recommend seeking these before any of the others.

Rick Venable                  =====\     |=|    "Eschew Obfuscation"
FDA/CBER Biophysics Lab       |____/     |=|
Bethesda, MD  U.S.A.          |   \  /   |=|  / Not an official statement \
rvenable at deimos.cber.nih.gov       \/    |=|  \  or position of the FDA.  /

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