Mode of binding of camptothecins to double helix oligonucleotidesElectronic supplementary information (ESI) available: Chemical shift values, inter-proton distances obtained from MD simulations of CAP model for the complex d(CGTATACG)2/Cpt 6 and molecular dynamics figures. See http://www.rsc.org/suppdata/ob/b3/b312780j/Dedicated to Professors Luciano Caglioti and Domenico Misiti on occasion of their 70th birthdays.