[gmx-users] Re: berger-oplsaa combination for DPC micelle

Low Soo Mei lowsm at bii.a-star.edu.sg
Wed Jun 4 20:42:58 CEST 2008


Hi,

Thank you Chris for the helpful answer!  I have modified the atomtype 
names to follow dmpc.itp, which is more familiar to me, but those names 
are also the same as popc.itp.  There is probably something wrong with 
the way I did it because although the "atomtype not found" errors have 
stopped, I am getting "no default bond types (lines 68-86) / angle types 
(lines 138, 147) / proper dihedral types (lines 161-167)".  My modified 
dpc_double_pairlist.itp file is attached below.

> Message: 7
> Date: Wed, 04 Jun 2008 12:01:33 -0400
> From: chris.neale at utoronto.ca
> Subject: [gmx-users] berger-oplsaa combination for DPC micelle
> To: gmx-users at gromacs.org
> Message-ID: <20080604120133.htonx5kcw8gg8c48 at webmail.utoronto.ca>
> Content-Type: text/plain;	charset=ISO-8859-1;	DelSp="Yes";
> 	format="flowed"
>
> In general, you should always post your relevant files with your  
> question. It makes it easier for us to answer you. That said, I happen  
> to have already used DPC and here is what I have done. I made a new  
> dpc_rename.itp and it is quite different, but should simulate the  
> exact same. Here is the beginning of the atoms section
>
> ;Chris Neale modified atomtype names here to follow popc.itp
> ; Atoms double checked vs. popc.itp by CN Oct5 2006
> [ atoms ]
> ;   nr    type   resnr  residu    atom    cgnr        charge          mass
>       1     LC3       1    DPC      C1       1         0.4       ; qtot: 0.248
>       2     LC3       1    DPC      C2       1         0.4       ; qtot: 0.496
>       3     LC3       1    DPC      C3       1         0.4       ; qtot: 0.744
>       4     LNL       1    DPC      N4       1        -0.5       ; qtot: 0.752
>       5     LH2       1    DPC      C5       1         0.3       ; qtot: 1
>
> and then you need to make modifications to the other sections so that  
> the parameters are found appropriately.
>
> Chris.
>
> -- original message --
>
> Hi Gromacs users,
>
> I am trying to simulate a protein with a micelle, and have used dpc.itp
> from Dr. Tieleman's site.  I have also introduced parts of lipid.itp
> into ffoplsaanb.itp and ffoplsaabon.itp in accordance with Chris Neale's
> half-epsilon double-pairlist method.  But when I issue a grompp command
> for minimization, grompp gives a fatal error that the "Bonded/nonbonded
> atom type 'CH3' not found!".  This atom type CH3 is present in dpc.itp.
> I am now wondering if I can match this to some existing atom in the
> oplsaa and how I might go about choosing which atom.
>
> I would be grateful for your advice, and am happy to attach files if needed.
>
> Cheers,
> Soo Mei
>
>   
; topology for a dodecylphosphocholine lipid from Tieleman's site.
; modified to follow the other pc.itp's on Tieleman's site, as suggested 
by Chris Neale on gmx-users list on 4th June 2008, when I had "atomtype 
not found" problems
[ bondtypes ]
  ; i    j func        b0          kb
  LC3  LNL    1   0.14700       376560. ; formerly CH3 and NL.
;  CH1  OS    1   0.14300       251040. ; no CH1 in DPC.
;  OS    C    1   0.13600       251040. ; no C in DPC.  C is the 
ester-linkage carbon that joins the glycerol backbone to the long lipid 
chains in the pc.itp's.

[ angletypes ]
  ; i    j    k func       th0         cth
  LC3   LNL  LC3    1   109.500      460.00 ; formerly CH3 NL CH3
  LC3   LNL  LH2    1   109.500      460.00 ; formerly CH3 NL CH2
;  CH2  CH1   OS    1   109.500      460.00 ; no CH1 in DPC.
  LNL   LH2  LC2    1   109.500      460.00 ; formerly NL CH2 CH2
    LP   LOS  LC2    1   120.000      397.00 ; formerly P OS CH2.  Can't 
decide if it's 8 7 6 or 8 11 12. Will put for both. This is 8 7 6
    LP   LOS  LP2    1   120.000      397.00 ; and this is 8 11 12.
   LOS    LP   LOM    1   109.600      397.00 ; formerly OS P OM
   LOS    LP   LOS    1   103.000      397.00 ; formerly OS P OS
   LOM    LP   LOM    1   120.000      585.00 ; formerly OM P OM
;   OS  CH2  CH1    1   111.000      460.00 ; no CH1 in DPC.
;  CH2  CH2  CH1    1   111.000      460.00 ; no CH1 in DPC.
  LP2  LP2  LP2    1   111.000      460.00
  LP2  LP2  LP3    1   111.000      460.00
;  CH2  CH1  CH2    1   109.500      460.00 ; no CH1 in DPC.
;  CH1   OS    C    1   120.000     418.00 ; no CH1 or C in DPC.
;  CH2   OS    C    1   120.000     418.00 ; no C in DPC.
;  CH3   OS    C    1   120.000      418.00 ; no C in DPC.
;   OS    C    O    1   124.000      502.00 ; no C in DPC.
;   OS    C  CH2    1   115.000      502.00 ; no C in DPC.
;    O    C  CH2    1   121.000      502.00 ; no C in DPC.
;    C  CH2  CH2    1   120.000      585.00 ; no C in DPC.

[ moleculetype ]
; Name   nrexcl
DPC      3

[ atoms ]
;   nr    type   resnr  residu    atom    cgnr        charge          mass
     1     LC3      1    DPC      C1       1         0.4        ; qtot: 
0.248, type formerly CH3
     2     LC3      1    DPC      C2       1         0.4        ; qtot: 
0.496, type formerly CH3
     3     LC3      1    DPC      C3       1         0.4        ; qtot: 
0.744, type formerly CH3
     4     LNL      1    DPC      N4       1        -0.5        ; qtot: 
0.752, type formerly NL
     5     LH2      1    DPC      C5       1         0.3        ; qtot: 
1, type formerly CH2
     6     LC2      1    DPC      C6       1         0.4        ; qtot: 
1, type formerly CH2
     7     LOS      1    DPC      O7       1        -0.8        ; qtot: 
0.64, type formerly OS
     8     LP       1    DPC      P8       1         1.7        ; qtot: 
1.64, type formerly P
     9     LOM      1    DPC      O9       1        -0.8        ; qtot: 
1, type formerly OM
    10     LOM      1    DPC     O10       1        -0.8        ; qtot: 
0.36, type formerly OM
    11     LOS      1    DPC     O11       1        -0.7        ; qtot: 
0, type formerly OS
    12     LP2      1    DPC     C12       5             0      ; qtot: 
0, type formerly CH2
    13     LP2      1    DPC     C13       6             0      ; qtot: 
0, type formerly CH2
    14     LP2      1    DPC     C14       7             0      ; qtot: 
0, type formerly CH2
    15     LP2      1    DPC     C15       8             0      ; qtot: 
0, type formerly CH2
    16     LP2      1    DPC     C16       9             0      ; qtot: 
0, type formerly CH2
    17     LP2      1    DPC     C17      10             0      ; qtot: 
0, type formerly CH2
    18     LP2      1    DPC     C18      11             0      ; qtot: 
0, type formerly CH2
    19     LP2      1    DPC     C19      12             0      ; qtot: 
0, type formerly CH2
    20     LP2      1    DPC     C20      13             0      ; qtot: 
0, type formerly CH2
    21     LP2      1    DPC     C21      14             0      ; qtot: 
0, type formerly CH2
    22     LP2      1    DPC     C22      15             0      ; qtot: 
0, type formerly CH2
    23     LP3      1    DPC     C23      16             0      ; qtot: 
0, type formerly CH3

[ bonds ]
;  ai    aj funct
    1     4     1
    2     4     1
    3     4     1
    4     5     1
    5     6     1
    6     7     1
    7     8     1
    8     9     1
    8    10     1
    8    11     1
   11    12     1
   12    13     1
   13    14     1
   14    15     1
   15    16     1
   16    17     1
   17    18     1
   18    19     1
   19    20     1
   20    21     1
   21    22     1
   22    23     1

[ pairs ]
;  ai    aj funct
; Here is the first copy.
    1     6     1
    2     6     1
    3     6     1
    4     7     1
    5     8     1
    6     9     1
    6    10     1
    6    11     1
    7    12     1
    8    13     1
    9    12     1
   10    12     1
   11    14     1
;   12    15     1
;   13    16     1
;   14    17     1
;   15    18     1
;   16    19     1
;   17    20     1
;   18    21     1
;   19    22     1
;   20    23     1
; Here is the second copy.  Only use this with the halved LJ-14 epsilon 
values.
    1     6     1
    2     6     1
    3     6     1
    4     7     1
    5     8     1
    6     9     1
    6    10     1
    6    11     1
    7    12     1
    8    13     1
    9    12     1
   10    12     1
   11    14     1


[ angles ]
;  ai    aj    ak funct
    1     4     2     1
    1     4     3     1
    1     4     5     1
    2     4     3     1
    2     4     5     1
    3     4     5     1
    4     5     6     1
    5     6     7     1
    6     7     8     1
    7     8     9     1
    7     8    10     1
    7     8    11     1
    9     8    10     1
    9     8    11     1
   10     8    11     1
    8    11    12     1
   11    12    13     1
   12    13    14     1
   13    14    15     1
   14    15    16     1
   15    16    17     1
   16    17    18     1
   17    18    19     1
   18    19    20     1
   19    20    21     1
   20    21    22     1
   21    22    23     1

[ dihedrals ]
;  ai    aj    ak    al funct
    1     4     5     6     1
    4     5     6     7     1
    5     6     7     8     1
    6     7     8     9     1
    7     8    11    12     1
    8    11    12    13     1
   11    12    13    14     1
   12    13    14    15     3
   13    14    15    16     3
   14    15    16    17     3
   15    16    17    18     3
   16    17    18    19     3
   17    18    19    20     3
   18    19    20    21     3
   19    20    21    22     3
   20    21    22    23     3




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