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 (τ_c) and the solvent accessible surface areas (SASA) of 75 proteins with known structures. The theoretical correlation between SASA and τ_c through the equation SASA = K_ττ^(2/3) _c is also considered. SASA was determined from the structure, τ^calc _c was determined from diffusion tensor calculations, and τ^expt _c was determined from NMR backbone ¹³C or ¹⁵N relaxation rate measurements. The theoretical and experimental values of τ_c correlate with SASA with regression analyses values of K_r as 1696 and 1896 m²s^-(2/3), respectively, and with corresponding correlation coefficients of 0.92 and 0.70.