A Novel Approach to the Retrieval of Structural and Dynamic Information from Residual Dipolar Couplings Using Several Oriented Media in Biomolecular NMR Spectroscopy

The interpretation of residual dipolar couplings in terms of molecular properties of interest is complicated because of difficulties in separating structural and dynamic effects as well as the need to estimate alignment tensor parameters a priori. An approach is introduced here that allows many of these difficulties to be circumvented when data are acquired in multiple alignment media. The method allows the simultaneous extraction of both structural and dynamic information directly from the residual dipolar coupling data, in favorable cases even in the complete absence of prior structural knowledge. Application to the protein ubiquitin indicates greater amplitudes of internal motion than expected from traditional (15)N spin relaxation analysis.