How to add GAFF force field to gromcs?

GROMACS version: 2022
GROMACS modification: No
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Hello,

I’m new to gromacs and I’m trying to try a model for a drug molecule and some polymers. General AMBER force field might be a good option for me, but I have to add this force field to gromacs. I found this link on AMBER website, but it is very confusing to me:

https://ambermd.org/parmed_gromacs.html

Using Amber force fields in GROMACS and CHARMM

Jason Swails’ parmed program can make this an easy task. The first thing you need to do is create your prmtop and inpcrd files using tleap. After that, run amber.python with the following code:

import parmed as pmd
parm = pmd.load_file(‘name-of-your.prmtop’, ‘name-of-your.inpcrd’)
parm.save(‘gromacs.top’, format=‘gromacs’)
parm.save(‘gromacs.gro’)

Similar ideas work for CHARMM:

import parmed as pmd
parm = pmd.load_file(‘name-of-your.prmtop’, ‘name-of-your.inpcrd’)
parm.save(‘charmm.psf’)
parm.save(‘charmm.crd’)

For more information, visit the ParmEd github page.

Could anyone please help with this? Thank you!

Effy

Hello effy,

(1) The force field can be generated by this procedure, “https://ambermd.org/tutorials/advanced/tutorial27/pet.htm”. Please check and try.

(2) The **.prmtop and **.inpcrd files can be converted to **.top and **.gro file using acepype.py (mmtools/acpype.py at master · choderalab/mmtools · GitHub).

Regards
Ranajit

Thanks for considering ACPYPE, but please use the latest version here:

Thank you very much for your suggestions! They are very helpful and I’ll try them out.