[gmx-users] Quick question: is TIP3P water model available in GROMOS54a7 force field?

[Justin Lemkul]

On 4/27/20 7:43 PM, shakira shukoor wrote:
> Hi
> As far as I know tip3p water model is modelled to use in combination with
> CHARMM force field. However there is nothing wrong in using TIP3P in
> combination with GROMOS force field. And u will have both the bonded and
> non bonded parameters of that specific water model in tip3p,itp file
> itself. You don't have to get it from the force field. Instead you have to
> add this itp file to the defined topology file you are giving.

GROMOS force fields were parametrized for use with SPC. As far as I 
know, no one has demonstrated that the use of TIP3P with GROMOS is valid.

-Justin

> On Tue, Apr 28, 2020 at 4:29 AM Wei-Tse Hsu <Weitse.Hsu at colorado.edu> wrote:
>
>> Dear gmx users,
>> I prepared a topology using Open Forcefiled for my system. To make GROMACS
>> able to recognize the water molecules and the ions to be added, I need to
>> include itp files (such as tip3p.itp, spc.itp, ions.itp, etc.) in my
>> topology file (.top file). I was planning to use GROMOS54a7 with TIP3P
>> water model, so I add the following lines to my topology file:
>>
>> ; Include water topology
>> #include "gromos54a7.ff/tip3p.itp"
>>
>> In gromos54a7.ff, there is indeed a tip3p.itp file. However, getting the
>> error of " Atomtype OWT3 not found", I later found that OWT3 was not
>> defined in ffnonbonded.itp. I also tried pdb2gmx command using other system
>> and chose gromos54a7 force field, but there is no option for selecting
>> TIP3P water model. Therefore, I wonder if TIP3P water model is actually not
>> available in GROMOS54a7 force field even if there is a tip3p.itp in
>> gromos54a7.ff. I might just use SPC water model instead, but I want to make
>> sure that my understanding is correct. Thank you!
>>
>> Best,
>> Wei-Tse
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>

-- 
==================================================

Justin A. Lemkul, Ph.D.
Assistant Professor
Office: 301 Fralin Hall
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Virginia Tech Department of Biochemistry
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