Fig. 32
From: Ultra-high resolution X-ray structure of orthorhombic bovine pancreatic Ribonuclease A at 100K
Torsion angles for His-119, the blue trace is the MD simulation of orthorhombic RNase A and the orange line is the crystallographically observed value. A C-CA-CB-CG torsion angle, B CA-CB-CG-ND1 torsion angle. The structure has just migrated to the second minimum and stays there because the movement of the protein hasn’t given it the energy to jump back. It doesn’t make any extra hydrogen bonds in this position and is just a consequence of thermal motion. If we extended the simulation to much longer time scales, we would expect to see many more of these events