[gmx-users] Charge groups in Charmm for lipids

Thomas Piggot t.piggot at soton.ac.uk
Sat Aug 6 11:52:16 CEST 2011

The new GROMACS 4.5.4 version of the CHARMM36 force field files are now 
uploaded on the GROMACS website contributions section.

Just to note that if anyone downloaded the 4.5.4 version uploaded a few 
hours ago then the atomtypes.atp file was incomplete and should download 
this new version. Sorry for any problems caused by this.



On 06/08/11 02:28, Thomas Piggot wrote:
> Sure, I will upload a GROMACS 4.5.4 version of the force field files to
> the website.
> Cheers
> Tom
> On 06/08/11 01:34, Peter C. Lai wrote:
>> On 2011-08-05 06:48:09PM -0500, Thomas Piggot wrote:
>>> Hi,
>>> Yes, this was done on purpose to reflect the different use of charge groups in CHARMM and GROMACS. Check out the mailing list archives for more details about this.
>>> On another note you might like to take a look at the contributed CHARMM36 force field (available to download on the GROMACS website). There is a DPPG entry in the lipids.rtp file that should help in making a CHARMM27 DPPG rtp entry (if you wish to use the CHARMM27 lipids rather than the CHARMM36 ones).
>> Just as an aside, can you update your C36 with the C27 files for proteins and
>> nucleic acids? That saves us from having to copy the charmm27.ff files
>> for those compounds into charmm36.ff...(since the amino and nucleic acid
>> topologies in charmm36.ff still use nondistinct chargegroups requiring
>> the use of -nochargegrp to pdb2gmx)
>> Thanks

Dr Thomas Piggot
University of Southampton, UK.

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