[gmx-users] pdb2gmx breaking bonds

Justin Lemkul jalemkul at vt.edu
Thu Aug 29 13:59:06 CEST 2013



On 8/29/13 5:38 AM, Ewa Brylska wrote:
> Hello everyone,
> I am trying to perform a simulation of CAL-B substrate.
> I added parameters of the substrate as instructed here:
> http://www.gromacs.org/Documentation/How-tos/Adding_a_Residue_to_a_Force_Field
> When I run pdb2gmx in obtained .gro file, 3 bonds (P-B, P-CT and P-CA)
> break. The only bond with P that stays intact is with OS. I visualised PDB
> and gro files in VMD, when loading gro file, it says there are 4 fragments
> of the molecule loaded.
> Command used: pdb2gmx -f sub.pdb -o sub.gro -p sub.top. It ends with
> information about the topology being written successfully.
> How can I resolve this issue and keep the substrate in one piece?
>

First and foremost, please consider the following:

http://www.gromacs.org/Downloads/Related_Software/Visualization_Software#Topology_bonds_vs_Rendered_bonds

What VMD thinks about the bonded structure is completely irrelevant to Gromacs. 
  Look in the text of the topology - are the bonds there?  pdb2gmx will do 
exactly what you tell it.

-Justin

> Greetings,
> Ewa
> ____
>
> PDB file goes as follows:
>
> HETATM    1  P1  PB1 A 318      -3.840  -9.371
> 7.084                       P
> HETATM    2  B   PB1 A 318      -5.264  -8.247
> 7.685                       B
> HETATM    3  OS1 PB1 A 318      -3.548  -9.380
> 5.490                       O
> HETATM    4  CT3 PB1 A 318      -3.954  -8.381
> 4.607                       C
> HETATM    5  CT4 PB1 A 318      -2.929  -8.335
> 3.485                       C
> HETATM    6  CT2 PB1 A 318      -5.314  -8.789
> 4.074                       C
> HETATM    7  CA1 PB1 A 318      -3.951 -11.129
> 7.544                       C
> HETATM    8  CA6 PB1 A 318      -3.323 -11.623
> 8.705                       C
> HETATM    9  CA5 PB1 A 318      -3.410 -12.987
> 9.041                       C
> HETATM   10  CA4 PB1 A 318      -4.132 -13.870
> 8.220                       C
> HETATM   11  CA3 PB1 A 318      -4.769 -13.388
> 7.065                       C
> HETATM   12  CA2 PB1 A 318      -4.678 -12.025
> 6.733                       C
> HETATM   13  CT5 PB1 A 318      -2.152  -8.739
> 7.577                       C
> HETATM   14  OS2 PB1 A 318      -1.867  -7.580
> 6.802                       O
> HETATM   15  C   PB1 A 318      -0.737  -6.824
> 6.943                       C
> HETATM   16  O2  PB1 A 318      -0.688  -5.748
> 6.353                       O
> HETATM   17  CT1 PB1 A 318       0.408  -7.314
> 7.805                       C
> HETATM   18  HB1 PB1 A 318      -4.815  -7.367
> 8.380                       H
> HETATM   19  HB2 PB1 A 318      -5.834  -7.750
> 6.739                       H
> HETATM   20  HB3 PB1 A 318      -6.048  -8.904
> 8.334                       H
> HETATM   21  H13 PB1 A 318      -4.001  -7.410
> 5.101                       H
> HETATM   22  HC9 PB1 A 318      -1.930  -8.277
> 3.914                       H
> HETATM   23  HC8 PB1 A 318      -3.013  -9.235
> 2.881                       H
> HETATM   24  HC7 PB1 A 318      -3.097  -7.454
> 2.871                       H
> HETATM   25  HC6 PB1 A 318      -5.307  -9.845
> 3.821                       H
> HETATM   26  HC5 PB1 A 318      -5.519  -8.209
> 3.186                       H
> HETATM   27  HC4 PB1 A 318      -6.083  -8.605
> 4.822                       H
> HETATM   28  HA1 PB1 A 318      -2.759 -10.961
> 9.346                       H
> HETATM   29  HA2 PB1 A 318      -2.914 -13.358
> 9.926                       H
> HETATM   30  HA3 PB1 A 318      -4.193 -14.919
> 8.472                       H
> HETATM   31  HA4 PB1 A 318      -5.325 -14.064
> 6.430                       H
> HETATM   32  HA5 PB1 A 318      -5.166 -11.661
> 5.840                       H
> HETATM   33  H12 PB1 A 318      -1.404  -9.510
> 7.398                       H
> HETATM   34  H11 PB1 A 318      -2.145  -8.482
> 8.634                       H
> HETATM   35  HC2 PB1 A 318       1.253  -6.646
> 7.661                       H
>
> And the gro file:
>
> HETATM    1  P1  PB1 A 318      -3.840  -9.371
> 7.084                       P
> HETATM    2  B   PB1 A 318      -5.264  -8.247
> 7.685                       B
> HETATM    3  OS1 PB1 A 318      -3.548  -9.380
> 5.490                       O
> HETATM    4  CT3 PB1 A 318      -3.954  -8.381
> 4.607                       C
> HETATM    5  CT4 PB1 A 318      -2.929  -8.335
> 3.485                       C
> HETATM    6  CT2 PB1 A 318      -5.314  -8.789
> 4.074                       C
> HETATM    7  CA1 PB1 A 318      -3.951 -11.129
> 7.544                       C
> HETATM    8  CA6 PB1 A 318      -3.323 -11.623
> 8.705                       C
> HETATM    9  CA5 PB1 A 318      -3.410 -12.987
> 9.041                       C
> HETATM   10  CA4 PB1 A 318      -4.132 -13.870
> 8.220                       C
> HETATM   11  CA3 PB1 A 318      -4.769 -13.388
> 7.065                       C
> HETATM   12  CA2 PB1 A 318      -4.678 -12.025
> 6.733                       C
> HETATM   13  CT5 PB1 A 318      -2.152  -8.739
> 7.577                       C
> HETATM   14  OS2 PB1 A 318      -1.867  -7.580
> 6.802                       O
> HETATM   15  C   PB1 A 318      -0.737  -6.824
> 6.943                       C
> HETATM   16  O2  PB1 A 318      -0.688  -5.748
> 6.353                       O
> HETATM   17  CT1 PB1 A 318       0.408  -7.314
> 7.805                       C
> HETATM   18  HB1 PB1 A 318      -4.815  -7.367
> 8.380                       H
> HETATM   19  HB2 PB1 A 318      -5.834  -7.750
> 6.739                       H
> HETATM   20  HB3 PB1 A 318      -6.048  -8.904
> 8.334                       H
> HETATM   21  H13 PB1 A 318      -4.001  -7.410
> 5.101                       H
> HETATM   22  HC9 PB1 A 318      -1.930  -8.277
> 3.914                       H
> HETATM   23  HC8 PB1 A 318      -3.013  -9.235
> 2.881                       H
> HETATM   24  HC7 PB1 A 318      -3.097  -7.454
> 2.871                       H
> HETATM   25  HC6 PB1 A 318      -5.307  -9.845
> 3.821                       H
> HETATM   26  HC5 PB1 A 318      -5.519  -8.209
> 3.186                       H
> HETATM   27  HC4 PB1 A 318      -6.083  -8.605
> 4.822                       H
> HETATM   28  HA1 PB1 A 318      -2.759 -10.961
> 9.346                       H
> HETATM   29  HA2 PB1 A 318      -2.914 -13.358
> 9.926                       H
> HETATM   30  HA3 PB1 A 318      -4.193 -14.919
> 8.472                       H
> HETATM   31  HA4 PB1 A 318      -5.325 -14.064
> 6.430                       H
> HETATM   32  HA5 PB1 A 318      -5.166 -11.661
> 5.840                       H
> HETATM   33  H12 PB1 A 318      -1.404  -9.510
> 7.398                       H
> HETATM   34  H11 PB1 A 318      -2.145  -8.482
> 8.634                       H
> HETATM   35  HC2 PB1 A 318       1.253  -6.646
> 7.661                       H
>

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

Justin A. Lemkul, Ph.D.
Postdoctoral Fellow

Department of Pharmaceutical Sciences
School of Pharmacy
Health Sciences Facility II, Room 601
University of Maryland, Baltimore
20 Penn St.
Baltimore, MD 21201

jalemkul at outerbanks.umaryland.edu | (410) 706-7441

==================================================



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