[gmx-users] Charmm27 ff for membrane protein simulation

[Thomas Piggot]

By default in the CHARMM27 force field files there is no DPPC, as this 
is made up from a combination of other entries in the rtp file (because 
this is the way it is done in the CHARMM program's files). If you wish 
to use DPPC you can construct yourself a complete DPPC rtp entry. To do 
this you it is probably easiest to duplicate the DMPC entry and add the 
corresponding atoms and bonds for two extra carbons in each tail.

Alternatively you could use the CHARMM36 force field (available to 
download from the contributions section of the website), there should 
already be an entry for DPPC.

Cheers

Tom

On 18/10/11 19:45, Justin A. Lemkul wrote:
>
> James Starlight wrote:
>> Greetings!
>>
>>
>> Recently I've found that Charmm27 ff is widely used for the simulation
>> of the membrane proteins. I've tried to work with pure DPPC bilayer in
>> pdb2grx and obtain that charm27 ff included in the Gromacs is lack for
>> the parametries for the lipids.
>>
>> Could you tell me where I could obtain those parametries ( and tutorial
>> of how it might be included in processing of lipids) or full functional
>> charmm27 ff that already has pre-built those parametries?
>>
> Most of the common lipids are already present in lipids.rtp in charmm27.ff in
> Gromacs 4.5.x; if you are looking for lipids not present there, please be more
> specific as to what you need.
>
> The only membrane protein tutorial to my knowledge is my own.  Dealing with
> CHARMM should be significantly easier, however, as no modification of the force
> field is necessary.  Run pdb2gmx on a single lipid molecule, convert the .top to
> .itp (see the wiki) and #include it in the .top for your protein, just like in
> my tutorial.
>
> -Justin
>
>> Thank you for help
>>
>>
>> James
>>

-- 
Dr Thomas Piggot
University of Southampton, UK.