[gmx-users] help on converting charmm/cgenff parameters to gromacs

Peter C. Lai pcl at uab.edu
Thu Apr 7 13:38:13 CEST 2011

Ok here's a minor? problem I'm having with dihedrals.

Apparently grompp won't read H-H dihedrals such as:

HGA2   CG321  CG321  HGA2           9       0.00    0.92048 3 ;LIPID alkane
HGA2   CG321  CG331  HGA3           9       0.00    0.66944 3 ;PROT rotation barrier in ethane
(the lipid equiv would be: HAL2 CTL2 CTL2 HAL2)

it only seems to work if I use
X CG321 CG321 X
but that always seems a bit too broadspectrum...

I'm not using heavy H or anything, just a normal pdb2gmx and normal grompp
but it complains about the H-H dihedrals as "No default Proper Dih. types"...

Any ideas?
Peter C. Lai                 | University of Alabama-Birmingham
Programmer/Analyst           | BEC 257
Genetics, Div. of Research   | 1150 10th Avenue South
pcl at uab.edu                  | Birmingham AL 35294-4461
(205) 690-0808               |

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