Proton transfer studies in CGC+ assembly

We have designed and analyzed a molecular model of a generic triple helix DNA base structure - the cytosine-guanine-cytosine (CGC+) assembly. The complex has been investigated for the ability of a concerted proton transfer from cytosine to guanine. Ab initio calculations have been preformed using Unrestricted Hartree-Fock (UHF) method with 6-31G∗+ basis set. In order to determine possible reaction paths, the potential map has been constructed pointing the most stable configuration for the process to occur. Based on this observation, we have estimated a transmission coefficient for the transfer and found no support for a concerted motion. The effect of fluctuations of the barrier height on the kinetics is also discussed.