Study of protein dynamics in solution by measurement of 13C?-13CO NOE and 13CO longitudinal relaxation

Abstract

¹³C^α-¹³CO homonuclear NOE and ¹³CO T₁ relaxation were measured for a 20 kDa protein using tripleresonance pulse sequences. The experiments were sufficiently sensitive to obtain statistically significant differences in relaxation parameters over the molecule. The ¹³C^α-¹³CO cross-relaxation rate, obtained from these data, is directly proportional to an order parameter describing local motion and it is largely independent of the local correlation time. It is therefore a relatively straightforward observable for the identification of local dynamics.