[gmx-users] -rtpo option for pdb2gmx

[Justin Lemkul]

On 3/24/18 12:19 AM, Robert König wrote:
> Hello,
> I try to use a modified OPLSAA forcefield with GROMACS 2018 and I get this error:
>
> -------------------------------------------------------
> Program:     gmx pdb2gmx, version 2018
> Source file: src/gromacs/gmxpreprocess/resall.cpp (line 535)
>
> Fatal error:
> Found rtp entries for 'ACE' in both 'aminoacids' and
> './oplsaa.ff/ffoplsgas.rtp'. If you want the first definition to override the
> second one, set the -rtpo option of pdb2gmx.
>
> For more information and tips for troubleshooting, please check the GROMACS
> website at http://www.gromacs.org/Documentation/Errors
> -------------------------------------------------------
>
> What is the -rtpo option of pdb2gmx and how can I use it? I didnt find documentation or discussion for that, where can I get it?

I don't think that's an actual option, so that error message needs to be 
corrected.

OPLS has "ACE" as an acetyl cap, so either pick a new name for your 
residue or generate a separate force field rather than trying to hack 
the existing one.

-Justin

-- 
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Justin A. Lemkul, Ph.D.
Assistant Professor
Virginia Tech Department of Biochemistry

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