The question was: "I would like to adjust torsion angle CHI5 in Arg residues. I do not see on my dials when I use tor_residue. I tried dial_next. How do i fix this problem ?"

Alwyn replied: "The last angle is fixed because it is a planar group - if you want to distort it, go into the torsion.o file. This will result in a large deviation when you come into your favourite refinement program."