Standard errors or asymmetric confidence intervals of the protein-ligand binding constant

Abstract

The determination of equilibrium binding constants (Kb) between chemical compounds (ligands) and target proteins in vitro is important for the understanding of biological interaction mechanisms. Accuracy of the data is critical for decision-making in many scientific fields. The Kb is commonly assumed to follow a symmetric normal, Gaussian, distribution, and is often reported as experimental value plus/minus standard deviation. However, in general, the distributions of the measured Kb values (and the equivalent dissociation constant, Kd=1/Kb) and the corresponding Gibbs energy change (ΔGb=-RTlnKb) are all asymmetric to varying degrees.