Identification of 2-deoxy-D-ribono-1,4-lactone at the site of benzophenone photosensitized release of guanine in 2′-deoxyguanosine and thymidylyl-(3′-5′)-2′-deoxyguanosine

Abstract

Benzophenone-mediated photosensitization of 2′-deoxyguanosine (dG) and thymidylyl-(3′-5′)-2′-deoxyguanosine (d(TpG)) at 350 nm in oxygen-saturated aqueous solution produces 2-deoxy-D-ribono-1,4-lactone (dL) and thymidylyl-(3′-5′)-2-deoxy-D-ribono-1,4-lactone (d(TpL)), respectively. These photoproducts have been isolated by reverse phase high-performance liquid chromatography and characterized by proton magnetic resonance spectroscopy and fast atom bombardment mass spectroscopy. Conformational analysis of d(TpG) and d(TpL) in aqueous solution using coupling constant data suggests no major conformational differences between the two dinucleoside monophosphates.