[gmx-users] pdb2gmx assign CSER to non-terminal serine

Zheng Ruan zruan1991 at gmail.com
Tue May 3 18:09:02 CEST 2016


Thank you Justin!!! That's the problem. Now everything runs well.

Ruan

On Tue, May 3, 2016 at 12:04 PM, Justin Lemkul <jalemkul at vt.edu> wrote:

>
>
> On 5/3/16 12:02 PM, Zheng Ruan wrote:
>
>> Hi Gromacs Users,
>>
>> I'm using pdb2gmx to process my pdb files with a phospho-tyrosine
>> using amber99sb-ildn.ff. The relavant content in my pdb looks like this
>> (There is a serine before phosphorylated tyrosine):
>>
>> ATOM    202  N   SER    26      31.593 -68.669 -25.834  1.00208.96
>>   N
>> ATOM    203  CA  SER    26      32.638 -67.843 -25.302  1.00208.96
>>   C
>> ATOM    204  C   SER    26      31.995 -66.621 -24.727  1.00208.96
>>   C
>> ATOM    205  O   SER    26      30.979 -66.149 -25.232  1.00208.96
>>   O
>> ATOM    206  CB  SER    26      33.644 -67.365 -26.363  1.00208.96
>>   C
>> ATOM    207  OG  SER    26      34.330 -68.476 -26.921  1.00208.96
>>   O
>> ATOM    208  N   Y2P    27      32.567 -66.088 -23.628  1.00307.13
>>   N
>> ATOM    209  CA  Y2P    27      32.019 -64.903 -23.034  1.00307.13
>>   C
>> ATOM    210  C   Y2P    27      33.156 -64.013 -22.644  1.00307.13
>>   C
>> ATOM    211  O   Y2P    27      34.263 -64.481 -22.390  1.00307.13
>>   O
>> ATOM    212  CB  Y2P    27      31.197 -65.174 -21.762  1.00307.13
>>   C
>> ATOM    213  CG  Y2P    27      30.697 -63.861 -21.266  1.00307.13
>>   C
>> ATOM    214  OG  Y2P    27      29.295 -60.184 -19.874  1.00307.13
>>   O
>> ATOM    215  CD1 Y2P    27      29.578 -63.285 -21.820  1.00307.13
>>   C
>> ATOM    216  CD2 Y2P    27      31.346 -63.208 -20.242  1.00307.13
>>   C
>> ATOM    217  CE1 Y2P    27      29.115 -62.073 -21.365  1.00307.13
>>   C
>> ATOM    218  CE2 Y2P    27      30.887 -61.996 -19.783  1.00307.13
>>   C
>> ATOM    219  CZ  Y2P    27      29.768 -61.428 -20.343  1.00307.13
>>   C
>> ATOM    220  P   Y2P    27      29.208 -59.251 -20.980  0.00  0.00
>>   P
>> ATOM    221  O1P Y2P    27      30.631 -58.900 -21.344  0.00  0.00
>>   O
>> ATOM    222  O2P Y2P    27      28.565 -59.705 -22.398  0.00  0.00
>>   O
>> ATOM    223  O3P Y2P    27      28.289 -58.144 -20.524  0.00  0.00
>>   O
>>
>> I followed the online protocol to convert the amber parameters from Bryce
>> into my force field. The Y2P entry in aminoacids.rtp I add looks like
>> this:
>>
>> [ Y2P ]
>>  [ atoms ]
>>      N    N           -0.516300     1
>>      H    H            0.293600     2
>>     CA    CT           0.141279     3
>>     HA    H1           0.027982     4
>>     CB    CT          -0.251171     5
>>    HB1    HC           0.081930     6
>>    HB2    HC           0.081930     7
>>     CG    CA           0.073446     8
>>    CD1    CA          -0.198084     9
>>    HD1    HA           0.112503    10
>>    CE1    CA          -0.254266    11
>>    HE1    HA           0.161606    12
>>     CZ    C            0.477009    13
>>    CE2    CA          -0.254266    14
>>    HE2    HA           0.161606    15
>>    CD2    CA          -0.198084    16
>>    HD2    HA           0.112503    17
>>     OG    OS          -0.557944    18
>>      P    P            1.380672    19
>>    O1P    O2          -0.943550    20
>>    O2P    O2          -0.943550    21
>>    O3P    O2          -0.943550    22
>>      C    C            0.536600    23
>>      O    O           -0.581900    24
>>  [ bonds ]
>>      N     H
>>      N    CA
>>     CA    HA
>>     CA    CB
>>     CA     C
>>     CB   HB1
>>     CB   HB2
>>     CB    CG
>>     CG   CD1
>>     CG   CD2
>>    CD1   HD1
>>    CD1   CE1
>>    CE1   HE1
>>    CE1    CZ
>>     CZ    OG
>>     CZ   CE2
>>    CE2   HE2
>>    CE2   CD2
>>    CD2   HD2
>>     OG   P
>>      P   O1P
>>      P   O2P
>>      C     O
>>     -C     N
>>  [ impropers ]
>>     -C    CA     N     H
>>     CA    +N     C     O
>>     CG   CE2   CD2   HD2
>>     CZ   CD2   CE2   HE2
>>    CD1    CZ   CE1   HE1
>>     CG   CE1   CD1   HD1
>>    CD1   CD2    CG    CB
>>    CE1   CE2    CZ    OG
>>
>> I also modified the aminoacids.hdb and ffbonded.itp accordingly. I then
>> use
>> the following command to process the pdb file:
>>
>> # g_pdb2gmx -f file.pdb -o file.gro -ignh
>> ...
>> Changing rtp entry of residue 26 SER to 'CSER'
>> ...
>> Renaming atom 'O' in residue 26 SER to 'OC2'
>> ...
>>
>> The seine before Y2P is changed to CSER, which is the terminal version of
>> serine. This creates trouble for further steps to prepare my MD. Is this
>> because I have a mistake in defining Y2P entry? Can I force pdb2gmx not
>> chaning SER26 to CSER? I can provide additional information if needed.
>> Thank you!
>>
>>
>
> http://www.gromacs.org/Documentation/How-tos/Adding_a_Residue_to_a_Force_Field
>
> You forgot step 5.
>
> -Justin
>
> --
> ==================================================
>
> Justin A. Lemkul, Ph.D.
> Ruth L. Kirschstein NRSA Postdoctoral Fellow
>
> Department of Pharmaceutical Sciences
> School of Pharmacy
> Health Sciences Facility II, Room 629
> University of Maryland, Baltimore
> 20 Penn St.
> Baltimore, MD 21201
>
> jalemkul at outerbanks.umaryland.edu | (410) 706-7441
> http://mackerell.umaryland.edu/~jalemkul
>
> ==================================================
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