[gmx-users] add a group to an amino acid

Mark Abraham Mark.Abraham at anu.edu.au
Tue Nov 9 11:43:16 CET 2010


On 9/11/2010 9:09 PM, hengame fallah wrote:
> Dear Mark,
>
> I edited my pdb like this:
> ...
> ATOM     41  N   BOC     3      -1.862   5.210   5.333
> ATOM     42  H   BOC     3      -2.325   4.344   5.618
> ATOM     43  CA  BOC     3      -1.001   5.232   4.169
> ATOM     44  HA1 BOC     3      -0.540   6.235   4.026
> ATOM     45  HA2 BOC     3      -0.172   4.511   4.360
> ATOM     46  CB  BOC     3      -1.797   4.794   2.924
> ATOM     47  HB1 BOC     3      -2.244   3.809   3.204
> ATOM     48  CG1 BOC     3      -2.976   5.730   2.589
> ATOM     49  CD1 BOC     3      -1.231   3.466   0.845
> ATOM     50  HD1 BOC     3      -2.070   2.790   1.081
> ATOM     51  CD2 BOC     3       0.120   5.408   1.353
> ATOM     52  HD2 BOC     3       0.357   6.277   1.986
> ATOM     53  CE1 BOC     3      -0.471   3.236  -0.312
> ATOM     54  HE1 BOC     3      -0.717   2.381  -0.964
> ATOM     55  CE2 BOC     3       0.881   5.182   0.197
> ATOM     56  HE2 BOC     3       1.706   5.870  -0.054
> ATOM     57  CZ  BOC     3       0.591   4.093  -0.639
> ATOM     58  CG2 BOC     3      -0.935   4.544   1.698
> ATOM     59  HG1 BOC     3      -3.530   5.331   1.707
> ATOM     60  HG2 BOC     3      -3.708   5.729   3.431
> ATOM     61  C   BOC     3      -2.565   7.148   2.291
> ATOM     62  O   BOC     3      -2.716   8.035   3.131
> ATOM     63  Cl  BOC     3       1.525   3.816  -2.062
> END
>
> and my .rtp file for [ BOC ] is:
>
> [ BOC ]
> [ atoms ]
>      N    opls_238   -0.500     1
>      H    opls_241    0.300     1
>     CA    opls_224B  -0.005     1
>    HA1    opls_140    0.060     1
>    HA2    opls_140    0.060     1
>     CB    opls_149    0.140     2
>    HB1    opls_140    0.060     2
>    CG1    opls_145   -0.115     2
>    CD1    opls_145   -0.115     3
>    HD1    opls_146    0.115     3
>    CD2    opls_145   -0.115     4
>    HD2    opls_146    0.115     4
>    CE1    opls_145   -0.115     5
>    HE1    opls_146    0.115     5
>    CE2    opls_145   -0.115     6
>    HE2    opls_146    0.115     6
>     CZ    opls_145    0.885     7
>     Cl    opls_264   -1.000     7
>    CG2    opls_071   -0.005     8
>    HG1    opls_140    0.060     8
>    HG2    opls_140    0.060     8
>      C    opls_235    0.700     9
>      O    opls_236   -0.700     9
> [ bonds ]
>      N     H
>      N    CA
>     CA   HA1
>     CA   HA2
>     CA    CB
>     CB   HB1
>     CB   CG1
>     CB   CG2
>    CG1   CD1
>    CG1   CD2
>    CD1   HD1
>    CD1   CE1
>    CD2   HD2
>    CD2   CE2
>    CE1   HE1
>    CE1    CZ
>    CE2   HE2
>    CE2    CZ
>     CZ    Cl
>    CG2   HG1
>    CG2   HG2
>    CG2     C
>      C     O
>     -C     N
>
> and still i got that error!
>
> Fatal error:
> Atom HB11 not found in rtp database in residue BOC, it looks a bit 
> like HB1

a) This structure is phenylalanine with *two* backbone methylene 
spacers, not the one you said in a previous email
b) Your charge groups are wrong (e.g. number 2)
c) Your charges are doubtful (CG1 is negative???)
d) Your atom types are worth checking (should the two backbone methylene 
carbons have those types?)
e) The atom ordering of the coordinate file and .rtp file need to match
f) The atom coordinates do not correspond to the atom labels they are 
given - presumably you got another bunch of "long bond" warnings that 
you didn't include in your last email.

Mark

>
> On Tue, Nov 9, 2010 at 1:12 PM, Mark Abraham <Mark.Abraham at anu.edu.au 
> <mailto:Mark.Abraham at anu.edu.au>> wrote:
>
>     On 9/11/2010 8:19 PM, hengame fallah wrote:
>>     Thanks Justin,
>>     actually the protein that i want to simulate consists of two
>>     amino acids: PHE and BOC
>>     BOC is an unusual amino acid as you know.
>>     It has a Cl instead of HZ in PHE and has one extra CH2 in
>>     comparison to PHE
>
>     So that probably means you'll have to pay care to the [bonds]
>     section in the .rtp file. The only bonds GROMACS knows about are
>     the ones in the .rtp. They have to be right. The errors below look
>     like you haven't done it right.
>
>
>>     I finally defined a residue BOC in opls .rtp file:
>>
>>     [ BOC ]
>>      [ atoms ]
>>          N    opls_238   -0.500     1
>>          H    opls_241    0.300     1
>>         CA    opls_224B  -0.005     1
>>        HA1    opls_140    0.060     1
>>        HA2    opls_140    0.060     1
>>         CB    opls_149    0.140     2
>>        HB1    opls_140    0.060     2
>>        CG1    opls_145   -0.115     2
>>        CD1    opls_145   -0.115     3
>>        HD1    opls_146    0.115     3
>>        CD2    opls_145   -0.115     4
>>        HD2    opls_146    0.115     4
>>        CE1    opls_145   -0.115     5
>>        HE1    opls_146    0.115     5
>>        CE2    opls_145   -0.115     6
>>        HE2    opls_146    0.115     6
>>         CZ    opls_145    0.885     7
>>         Cl    opls_264   -1.000     7
>>        CG2    opls_071   -0.005     8
>>        HG1    opls_140    0.060     8
>>        HG2    opls_140    0.060     8
>>          C    opls_235    0.700     9
>>          O    opls_236   -0.700     9
>>
>>     the ending part of my PDB is:
>>     ...
>>     ATOM     38  HE2 PHE     2      -6.946   8.455   4.409
>>     ATOM     39  CZ  PHE     2      -5.456  10.015   4.624
>>     ATOM     40  HZ  PHE     2      -5.887  10.646   3.828
>>     ATOM     41  N   BOC     3      -1.862   5.210   5.333
>>     ATOM     42  H   BOC     3      -2.325   4.344   5.618
>>     ATOM     43  CA  BOC     3      -1.001   5.232   4.169
>>     ATOM     44  HA1 BOC     3      -0.540   6.235   4.026
>
>     HA2 is missing here, per your .rtp
>
>
>>     ATOM     45  CB  BOC     3      -1.797   4.794   2.924
>>     ATOM     46 HB1  BOC     3      -2.244   3.809   3.204
>>     ATOM     47  CG1 BOC     3      -2.976   5.730   2.589
>>     ATOM     48  CG2 BOC     3      -0.935   4.544   1.698
>>     ATOM     49  CD1 BOC     3      -1.231   3.466   0.845
>>     ATOM     50  HD1 BOC     3      -2.070   2.790   1.081
>>     ATOM     51  CD2 BOC     3       0.120   5.408   1.353
>>     ATOM     52  HD2 BOC     3       0.357   6.277   1.986
>>     ATOM     53  CE1 BOC     3      -0.471   3.236  -0.312
>>     ATOM     54  HE1 BOC     3      -0.717   2.381  -0.964
>>     ATOM     55  CE2 BOC     3       0.881   5.182   0.197
>>     ATOM     56  HE2 BOC     3       1.706   5.870  -0.054
>>     ATOM     57  CZ  BOC     3       0.591   4.093  -0.639
>>     ATOM     58  C   BOC     3      -2.565   7.148   2.291
>>     ATOM     59  O   BOC     3      -2.716   8.035   3.131
>>     ATOM     60  CL  BOC     3       1.525   3.816  -2.062
>>     ATOM     61  HA2 BOC     3      -0.172   4.511   4.360
>>     ATOM     62  HG1 BOC     3      -3.530   5.331   1.707
>>     ATOM     63  HG2 BOC     3      -3.708   5.729   3.431
>>
>>     Now i got t this error:
>>     ...
>>     There are 1 chains and 0 blocks of water and 3 residues with 63 atoms
>>
>>       chain  #res #atoms
>>       1 ' '     3     63
>>
>>     All occupancy fields zero. This is probably not an X-Ray structure
>>     Opening library file /usr/share/gromacs/top/ffoplsaa.atp
>>     Atomtype 1
>>     Reading residue database... (ffoplsaa)
>>     Opening library file /usr/share/gromacs/top/ffoplsaa.rtp
>>     Residue 57
>>     Sorting it all out...
>>     Opening library file /usr/share/gromacs/top/ffoplsaa.hdb
>>     Opening library file /usr/share/gromacs/top/ffoplsaa-n.tdb
>>     Opening library file /usr/share/gromacs/top/ffoplsaa-c.tdb
>>
>>     Back Off! I just backed up topol.top to ./#topol.top.69#
>>     Processing chain 1 (63 atoms, 3 residues)
>>     There are 3 donors and 3 acceptors
>>     There are 4 hydrogen bonds
>>     Checking for duplicate atoms....
>>     Opening library file /usr/share/gromacs/top/specbond.dat
>>     7 out of 7 lines of specbond.dat converted succesfully
>>     N-terminus: NH3+
>>     C-terminus: COO-
>>     Now there are 3 residues with 68 atoms
>>     Making bonds...
>>     Warning: Long Bond (52-53 = 0.334847 nm)
>>     Warning: Long Bond (52-55 = 0.334912 nm)
>>     Warning: Long Bond (63-64 = 0.271173 nm)
>>     Warning: Long Bond (63-65 = 0.347808 nm)
>>     Warning: Long Bond (63-66 = 0.31288 nm)
>
>     This is telling you the connectivity in your .rtp doesn't match
>     the spatial arrangement very well. Go back and check the .rtp file.
>
>
>>     Opening library file /usr/share/gromacs/top/aminoacids.dat
>>
>>     -------------------------------------------------------
>>     Program pdb2gmx, VERSION 4.0.7
>>     Source code file: ../../../../src/kernel/add_par.c, line: 233
>>
>>     Fatal error:
>>     Atom HB11 not found in rtp database in residue BOC, it looks a
>>     bit like HB1
>
>     pdb2gmx is probably hopelessly confused by now. Fix the other
>     issues and try again.
>
>     Mark
>
>
>>     -------------------------------------------------------
>>     ...
>>
>>     What should i do?
>>
>>

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