From NMR Relaxation to fractional Brownian dynamics in proteins: results from molecular dynamics simulations and virtual experiments

by Dr Paolo Calligari (Ecole Normale Superieure Department of Chemistry - NMR Group Paris, France)

Wednesday 4 Jul 2012, 15:00 → 16:00 Europe/Rome

Aula Rasetti (Dipartimento di Fisica - Ed. G. Marconi)

NMR 15N relaxation experiments on isotopically labeled proteins are widely used to probe protein dynamics. Relaxation rates obtained from these experiments can be analyzed to derive motional amplitudes and time scales of protein internal motions but their evaluation is often faced to the difficulty of unambiguously extracting these dynamical parameters without significant simplifying assumptions. We present here an original analysis of NMR relaxation rates based on a multiscale description given by the fractional Ornstein-Ulenbeck process. Our approach is tested against synthetic relaxation rates obtained by molecular dynamics simulations. The concrete study of 15N R1, R2 and NOE rates from two proteins, ubiquitin and 6PGL, give us the chance to compare our approach with the well-known method by Lipari and Szabo.