Re: Convert solvated CHARMM PDB + PSF to Amber

From: Michael Robinson (
Date: Wed Sep 16 2020 - 23:08:52 CDT

Hello Gianluca,

The ParmEd program is designed for conversion between force fields,
including CHARMM and Amber. It may be helpful for your work:

However, it is also possible to directly use the Amber FF in NAMD, without
having to convert anything. If you're simply trying to have your system
entirely using Amber parameters, it might be easier to do it in this way:

If you're trying to mix-and-match, using some Amber parameters and some
CHARMM parameters, that is likely to give unphysical results, and it's
generally advised to avoid this method.

Hopefully that's helpful,
Michael Robinson

On Wed, 16 Sep 2020 at 11:40, Gianluca Interlandi <>

> Dear all,
> Does anybody have any recommendation how to convert a solvated system
> (protein + solvent + ions) PDB + PSF from the CHARMM to the Amber force
> field so that it can be used in NAMD with the Abmer force field
> parameters?
> Thanks,
> Gianluca
> -----------------------------------------------------
> Gianluca Interlandi, PhD
> +1 (206) 685 4435
> Research Assistant Professor at the Department of Bioengineering
> at the University of Washington, Seattle WA U.S.A.
> -----------------------------------------------------

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