[gmx-users] Making itp files

Justin A. Lemkul jalemkul at vt.edu
Tue Sep 8 01:00:25 CEST 2009



mail-vtanchuk wrote:
> Dear GMX'ers,
>    Is there any reliable way of making an itp file for an arbitrary 
> structure? AFAIK there are two ways:
>         1) The Dundee PRODRG server. This is really a nice tool, but it 
> always gives the same protonation states. COOH always becomes COO- and 
> NH2 becomes NH3+.

You can control the protonation state.  See the PRODRG FAQ.

>         2) x2top. This utility hangs with my rather simple structure. 
> The structure is attached below. This is a file created by SwissPDB. It 
> contains hydrogens and connections. Nevertheless x2top ignores this 
> information and hanges (at least gives no result in 40 min).
>  

It depends on the version of x2top you're using, but if you use the -nopbc 
option with version 4.0.5, it doesn't hang.

Otherwise, there are a number of topology-generating tools on the User 
Contributions section of the Gromacs site.

-Justin

> So, the question is how to make an itp file with predefined protonation 
> (e.g. COOH and NH2 groups).
> 
> Here is a pdb file
>  
> COMPND    ?
> REMARK    File generated by Swiss-PdbViewer  3.70b15
> REMARK    http://www.expasy.org/spdbv/
> HETATM    1  C1  PDR     1      43.433  46.174  18.374  1.00  0.00
> HETATM    2  C2  PDR     1      42.232  46.505  18.873  1.00  0.00
> HETATM    3  C3  PDR     1      41.148  45.500  19.008  1.00  0.00
> HETATM    4  C4  PDR     1      41.322  44.220  18.637  1.00  0.00
> HETATM    5  C5  PDR     1      43.713  44.783  17.941  1.00  0.00
> HETATM    6  C6  PDR     1      42.617  43.776  18.072  1.00  0.00
> HETATM    7  C7  PDR     1      42.814  42.509  17.658  1.00  0.00
> HETATM    8  C8  PDR     1      44.112  42.120  17.056  1.00  0.00
> HETATM    9  C9  PDR     1      45.096  43.026  16.934  1.00  0.00
> HETATM   10  C10 PDR     1      44.906  44.416  17.421  1.00  0.00
> HETATM   11  O11 PDR     1      45.923  45.378  17.183  1.00  0.00
> HETATM   12  C12 PDR     1      46.990  45.244  18.162  1.00  0.00
> HETATM   13  C13 PDR     1      48.059  46.309  17.874  1.00  0.00
> HETATM   14  O14 PDR     1      47.658  47.553  18.487  1.00  0.00
> HETATM   15  C15 PDR     1      49.462  45.937  18.365  1.00  0.00
> HETATM   16  N16 PDR     1      50.433  46.887  17.760  1.00  0.00
> HETATM   17  C17 PDR     1      51.853  46.544  17.977  1.00  0.00
> HETATM   18  C18 PDR     1      52.609  47.864  18.047  1.00  0.00
> HETATM   19  C19 PDR     1      52.323  45.695  16.799  1.00  0.00
> HETATM   20  H20 PDR     1      44.210  46.934  18.283  1.00  0.00
> HETATM   21  H21 PDR     1      42.045  47.532  19.182  1.00  0.00
> HETATM   22  H22 PDR     1      40.189  45.815  19.415  1.00  0.00
> HETATM   23  H23 PDR     1      40.502  43.512  18.747  1.00  0.00
> HETATM   24  H24 PDR     1      42.022  41.768  17.745  1.00  0.00
> HETATM   25  H25 PDR     1      44.262  41.102  16.703  1.00  0.00
> HETATM   26  H26 PDR     1      46.043  42.752  16.477  1.00  0.00
> HETATM   27  H27 PDR     1      46.604  45.386  19.200  1.00  0.00
> HETATM   28  H28 PDR     1      47.445  44.230  18.086  1.00  0.00
> HETATM   29  H29 PDR     1      48.112  46.449  16.767  1.00  0.00
> HETATM   30  H30 PDR     1      46.667  47.789  18.307  1.00  0.00
> HETATM   31  H31 PDR     1      49.482  46.012  19.479  1.00  0.00
> HETATM   32  H32 PDR     1      49.703  44.893  18.063  1.00  0.00
> HETATM   33  H33 PDR     1      50.059  47.894  17.760  1.00  0.00
> HETATM   34  H34 PDR     1      52.006  45.989  18.938  1.00  0.00
> HETATM   35  H35 PDR     1      52.229  48.461  18.906  1.00  0.00
> HETATM   36  H36 PDR     1      53.699  47.688  18.188  1.00  0.00
> HETATM   37  H37 PDR     1      52.451  48.451  17.115  1.00  0.00
> HETATM   38  H38 PDR     1      51.808  44.708  16.822  1.00  0.00
> HETATM   39  H39 PDR     1      52.067  46.197  15.838  1.00  0.00
> HETATM   40  H40 PDR     1      53.421  45.523  16.846  1.00  0.00
> CONECT    1    2    5   20                  
> CONECT    2    3   21                       
> CONECT    3    4   22                       
> CONECT    4    6   23                       
> CONECT    5    6   10                       
> CONECT    6    7                            
> CONECT    7    8   24                       
> CONECT    8    9   25                       
> CONECT    9   10   26                       
> CONECT   10   11                            
> CONECT   11   12                            
> CONECT   12   13   27   28                  
> CONECT   13   14   15   29                  
> CONECT   14   30                            
> CONECT   15   16   31   32                  
> CONECT   16   17   33                       
> CONECT   17   18   19   34                  
> CONECT   18   35   36   37                  
> CONECT   19   38   39   40                  
> SPDBVT        1.0000000000         0.0000000000         0.0000000000
> SPDBVT        0.0000000000         1.0000000000         0.0000000000
> SPDBVT        0.0000000000         0.0000000000         1.0000000000
> SPDBVT        0.0000000000         0.0000000000         0.0000000000
> SPDBVT        0.0000000000         0.0000000000         0.0000000000
> SPDBVV default;
> SPDBVV     45.752312478050    1769.439927720726      20.000000000000
> SPDBVV        0.8492806468         0.0177824961         0.5276420811
> SPDBVV        0.4171748744         0.5899083148        -0.6913561342
> SPDBVV       -0.3235544887         0.8072744038         0.4935793046
> SPDBVV       46.9440002441        44.7815017700        17.6585006714
> SPDBVV        0.0000000000         0.0000000000         0.0000000000
> SPDBVf 23
> SPDBVl 1.00 1.00 1.00
> SPDBVb 0.00 0.00 0.00
> END
> I have also tried the same file without numbers in atom names and 
> without connections.
>  
> Any help will be hightly appreciated.
>  
> Sincerely yours,
> V. Tanchuk
> 
> 
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-- 
========================================

Justin A. Lemkul
Ph.D. Candidate
ICTAS Doctoral Scholar
Department of Biochemistry
Virginia Tech
Blacksburg, VA
jalemkul[at]vt.edu | (540) 231-9080
http://www.bevanlab.biochem.vt.edu/Pages/Personal/justin

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



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