Nuclear quantum effect on the hydrogen-bonded structure of guanine-cytosine pair

Daido, Masashi*; Koizumi, Akihito*; Shiga, Motoyuki   ; Tachikawa, Masanori*

The structure of Watson-Crick type guanine-cytosine (G-C) base pair has been studied by classical hybrid Monte Carlo (HMC) and quantum path integral hybrid Monte Carlo (PIHMC) simulations on the semiempirical potential energy surface. For the three NHX hydrogen-bonded moieties, the intramolecular NH bonds are found systematically longer while the HX distance shorter in the PIHMC simulation than in the HMC simulation. We found that the hydrogen bonded length NX correlates with the HX distance, but not with the NH distance. A correlation is also between the neighboring hydrogen bonds in the G-C base pair.