Combined Analysis of ~(15)N Relaxation Data from Solid- and Solution-State NMR Spectroscopy

摘要

Nanosecond time-scale backbone dynamics in proteins has been a subject of much interest. While these motions can be detected by solution ~(15)N relaxation methods, they tend to be masked by the overall protein tumbling. As pointed out by Chen et al., "sometimes nanosecond time scale motions with a corresponding squared order parameter as low as 0.9 can go undetected, even with good quality data available at two magnetic fields". The situation can be improved if relaxation data are augmented by residual dipolar couplings (RDCs). This approach, however, is experimentally demanding and the interpretation is complicated by "structural noise", lack of absolute reference, and possible coupling between internal dynamics and alignment.