[gmx-users] How i can use amber heme ff in gromacs

[Rana Rehan Khalid]

I have force field for Heme Fe----O2 that are amber .prm file how can i use
it in combination of Amber99 ff. because when i run the simulation with
amber99 this error come"""" Residue 'HEM' not found in residue topology
database""""
 while now i have specific ff for fe---o2 bond heme file that is .prm file
kindly guide me how i use this amber .prm file  in gromacs in combination
with amber99