[gmx-users] Distance restraints

[Иванов Миша]

Dear users,

I would like to make a distance restraints. I create a file "disres.itp" with the following content:
[ distance_restraints ]
;  ai    aj    type    index    type    low    up1    up2    fac
  3177  3906     1        1       1      0.0    0.3    0.7    1
where the first atom is form "chain A" of my system and the second is from "SOL".
My question is:
What command should I untroduce in .top file and in what part of it, to make Grompp understand that the first atom is from CHAIN A and the second - from Solvent.
My top file is written below.

Sicerely yours,
Misha Ivanov 

;	This is your topology file
;	?
;
; Include forcefield parameters
#include "ffgmx.itp"

; Include chain topologies
#include "1_A.itp"
#include "1_B.itp"

; Include water topology
#ifdef FLEX_SPC
#include "flexspc.itp"
#else
#include "spc.itp"
#endif

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

[ system ]
; Name
?

[ molecules ]
; Compound        #mols
Protein_A           1
Protein_B           1
SOL               223