Molecular‐dynamics simulation of phenylalanine transfer RNA. II. Amplitudes, anisotropies, and anharmonicities of atomic motions

The atomic motions from a molecular‐dynamics simulation of yeast tRNA Phe are analyzed and compared with those observed in protein simulations. In general, the tRNA motions are of larger amplitude, they are more anisotropic, and they arise from potentials of mean force that are more anharmonic than in the protein case. In both cases, the amplitudes are largest for atoms on the surface of the molecules. On the other hand, the most anisotropic and anharmonic atomic motions are generally found in the interior of the tRNA, while they are found on the surface of the protein. These differences are discussed in terms of the differences in structure between nucleic acids and proteins.