The hydrogen bond energy on mismatched base pair formation between uracil derivatives and guanine in the gas phase and in the aqueous phase

The substitution effect on hydrogen bond energies of the mismatched base pa irs between some uracil derivatives (U-X) and guanine (G) was studied in mo lecular orbital theory (MP2/6-31G*//HF/6-31G* level). The substituent effec t of UX on G-U-X mismatched base pair formation energy was small, though th e base pair formation energy between adenine (A) and U-X, which is a normal type of the Watson-Crick type base pair, was enforced by 1.5 kcal/mol upon introducing an electron-withdrawing group (EWG) into U. Thus, U-X having E WG is more likely to selectively form a base pair with A. Namely, introduct ion of EWG does not change selectivity of the Watson-Crick type base pair f ormation of U. (C) 2000 Elsevier Science B.V. All rights reserved.