Characterization of collective and anisotropic reorientational protein dynamics

Intramolecular reorientational dynamics of proteins are described in terms of reorientational quasiharmonic modes. These modes provide important insig ht into anisotropic and collective axial fluctuations of distinct molecular fragments, and they represent a highly compact description of intramolecul ar protein motions that are spectroscopically observable via nuclear spin r elaxation. The method is applied to a molecular dynamics computer simulatio n of the protein ubiquitin.