[gmx-users] Fatal error: No atoms found in .rtp file in residue pairs
shima_arasteh2001 at yahoo.com
Sun May 13 19:06:41 CEST 2012
Even in gromos87, if I want to make a .rtp file for formyl, I need to put H atom in it? I mean, defining all atoms of a residue is necessary? Aren't the hydrogen atoms set by the gromacs package?
From: Justin A. Lemkul <jalemkul at vt.edu>
To: Discussion list for GROMACS users <gmx-users at gromacs.org>
Sent: Sunday, May 13, 2012 8:36 PM
Subject: Re: [gmx-users] Fatal error: No atoms found in .rtp file in residue pairs
On 5/13/12 11:43 AM, Shima Arasteh wrote:
> Again thanks for all your replies.
> As I got through your advices, I found that the atoms contribute in making bonds
> and angles in a residue , or make dihedrals in a residue ( or with atoms in next
> ones) plus the charge of a the residue should be defined properly in .rtp files
> to define the new residue in aminoacid.rtp file of CHARMM36 force field.
> So I arranged this lines to define formyl in .rtp file. And I got the topology.
> But there are some questions for me here:
> 1. How can I be sure the formyl which I defined is correct? Is getting the
> topology is enough to be sure of the correct output?
It is incorrect. As I said before, a formyl group is an aldehyde and has an H
atom attached to C, e.g. -CH(=O). At present, you are defining a -C=O group
with an incomplete carbon valence.
> The .rtp file for formyl is as below:
> [ For ]
> [ atoms ]
> ; name type charge chargegroup
> C CTL1 0.5700 0
> O O -0.5700 0
> [angles ]
> ai aj ak
> O C +N
> [ bonds ]
> C O
> C +N
> [ dihedrals ]
> O C +N +CA
Aside from the missing atom (and resulting missing bonds, angles, and dihedral),
the format of this entry is OK.
> 2. There are lots of numbers in .itp file which I got through the swissparam.
> But I think the charge of atoms may be useful in this file and also I can just
> find the atoms contribute in bonds and angles and.... . Am I right? Or I may get
> some other useful information which I can get through the files of swissparam?
If the existing bonded parameters for each interaction type (in ffbonded.itp)
are sufficient for defining these interactions, then you can omit the content of
the .itp file you've been using in the .rtp entry and rely on the force field to
look up those values. There may be some interactions that are not in agreement
(or do not exist), in which case you need to either define these parameters in
the .rtp entry itself or in ffbonded.itp so that they will be detected by grompp
> Thanks in advance, and sorry for disturbing you friends.
> *From:* Justin A. Lemkul <jalemkul at vt.edu>
> *To:* Discussion list for GROMACS users <gmx-users at gromacs.org>
> *Sent:* Saturday, May 12, 2012 10:12 PM
> *Subject:* Re: [gmx-users] Fatal error: No atoms found in .rtp file in residue pairs
> On 5/12/12 1:37 PM, Justin A. Lemkul wrote:
> > On 5/12/12 1:32 PM, Shima Arasteh wrote:
> >> Dear gmx users,
> >> I want to simulate a peptide in water. The peptide has a formyl residue as the
> >> N-terminus. I got the parameters of it and then add it to the .rtp file of
> >> charmm36.ff as below:
> >> [ For ]
> >> [ atoms ]
> >> ; name type charge chargegroup
> >> C C 0.4500 0
> >> O O -0.5700 0
> >> [ bonds ]
> >> ; ai aj fu b0 kb, b0 kb
> >> 1 2 1 0.12220 779866.6 0.12220 779866.6
> >> [ pairs ]
> >> ; ai aj fu
> >> [ angles ]
> >> ; ai aj ak fu th0 kth ub0 kub th0 kth ub0 kub
> >> 2 1 3 1 123.4390 403.48 123.4390 403.48
> >> 2 1 4 1 123.4390 403.48 123.4390 403.48
> >> [ dihedrals ]
> >> ; ai aj ak al fu phi0 kphi mult phi0 kphi mult
> >> But when I do what I described, I face this fatal error:
> >> Fatal error:
> >> No atoms found in .rtp file in residue pairs
> >> Would you help me with this problem? Did I add the formyl in a wrong way?
> > Your [pairs] directive is empty, hence the error. Your [dihedrals] directive
> > will also produce the same error. There are no possible pairs in a unit
> > containing so few atoms, so you don't even need this. You may need to define
> > dihedrals, however, but they also depend upon the next residue.
> > You also have several other mistakes:
> > 1. A formyl group has a proton on it; yours has none
> > 2. Your net charge on the formyl group is not zero, though this may or may not
> > be a consequence of point #1
> > 3. There is no connectivity information for linking to the next residue, which
> > will mean the formyl group will not be chemically bonded. This also affects your
> > dihedrals.
> Another that I just caught as I hit send:
> 4. In your [bonds] and [angles] directives, you use atom numbers - they should
> be names
> Justin A. Lemkul, Ph.D.
> Department of Biochemistry
> Virginia Tech
> Blacksburg, VA
> jalemkul[at]vt.edu <http://vt.edu> | (540) 231-9080
> gmx-users mailing list gmx-users at gromacs.org <mailto:gmx-users at gromacs.org>
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Justin A. Lemkul, Ph.D.
Department of Biochemistry
jalemkul[at]vt.edu | (540) 231-9080
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