Protein dynamics is intimately related to biological function. Core dynamics is usually studied with 2H spin relaxation of the 13 @entity6076 group, analyzed traditionally with the @entity3628 ( @entity3628 ) approach. We showed recently that @entity3628 is oversimplified in several respects. This includes the assumption that the local motion of the dynamic probe and the global motion of the protein are decoupled, the local geometry is simple, and the local ordering is axially symmetric. Because of these simplifications @entity3628 has yielded a puzzling picture where the @entity5498 rotation axis is moving rapidly with amplitudes ranging from nearly complete disorder to nearly complete order in tightly packed protein cores. Our conclusions emerged from applying to @entity5498 dynamics in proteins the slowly relaxing local structure (SRLS) approach of Polimeno and Freed (Polimeno, A.; Freed, J. H. J. Phys. Chem. 1995, 99, 10995-11006.), which can be considered the generalization of @entity3628 , with all the simplifications mentioned above removed. The SRLS picture derived here for the B1 immunoglobulin binding domain of peptostreptococcal protein L, studied over the temperature range of 15-45 degrees C, is fundamentally different from the @entity3628 picture. Thus, @entity5498 dynamics is characterized structurally by rhombic local potentials with varying symmetries and dynamically by tenfold slower rates of local motion. On average, potential rhombicity decreases, mode-coupling increases, and the rate of local motion increases with increasing temperature. The average activation energy for local motion is 2.0 +/- 0.2 kcal/mol. Mode-coupling affects the analysis even at 15 degrees C. The accuracy of the results is improved by including in the experimental data set relaxation rates associated with rank 2 coherences.

An improved picture of XXXX dynamics in proteins from slowly relaxing local structure analysis of 2H spin relaxation.

@entity5498 :: ('CHEBI:32875', 'Chemical') :: ['methyl'] @entity6076 :: ('1000', 'Gene') :: ['CDH2'] @entity3628 :: ('MESH:D004195', 'Disease') :: ['model-free', 'MF']
@entity5498 :: (CHEBI:32875,Chemical) :: ['methyl']
