On the wobble(G-T) ⇀ ↽ G-T* (reaction 1) reaction path we observe three regions (see Fig. ). The first region (0-4 Å) largely corresponds to the collective movement of the bases relative to each other as they drift to a Watson-Crick-like bonding angle. In this region, the ∆E is essentially constant as the molecules move over a flat PES in which weak Van der Waals interactions dominate. The fast and activated proton transfer occurs between 4-7.5 Å. In this region, the proton of the Thimine N-H bond first transfers to the oxygen of the carboxylic group of G (as described by the arrow in the transition state of Fig. ). The same proton subsequently hops back to the nearest oxygen of T. Finally, the region of the reaction path closest to the product (> 7.5 Å) corresponds to a further collective translation of the bases toward a Watson-Crick-like configuration, with little rearrangement in the bond of the transferred proton.