Protein conformational flexibility from structure-free analysis of NMR dipolar couplings: Quantitative and absolute determination of backbone motion in ubiquitin

Abstract

A robust procedure for the determination of proteinbackbone motions on time scales of pico- to milliseconds directly from residual dipolar couplings has been developed that requires no additional scaling relative to external references. The results for ubiquitin (blue in graph: experimental N HN order parameters) correspond closely to the amplitude, nature, and distribution of motion found in a 400 ns molecular-dynamics trajectory of ubiquitin (red). © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.