NMR Reveals Enzyme's Dynamic Motion

Nuclear magnetic resonance (NMR) experiments have revealed that enzyme catalysis is a dynamic process that relies on the inherent plasticity of the protein as well as the three-dimensional structure of its active binding site.

Investigators at Brandeis University (Waltham, MA, USA) performed NMR relaxation experiments to study the dynamics of the prolyl cis-trans isomerase cyclophilin A (CypA) in its substrate-free state and during catalysis.

They reported in the November 3, 2005, issue of Nature that the characteristic enzyme motions detected during catalysis were already present in the free enzyme with frequencies corresponding to the catalytic turnover rates. This correlation suggested that the protein motions necessary for catalysis are an intrinsic property of the enzyme and may even limit the overall turnover rate. Motion was localized not only to the active site but encompassed the entire protein molecule.

"This research shifts the paradigm of how we thought proteins work,” explained senior author Dr. Dorothee Kern, professor of biophysics at Brandeis University. "The traditional view is that proteins are not terribly dynamic when they do not perform their function, and that they become dynamic only during catalysis, their active state. What we have learned now is that there is no resting state, that even in the absence of substrates, before catalysis, defined motions of many atoms is an intrinsic property of these enzymes.”




Related Links:
Brandeis University