[gmx-users] how to simulate crystals in Gromacs

Tsjerk Wassenaar tsjerkw at gmail.com
Thu Apr 7 10:54:31 CEST 2011


Hi,

When building crystals, you first have to generate all symmetry mates
for a single unit cell. This may involve both rotations and
translations, and the information should be present in the structure
file. The unit cell can then be used to build a larger crystal with
genconf. With Pymol you can build symmetry mates from a structure
file, and on the pymolwiki there's a script to build a unit cell for a
given structure.
Mind first to convert the structure into the proper format for the
force field description you're using, as it will be more convenient to
build the topology for the crystal afterwards.

Hope it helps,

Tsjerk

2011/4/7 Mark Abraham <Mark.Abraham at anu.edu.au>:
> On 7/04/2011 4:21 PM, ZHANG Lu wrote:
>> Thank you for your answer.
>> Could you give me some advice on the size of cell box? What is the proper
>> size if I want to do MD simulation in crystal environment?
>> I didn't change the cell size when I convert cif file to pdb file; in
>> other word, I didn't use editconf to produce the cell box. What I did was
>> just :
>> pdb2gmx -> genconf ( -nbox 10 10 10 -dist 0.5 0.5 0.5 ) -> genbox. Was it
>> wrong?
>
> I don't know. When you opened it in a visualization program and saw the
> periodic box, and turned on the "show periodic images" option, did it
> look reasonable?
>
> Mark
>
>> Below is the coordination and cell box after I run pdb2gmx. I use water to
>> fill in the box after genconf.
>>
>>     1CLC    OBD    1  -0.042   0.476   0.219
>>     1CLC    O1D    2  -0.298   0.731   0.310
>>     1CLC    O2D    3  -0.163   0.650   0.469
>>     1CLC    O1A    4  -0.697   0.691   0.093
>>     1CLC    O2A    5  -0.822   0.826   0.214
>>     1CLC    CMB    6  -0.877   0.164   0.937
>>     1CLC    CAB    7  -0.708  -0.089   1.050
>>     1CLC    CBB    8  -0.820  -0.108   1.104
>>     1CLC    CMC    9  -0.224  -0.302   0.948
>>     1CLC    CAC   10   0.016  -0.236   0.743
>>     1CLC    CBC   11   0.014  -0.333   0.627
>>     1CLC    CMD   12   0.106   0.164   0.377
>>     1CLC    CAD   13  -0.122   0.426   0.298
>>     1CLC    CBD   14  -0.260   0.494   0.322
>>     1CLC    CAA   15  -0.598   0.558   0.332
>>     1CLC    CBA   16  -0.685   0.684   0.330
>>     1CLC    CMA   17  -0.672   0.604   0.686
>>     1CLC    CGD   18  -0.246   0.640   0.366
>>     1CLC    CED   19  -0.149   0.789   0.509
>>     1CLC    CGA   20  -0.733   0.732   0.198
>>     1CLC     C1   21  -0.878   0.885   0.095
>>     1CLC    CMG   22  -0.373   0.175   0.683
>>     1CLC     NB   23  -0.540   0.110   0.783
>>     1CLC     NC   24  -0.278  -0.005   0.729
>>     1CLC     ND   25  -0.234   0.194   0.534
>>     1CLC     NA   26  -0.492   0.328   0.583
>>     1CLC    C1B   27  -0.657   0.181   0.798
>>     1CLC    C2B   28  -0.741   0.114   0.897
>>     1CLC    C3B   29  -0.670   0.008   0.944
>>     1CLC    C4B   30  -0.543   0.006   0.871
>>     1CLC    CHC   31  -0.442  -0.086   0.890
>>     1CLC    C1C   32  -0.317  -0.091   0.824
>>     1CLC    C2C   33  -0.214  -0.193   0.847
>>     1CLC    C3C   34  -0.112  -0.163   0.760
>>     1CLC    C4C   35  -0.154  -0.045   0.688
>>     1CLC    CHD   36  -0.078   0.019   0.591
>>     1CLC    C1D   37  -0.112   0.131   0.520
>>     1CLC    C2D   38  -0.033   0.201   0.421
>>     1CLC    C3D   39  -0.115   0.309   0.380
>>     1CLC    C4D   40  -0.234   0.301   0.455
>>     1CLC    CHA   41  -0.325   0.405   0.430
>>     1CLC    C1A   42  -0.448   0.417   0.491
>>     1CLC    C2A   43  -0.545   0.533   0.476
>>     1CLC    C3A   44  -0.657   0.499   0.577
>>     1CLC    C4A   45  -0.612   0.366   0.634
>>     1CLC    CHB   46  -0.687   0.294   0.727
>>     1CLC   HMB1   47  -0.919   0.099   1.010
>>     1CLC   HMB2   48  -0.868   0.263   0.978
>>     1CLC   HMB3   49  -0.941   0.167   0.851
>>     1CLC    HAB   50  -0.629  -0.151   1.086
>>     1CLC   HBB1   51  -0.831  -0.182   1.180
>>     1CLC   HBB2   52  -0.905  -0.049   1.074
>>     1CLC   HMC1   53  -0.317  -0.294   1.000
>>     1CLC   HMC2   54  -0.143  -0.294   1.018
>>     1CLC   HMC3   55  -0.219  -0.397   0.899
>>     1CLC   HAC1   56   0.029  -0.295   0.831
>>     1CLC   HAC2   57   0.089  -0.162   0.718
>>     1CLC   HBC1   58   0.108  -0.382   0.619
>>     1CLC   HBC2   59  -0.063  -0.406   0.643
>>     1CLC   HBC3   60  -0.006  -0.280   0.536
>>     1CLC   HMD1   61   0.139   0.078   0.430
>>     1CLC   HMD2   62   0.172   0.246   0.397
>>     1CLC   HMD3   63   0.106   0.144   0.272
>>     1CLC    HBD   64  -0.320   0.500   0.234
>>     1CLC   HAA1   65  -0.661   0.476   0.307
>>     1CLC   HAA2   66  -0.512   0.580   0.271
>>     1CLC   HBA1   67  -0.774   0.656   0.383
>>     1CLC   HBA2   68  -0.622   0.762   0.367
>>     1CLC   HMA1   69  -0.751   0.575   0.753
>>     1CLC   HMA2   70  -0.580   0.612   0.740
>>     1CLC   HMA3   71  -0.696   0.698   0.642
>>     1CLC   HED1   72  -0.082   0.795   0.592
>>     1CLC   HED2   73  -0.245   0.827   0.538
>>     1CLC   HED3   74  -0.111   0.846   0.427
>>     1CLC    H11   75  -0.949   0.960   0.123
>>     1CLC    H12   76  -0.927   0.809   0.037
>>     1CLC    H13   77  -0.799   0.929   0.037
>>     1CLC    HHC   78  -0.460  -0.161   0.963
>>     1CLC    HHD   79   0.018  -0.024   0.570
>>     1CLC    H2A   80  -0.497   0.626   0.495
>>     1CLC    H3A   81  -0.754   0.495   0.531
>>     1CLC    HHB   82  -0.785   0.334   0.746
>>    0.87600   2.58600   0.73936   0.00000   0.00000   0.00000   0.00000
>> -0.41322   0.00000
>>
>>
>> Could you suggest some possible reasons for the bad result of MD run?
>>
>> Thank you,
>> Lu
>>
>>
>>
>> ---------------------------- Original Message ----------------------------
>> Subject: Re: [gmx-users] how to simulate crystals in Gromacs
>> From:    "Mark Abraham" <Mark.Abraham at anu.edu.au>
>> Date:    Thu, April 7, 2011 12:05 pm
>> To:      "Discussion list for GROMACS users" <gmx-users at gromacs.org>
>> --------------------------------------------------------------------------
>>
>> On 7/04/2011 1:55 PM, ZHANG Lu wrote:
>>> Dear all,
>>>    I am now trying to simulate crystals in Gromacs.
>>>    What I did was to convert the original crystal structure in cif format
>>> to pdb format and then use genconf to replicate the cells and run MD.
>>>    Is it proper to do it in this way?
>> It's workable. Whether you need to replicate depends on the size of the
>> periodic cell. Whether your box had enough space around the "outer"
>> atoms is also a concern.
>>
>>>  Because the structure I got after MD
>>> run was completely a mess ( not like crystals any more).
>>>    Could anyone tell me the correct way to do MD simulation in crystal
>>> environment?
>> There are a large number of possible reasons of the problem. We simply
>> do not have enough information to suggest anything.
>>
>> Mark
>
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-- 
Tsjerk A. Wassenaar, Ph.D.

post-doctoral researcher
Molecular Dynamics Group
* Groningen Institute for Biomolecular Research and Biotechnology
* Zernike Institute for Advanced Materials
University of Groningen
The Netherlands



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