DNA-cisplatin binding mechanism peculiarities studied with single molecule stretching experiments

We propose a method to determine the DNA-cisplatin binding mechanism peculiarities by monitoring the mechanical properties of these complexes. To accomplish this task, we have performed single molecule stretching experiments by using optical tweezers, from which the persistence and contour lengths of the complexes can be promptly measured. The persistence length of the complexes as a function of the drug total concentration in the sample was used to deduce the binding data, from which we show that cisplatin binds cooperatively to the DNA molecule, a point which so far has not been stressed in binding equilibrium studies of this ligand. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3689774]