Physical Sciences and Mathematics Commons^™

Effect Of Intermolecular Orientation Upon Proton Transfer Within A Polarizable Medium, Steve Scheiner, X. Duan

Steve Scheiner

Ab initio calculations are used to investigate the proton transfer process in bacteriorhodopsin. HN = CH₂ serves as a small prototype of the Schiff base while HCOO^- models its carboxylate-containing counterion and HO^- the hydroxyl group of water of tyrosine, leading to the HCOO^-.H⁺.NHCH₂ and HO^-.H⁺.NHCH₂ complexes. In isolation, both complexes prefer a neutral pair configuration wherein the central proton is associated with the anion. However, the Schiff base may be protonated in the former complex, producing the HCOO^-.⁺HNHCH₂ ion pair, when …