[gmx-users] Gromos Parameters for Heme bound Oxygen

[Olaniyi Yusuff]

Dear gmx users,
I would like to know if any one has parameters for oxygen or 
carbonmonoxide bound to the heme in hemoglobin.
I am running MD simulations on hemoglobin using the gromos force field 
G43a1 in gromacs, i had no problem when i used the pdb structure for 
pure hemoglobin, but when i try to convert the pdb structure files for 
the liganded hemoglobin (both oxy- and carbonmonoxy- ), there was 
complain of my oxy and carbomonoxy residue unknown i.e not defined in 
the .rtp file.
so i would like to know if there is anyone with parameters for these 
kind of heme in gromacs or better still another reference of force field 
with parameters for them that can be use in gromacs.

Thanks

Kamil yusuff
Deparment of Chemistry,
University of Ibadan ,Nigeria.