[gmx-users] Residue 'FE' not found in residue topology database

[E.Elavazhagan]

Hai,
I am having the trouble to obtain the topology file while 
attaching the prosthetic group to the target protein.Heme 
ion is surrounded by the three aminoacids 
 HIS243,ASP185,HIS183 which all are within 3 A' 
distance.While I am using the G43a1 force filed ,the error 
is obtained as   "Residue 'FE' not found in residue 
topology database".On referring the files FFG43a1,ions in 
"C:\cygwin\usr\local\gromacs\share\gromacs\top" we found 
the presence of FE with the mass details. On trying to get 
the top file from the DUNDEE PRODRG server ,I faced the 
error as too many atoms in this molecule.It will be more 
worthful if i come to know how to tackle this problem  or 
possible way to obtain the .top file information in any 
other specific databases.

Thanking You.