[gmx-users] Topology file of molecule

Magnus Lundborg magnus.lundborg at scilifelab.se
Thu Nov 23 13:51:51 CET 2017


Dear Krzysztof,

I wouldn't be too worried about the fact that GAFF parameters have been 
used for proper and improper torsion angles. It happens quite a lot with 
the OPLS-AA forcefield. But as always, it is good to verify that the 
topology behaves as expected. Unfortunately there is no objective way to 
do this. If there are no experimentally measured properties available of 
your molecule it is a bit risky to proceed. However, I would recommend 
running short simulations of the molecule in vacuum (NVT) and in a 
simulation box solvated by itself just to see that it does at least not 
behave very strangely. If it seems OK I think you can proceed with your 
studies, but as always with an eye open for strange behaviour.

I hope that helps you.

Best regards,

Magnus

On 2017-11-23 10:24, Krzysztof Kolman wrote:
> Dear Gromacs Users,
>
> I would like to perform a simulation of adsorption of 3,4-Dihydroxybenzoic
> acid (34DHBA) on silica surface using the OPLS-AA forcefield. I created
> topology files for the silica surface based on the information found in
> papers describing simulations of quartz (Wensink 2000
> - 10.1021/la053284f, van der Spoel 2006 -10.1021/la053284f ). The topology
> for 34DHBA was created using STaGE script (Lundborg 2015
> - 10.1021/jp505332p) but some of the parameters (dihedrals) were missing
> and GAFF parameters were used instead. Please find below the content of itp
> file:
>
> [ moleculetype ]
> ; Name            nrexcl
>   34DHBA_opls 3
>
> [ atoms ]
> ;   nr  type  resi  res  atom  cgnr     charge      mass       ; qtot
>   bond_type
>    1    opls_145 1   LIG   C1    1     -0.115000   12.01100     ; -0.115000
>   CA
>    2    opls_166 1   LIG   C2    2      0.150000   12.01100     ; 0.035000
>   CA
>    3    opls_166 1   LIG   C3    3      0.150000   12.01100     ; 0.185000
>   CA
>    4    opls_145 1   LIG   C4    4     -0.115000   12.01100     ; 0.070000
>   CA
>    5    opls_145 1   LIG   C5    5     -0.115000   12.01100     ; -0.045000
>   CA
>    6    opls_145 1   LIG   C6    6     -0.115000   12.01100     ; -0.160000
>   CA
>    7    opls_167 1   LIG   OC3   7     -0.585000   15.99940     ; -0.745000
>   OH
>    8    opls_167 1   LIG   OC2   8     -0.585000   15.99940     ; -1.330000
>   OH
>    9    opls_470 1   LIG   C9    9      0.635000   12.01100     ; -0.695000
>   C
>    10   opls_269 1   LIG   OC91  10    -0.440000   15.99940     ; -1.135000
>   O_3
>    11   opls_268 1   LIG   OC92  11    -0.530000   15.99940     ; -1.665000
>   OH
>    12   opls_146 1   LIG   HC1   12     0.115000    1.00800     ; -1.550000
>   HA
>    13   opls_146 1   LIG   HC4   13     0.115000    1.00800     ; -1.435000
>   HA
>    14   opls_146 1   LIG   HC6   14     0.115000    1.00800     ; -1.320000
>   HA
>    15   opls_168 1   LIG   HO3   15     0.435000    1.00800     ; -0.885000
>   HO
>    16   opls_168 1   LIG   HO2   16     0.435000    1.00800     ; -0.450000
>   HO
>    17   opls_270 1   LIG   HO92  17     0.450000    1.00800     ; 0.000000
>   HO
>
> [ bonds ]
> ;   ai     aj funct   r             k
>      1   2   1   1.4000e-01   3.9246e+05 ; CA - CA
>      1   6   1   1.4000e-01   3.9246e+05 ; CA - CA
>      1   12   1   1.0800e-01   3.0711e+05 ; CA - HA
>      2   3   1   1.4000e-01   3.9246e+05 ; CA - CA
>      2   8   1   1.3640e-01   3.7656e+05 ; CA - OH
>      3   4   1   1.4000e-01   3.9246e+05 ; CA - CA
>      3   7   1   1.3640e-01   3.7656e+05 ; CA - OH
>      4   5   1   1.4000e-01   3.9246e+05 ; CA - CA
>      4   13   1   1.0800e-01   3.0711e+05 ; CA - HA
>      5   6   1   1.4000e-01   3.9246e+05 ; CA - CA
>      5   9   1   1.4900e-01   3.3472e+05 ; CA - C
>      6   14   1   1.0800e-01   3.0711e+05 ; CA - HA
>      7   15   1   9.4500e-02   4.6275e+05 ; OH - HO
>      8   16   1   9.4500e-02   4.6275e+05 ; OH - HO
>      9   10   1   1.2290e-01   4.7698e+05 ; C - O_3
>      9   11   1   1.3640e-01   3.7656e+05 ; C - OH
>      11   17   1   9.4500e-02   4.6275e+05 ; OH - HO
>
> [ pairs ]
> ;   ai     aj    funct
>       1      4      1 ;     C1 - C4
>       1      7      1 ;     C1 - OC3
>       1      9      1 ;     C1 - C9
>       1     16      1 ;     C1 - HO2
>       2      5      1 ;     C2 - C5
>       2     13      1 ;     C2 - HC4
>       2     14      1 ;     C2 - HC6
>       2     15      1 ;     C2 - HO3
>       3      9      1 ;     C3 - C9
>       3     16      1 ;     C3 - HO2
>       4      8      1 ;     C4 - OC2
>       4     10      1 ;     C4 - OC91
>       4     11      1 ;     C4 - OC92
>       4     14      1 ;     C4 - HC6
>       4     15      1 ;     C4 - HO3
>       5      7      1 ;     C5 - OC3
>       5     17      1 ;     C5 - HO92
>       6      3      1 ;     C6 - C3
>       6      8      1 ;     C6 - OC2
>       6     10      1 ;     C6 - OC91
>       6     11      1 ;     C6 - OC92
>       6     13      1 ;     C6 - HC4
>       7      8      1 ;    OC3 - OC2
>       7     13      1 ;    OC3 - HC4
>       9     13      1 ;     C9 - HC4
>       9     14      1 ;     C9 - HC6
>      10     17      1 ;   OC91 - HO92
>      12      3      1 ;    HC1 - C3
>      12      5      1 ;    HC1 - C5
>      12      8      1 ;    HC1 - OC2
>      12     14      1 ;    HC1 - HC6
>
> [ angles ]
> ;   ai     aj     ak    funct   theta         cth
>      1   2   3   1   1.2000e+02   5.2718e+02 ; CA - CA - CA
>      1   2   8   1   1.2000e+02   5.8576e+02 ; CA - CA - OH
>      1   6   5   1   1.2000e+02   5.2718e+02 ; CA - CA - CA
>      1   6   14   1   1.2000e+02   2.9288e+02 ; CA - CA - HA
>      2   1   6   1   1.2000e+02   5.2718e+02 ; CA - CA - CA
>      2   1   12   1   1.2000e+02   2.9288e+02 ; CA - CA - HA
>      2   3   4   1   1.2000e+02   5.2718e+02 ; CA - CA - CA
>      2   3   7   1   1.2000e+02   5.8576e+02 ; CA - CA - OH
>      2   8   16   1   1.1300e+02   2.9288e+02 ; CA - OH - HO
>      3   2   8   1   1.2000e+02   5.8576e+02 ; CA - CA - OH
>      3   4   5   1   1.2000e+02   5.2718e+02 ; CA - CA - CA
>      3   4   13   1   1.2000e+02   2.9288e+02 ; CA - CA - HA
>      3   7   15   1   1.1300e+02   2.9288e+02 ; CA - OH - HO
>      4   3   7   1   1.2000e+02   5.8576e+02 ; CA - CA - OH
>      4   5   6   1   1.2000e+02   5.2718e+02 ; CA - CA - CA
>      4   5   9   1   1.2000e+02   7.1128e+02 ; CA - CA - C
>      5   4   13   1   1.2000e+02   2.9288e+02 ; CA - CA - HA
>      5   6   14   1   1.2000e+02   2.9288e+02 ; CA - CA - HA
>      5   9   10   1   1.2040e+02   6.6944e+02 ; CA - C - O_3
>      5   9   11   1   1.2000e+02   5.8576e+02 ; CA - C - OH
>      6   1   12   1   1.2000e+02   2.9288e+02 ; CA - CA - HA
>      6   5   9   1   1.2000e+02   7.1128e+02 ; CA - CA - C
>      9   11   17   1   1.1300e+02   2.9288e+02 ; C - OH - HO
>      10   9   11   1   1.2100e+02   6.6944e+02 ; O_3 - C - OH
>
> [ dihedrals ] ; propers
> ; for gromacs 4.5 or higher, using funct 9
> ;    i      j      k      l   func   phase     kd      pn
>       1      2      3      4      9   180.00  15.16700   2 ;     C1-    C2-
>    C3-    C4  !Warning using GAFF parameters!
>       1      2      3      7      9   180.00  15.16700   2 ;     C1-    C2-
>    C3-   OC3  !Warning using GAFF parameters!
>       1      2      8     16      9   180.00   3.76560   2 ;     C1-    C2-
>   OC2-   HO2  !Warning using GAFF parameters!
>       1      6      5      4      9   180.00  15.16700   2 ;     C1-    C6-
>    C5-    C4  !Warning using GAFF parameters!
>       1      6      5      9      9   180.00  15.16700   2 ;     C1-    C6-
>    C5-    C9  !Warning using GAFF parameters!
>       2      1      6      5      9   180.00  15.16700   2 ;     C2-    C1-
>    C6-    C5  !Warning using GAFF parameters!
>       2      1      6     14      9   180.00  15.16700   2 ;     C2-    C1-
>    C6-   HC6  !Warning using GAFF parameters!
>       2      3      4      5      9   180.00  15.16700   2 ;     C2-    C3-
>    C4-    C5  !Warning using GAFF parameters!
>       2      3      4     13      9   180.00  15.16700   2 ;     C2-    C3-
>    C4-   HC4  !Warning using GAFF parameters!
>       2      3      7     15      9   180.00   3.76560   2 ;     C2-    C3-
>   OC3-   HO3  !Warning using GAFF parameters!
>       3      2      8     16      9   180.00   3.76560   2 ;     C3-    C2-
>   OC2-   HO2  !Warning using GAFF parameters!
>       3      4      5      6      9   180.00  15.16700   2 ;     C3-    C4-
>    C5-    C6  !Warning using GAFF parameters!
>       3      4      5      9      9   180.00  15.16700   2 ;     C3-    C4-
>    C5-    C9  !Warning using GAFF parameters!
>       4      3      2      8      9   180.00  15.16700   2 ;     C4-    C3-
>    C2-   OC2  !Warning using GAFF parameters!
>       4      3      7     15      9   180.00   3.76560   2 ;     C4-    C3-
>   OC3-   HO3  !Warning using GAFF parameters!
>       4      5      6     14      9   180.00  15.16700   2 ;     C4-    C5-
>    C6-   HC6  !Warning using GAFF parameters!
>       4      5      9     10      9   180.00   4.18400   2 ;     C4-    C5-
>    C9-  OC91  !Warning using GAFF parameters!
>       4      5      9     11      9   180.00   4.18400   2 ;     C4-    C5-
>    C9-  OC92  !Warning using GAFF parameters!
>       5      4      3      7      9   180.00  15.16700   2 ;     C5-    C4-
>    C3-   OC3  !Warning using GAFF parameters!
>       5      9     11     17      9   180.00   9.62320   2 ;     C5-    C9-
> OC92-  HO92  !Warning using GAFF parameters!
>       6      1      2      3      9   180.00  15.16700   2 ;     C6-    C1-
>    C2-    C3  !Warning using GAFF parameters!
>       6      1      2      8      9   180.00  15.16700   2 ;     C6-    C1-
>    C2-   OC2  !Warning using GAFF parameters!
>       6      5      4     13      9   180.00  15.16700   2 ;     C6-    C5-
>    C4-   HC4  !Warning using GAFF parameters!
>       6      5      9     10      9   180.00   4.18400   2 ;     C6-    C5-
>    C9-  OC91  !Warning using GAFF parameters!
>       6      5      9     11      9   180.00   4.18400   2 ;     C6-    C5-
>    C9-  OC92  !Warning using GAFF parameters!
>       7      3      2      8      9   180.00  15.16700   2 ;    OC3-    C3-
>    C2-   OC2  !Warning using GAFF parameters!
>       7      3      4     13      9   180.00  15.16700   2 ;    OC3-    C3-
>    C4-   HC4  !Warning using GAFF parameters!
>       9      5      4     13      9   180.00  15.16700   2 ;     C9-    C5-
>    C4-   HC4  !Warning using GAFF parameters!
>       9      5      6     14      9   180.00  15.16700   2 ;     C9-    C5-
>    C6-   HC6  !Warning using GAFF parameters!
>      10      9     11     17      9     0.00   7.94960   1 ;   OC91-    C9-
> OC92-  HO92  !Warning using GAFF parameters!
>      10      9     11     17      9   180.00   9.62320   2 ;   OC91-    C9-
> OC92-  HO92  !Warning using GAFF parameters!
>      12      1      2      3      9   180.00  15.16700   2 ;    HC1-    C1-
>    C2-    C3  !Warning using GAFF parameters!
>      12      1      2      8      9   180.00  15.16700   2 ;    HC1-    C1-
>    C2-   OC2  !Warning using GAFF parameters!
>      12      1      6      5      9   180.00  15.16700   2 ;    HC1-    C1-
>    C6-    C5  !Warning using GAFF parameters!
>      12      1      6     14      9   180.00  15.16700   2 ;    HC1-    C1-
>    C6-   HC6  !Warning using GAFF parameters!
>
> [ dihedrals ] ; impropers
> ; treated as propers in GROMACS to use correct AMBER analytical function
> ;    i      j      k      l   func   phase     kd      pn
>       1      3      2      8      4   180.00   4.60240   2 ;     C1-    C3-
>    C2-   OC2  !Warning using GAFF parameters!
>       1      5      6     14      4   180.00   4.60240   2 ;     C1-    C5-
>    C6-   HC6  !Warning using GAFF parameters!
>       2      4      3      7      4   180.00   4.60240   2 ;     C2-    C4-
>    C3-   OC3  !Warning using GAFF parameters!
>       3      5      4     13      4   180.00   4.60240   2 ;     C3-    C5-
>    C4-   HC4  !Warning using GAFF parameters!
>       5     10      9     11      4   180.00  43.93200   2 ;     C5-  OC91-
>    C9-  OC92  !Warning using GAFF parameters!
>       9      4      5      6      4   180.00   4.60240   2 ;     C9-    C4-
>    C5-    C6  !Warning using GAFF parameters!
>      12      1      6      2      4   180.00   4.60240   2 ;    HC1-    C1-
>    C6-    C2  !Warning using GAFF parameters!
>
> Generally one should not mix different forcefiedls but my question is how
> big "mistake" I make running a simulation using the parameters shown above.
> Is there any benchmark that allows to evaluate the quality of a topology
> file (maybe by calculating some experimental properties)?
>
> Thank you in advance for your help.
>
> Best regards,
> Krzysztof




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