I am using PyMol for modeling a peptide containing D-aminoacid (D-Proline) residue. I could invert the configuration arounf L-Proline to convert it to D-Proline. But, I want the "Phi" of the Proline to adopt a certain value. When i tried using the torsion command by selecting the bond N-CA of the D-Proline residue, there is no change at all. I want the Phi value to change from -60 deg to +60 deg and use this as the model for further analysis. Also, the "Psi" needs to fixed at 120 deg. Is it possible in any way to carry out the same steps and achieve the desired results in Chimera. Any suggestions on how to carry out this would be highly appreciated. -- U.S.Raghavender, PhD Postdoctoral Fellow SRI International 140 Research Drive Harrisonburg, VA 22802 540.438.6643