; Include forcefield parameters
#include "ffG43a1.itp"

[ moleculetype ]
; Name nrexcl
DRG      3
[ atoms ]
;   nr      type  resnr resid  atom  cgnr   charge     mass
     1       CH3     1  DRG     CAD     1    0.014  15.0350   
     2       CH2     1  DRG     CAA     1    0.037  14.0270   
     3       CH2     1  DRG     CAB     1    0.037  14.0270   
     4        OA     1  DRG     OAC     1   -0.116  15.9994   
     5        HO     1  DRG     HAA     1    0.028   1.0080   
[ bonds ]
; ai  aj  fu    c0, c1, ...
   1   2   1    0.153    334720.0    0.153    334720.0 ;   CAD  CAA   
   2   3   1    0.153    334720.0    0.153    334720.0 ;   CAA  CAB   
   3   4   1    0.143    334720.0    0.143    334720.0 ;   CAB  OAC   
   4   5   1    0.100    313800.0    0.100    313800.0 ;   OAC  HAA   
[ pairs ]
; ai  aj  fu    c0, c1, ...
   1   4   1                                           ;   CAD  OAC   
   2   5   1                                           ;   CAA  HAA   
[ angles ]
; ai  aj  ak  fu    c0, c1, ...
   1   2   3   1    111.0       460.2    111.0       460.2 ;   CAD  CAA  CAB   
   2   3   4   1    109.5       460.2    109.5       460.2 ;   CAA  CAB  OAC   
   3   4   5   1    109.5       397.5    109.5       397.5 ;   CAB  OAC  HAA   
[ dihedrals ]
; ai  aj  ak  al  fu    c0, c1, m, ...
   4   3   2   1   1      0.0    5.9 3      0.0    5.9 3 ; dih   OAC  CAB  CAA  CAD   
   2   3   4   5   1      0.0    1.3 3      0.0    1.3 3 ; dih   CAA  CAB  OAC  HAA   
 
; Include Position restraint file
#ifdef POSRES
#include "posre.itp"
#endif

; Include water topology
#include "spc.itp"

#ifdef POSRES_WATER
; Position restraint for each water oxygen
[ position_restraints ]
;  i funct       fcx        fcy        fcz
   1    1       1000       1000       1000
#endif

; Include generic topology for ions
#include "ions.itp"
[ system ]
; Name
DRG

[ molecules ]
; Compound        #mols
DRG               100