[gmx-users] water models

[Justin Lemkul]

On 3/3/16 5:27 PM, Irem Altan wrote:
>
>> On Mar 3, 2016, at 5:06 PM, Justin Lemkul <jalemkul at vt.edu> wrote:
>>
>>
>>
>> On 3/3/16 2:21 PM, Irem Altan wrote:
>>> Hi,
>>>
>>> I have two general questions about TIP5P and GROMACS version 5.1.2. (I am
>>> using AMBER99SB).
>>>
>>> - Is it normal that TIP5P does not work out of the box? When I do pdb2gmx
>>> without modifying force field files, I get an error saying Residue 'HO5' not
>>> found in residue topology database . This is really confusing, as there
>>> exists a tip5p.gro, tip5p.itp, the LJ parameters exists within
>>> ffnonbonded.itp, the atoms are defined in atomtypes.atp, but there is nothing
>>> within aminoacids.rtp and aminoacids.hdb. Is it meant to be that way?
>>>
>>
>> Normally the water topology is simply taken care of by #including the appropriate stock topology.  pdb2gmx will try to create bonds between the atoms, which is not normal for rigid water models.
>
> So am I incorrect in creating relevant entries in aminoacids.rtp and aminoacids.hdb?
>

It certainly won't give you a rigid water model.  Process the protein with 
pdb2gmx, solvate with the available tip5p.gro and use tip5p.itp to describe the 
waters.

-Justin

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

Justin A. Lemkul, Ph.D.
Ruth L. Kirschstein NRSA Postdoctoral Fellow

Department of Pharmaceutical Sciences
School of Pharmacy
Health Sciences Facility II, Room 629
University of Maryland, Baltimore
20 Penn St.
Baltimore, MD 21201

jalemkul at outerbanks.umaryland.edu | (410) 706-7441
http://mackerell.umaryland.edu/~jalemkul

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