[gmx-users] how to convert CGenFF into .itp file?

Albert mailmd2011 at gmail.com
Wed Dec 26 13:00:24 CET 2012

On 12/26/2012 12:39 PM, Peter C. Lai wrote:
> It should come with two files. A .prm file, which contains the actual
> forcefield parameters that you use the script to convert to bonded and
> nonbonded .itp and atomtypes.atp The .rtf file is the charmm equivalent of
> our .rtp file: it contains some premade residue topologies with charge and
> connectivity information. I don't know if there are scripts to convert this or
> not, but it's easy enough to get what you need by hand especially since if
> your ligand isn't in there, you'll have to create the .rtp entry on your own
> or get them from paramchem anyway...

THX for comments. It works now and I get a folder called cgenff-2b7.ff 
like what we seen in the share/top folder for other FF.

that's too complicated to real use. Initially,  I thought that the 
output for the ligand should be a single .itp file like what we found in 

Probably one can consider improve this script. As far as I know the 
CGenFF website can export full parameters for the ligand even it is 
already exist in CGenFF off line files. In this cases, the output file 
fro CGenFF website is independent from the offline FF and it already has 
complete necessary information for paramters and topology). Probably one 
can consider improve this script and export the output file as a single 
.itp file.


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