How Much hydration is necessary for the stabilisation of DNA-duplex?

Abstract
A combination of NOESY and ROESY experiments show that the higher stabilities (T m ) of phenazlne tethered matched (2) and G-A mismatched (4) DNA duplexes are due to the decrease of the exchange-rate (I.e. Increase of the life-time) of the Imlno-protons and the reduced water activity In their minor grooves compared to their non-tethered counterparts (1) and (3).