I have a protein and I want to check the orientation of side chain of a particular resdiue A with respect to the residue B in the active site. any help on this regard? currently I am using gmx gangel where group 1 includes the alpha carbon position of B residue and alpha carbon position of A residue and group 2 includes alpha carbon of B and the last atom of the A residue. I am not sure if this is the correct way. any guidance would be appreciated.