An empirical relationship between rotational correlation time and solvent accessible surface area

Structure–dynamics interrelationships are important in understanding protein function. We have explored the empirical relationship between rotational correlation times (τc and the solvent accessible surface areas (SASA) of 75 proteins with known structures. The theoretical correlation between SASA and τc through the equation SASA = Krτc(2/3) is also considered. SASA was determined from the structure, τccalc was determined from diffusion tensor calculations, and τcexpt was determined from NMR backbone13 C or 15N relaxation rate measurements. The theoretical and experimental values of τc correlate with SASA with regression analyses values of Kr as 1696 and 1896 m2s-(2/3), respectively, and with corresponding correlation coefficients of 0.92 and 0.70.