Spin-diffusion couples proton relaxation rates for proteins in exchange with a membrane interface.

ABSTRACT: Changes in nuclear spin-lattice relaxation rates that are induced by a freely diffusing paramagnetic relaxation agent are examined for a protein in solution and compared to the case where the protein binds to a membrane. In the solution case, the intramolecular cross-relaxation rates are modest and large differences are observed in the oxygen induced protein-proton relaxation rates. In the case where a dynamic equilibrium between solution and membrane-bound environments is established, the intramolecular (1)H cross-relaxation rates for the protein protons increase dramatically because of the slow reorientational motion in the membrane-bound environment. As a consequence, all protein protons relax with nearly the same spin-lattice relaxation rate constants when bound to the membrane, and si

SUBMITTER: Bhowmik A 

PROVIDER: S-EPMC2581927 | biostudies-literature | 2008 Oct

REPOSITORIES: biostudies-literature