SENSITIVITY OF NONCOOPERATIVE BINDING PARAMETERS OF LIGAND-DNA COMPLEX BY COMPUTER-ANALYSIS

A simple user-friendly computer programme has been developed to operat e on an IBM-PC compatible machine to aid in the process of curve fitti ng using the McGhee and von Hippel equation [J. Mol Biol, 86 (1974), 4 69-489] for the analysis of ligand-DNA interactions and the experiment al data on berberine-calf thymus DNA and berberine-poly(dI-dC). poly(d I-dC) for non-cooperative binding. A sensitivity analysis on binding c onstant (K0) and the number of binding sites (N0) show that a small va riation in the latter remarkably alters the fitting curve. At a level of 1% change in N0 from the best fit value, the standard deviation gro ws by almost 4%, while, on the other hand, a 1% change in K0 affects t he same value only by less than 0.4%.