Selective Bond Cleavage in Potassium Collisions with Pyrimidine Bases of DNA

Abstract

Electron transfer in alkali-molecule collisions to gas phase thymine and uracil yielding H- formation is selectively controlled in the energy range between 5.3 and 66.1 eV. By tuning the collision energy, electron transfer from the alkali to partly deuterated thymine, methylated thymine at the N-1 and methylated uracil at the N-3 positions, H- loss proceeds not only through the breaking of the (C-H) against (N-H) bonds but also through N-1 against N-3 sites. Such selectivity, as far as bond and site are concerned, is here reported for the first time by electron transfer induced dissociation experiments in alkali-molecule collisions.