Cisplatin Changes the Mechanics of Single DNA Molecules

Single-molecule force spectroscopy as an analytical tool offers the unique potential to study the close correlation between force and structure on single molecules. The use of this technique to obtain new information about the interaction of DNA with other molecules is demonstrated here, and shows the special role of force as a steering parameter in biological function. Measurements on natural and synthetic DNA molecules showed that the B-S transition is very sensitive to the binding of cisplatin, and leads to a reduced cooperativity in all molecules with difunctional cisplatin adducts. This latter effect was ascribed to the altered base-stacking interaction caused by cisplatin.