[gmx-users] Dihedral restraints

[bharat gupta]

Hi,

I tried restraining two residues of my peptide . The restraints were added
after dihedrals in the top file. Here's how the .top file looks :

[ dihedrals ]
;  ai    aj    ak    al funct            c0            c1
c2            c3
   16     4    18    17     2
   18    16    20    19     2
   25    22    27    26     2
   25    27    22    26     2
   27    25    29    28     2
   27    25    28    29     2
   30    20    32    31     2
   32    30    34    33     2
   37    34    39    38     2
   39    37    41    40     2
   48    46    50    49     2
   48    50    46    49     2
   50    48    52    51     2
   50    52    48    51     2
   52    47    50    53     2
   52    50    47    53     2
   54    41    56    55     2

[ dihedral_restraints ]
; ai   aj    ak    al  type  label  phi  dphi  kfac  power
; phi C'(n-1) - N - CA - C'
  16   18     20    30     1      1  -60     0     5      2
; psi N - CA - C' - N(n+1)
  18   20    30      32     1      1  -30     0     5      2
; phi C'(n-1) - N - CA - C'
  30   32     34    37     1      1  -90     0     5      2
; psi N - CA - C' - N(n+1)
  32    34    37  39  17     1      1  0     0     5      2


I am getting the following error when I used the grompp command :-

Program grompp, VERSION 4.5.4
Source code file: toppush.c, line: 1631

Fatal error:
Incorrect number of parameters - found 4, expected 5 or 5 for Dih. Rest..
For more information and tips for troubleshooting, please check the GROMACS
website at http://www.gromacs.org/Documentation/Errors
-------------------------------------------------------

"You Fill Your Space So Sweet" (F. Apple)



Where did I do the mistake , can anybody guide me in this regard ?? , Also
I don't know what should be the value for power and kfac , what I need is
that the angles should be restrained to what I mentioned in file.

Regards

-- 
Bharat
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