THE DYNAMIC FEATURE OF THE PROTON COLLECTING ANTENNA OF A PROTEIN SURFACE

Abstract The surface of a protein is a condense matrix of proton binding sites having wide range of p K values. In domains where proton uptake is a part of the catalytic cycle, the surface sites endow the region with special kinetic features which represents the ensemble properties of the proton binding sites. Low p K carboxylate can merge their Coulomb cages to form an extended proton trap, where the binding of a proton to one is rapidly followed by shuttling to another. Neutral p K moieties can act as a temporary proton reservoir which delay the proton at the site, enhancing the probability that upon dissociation it will be taken up by the other elements of the active site. These features had been experimentally identified in small model molecules, where detailed kinetic analysis was carried out. On the base of these measurements the dynamics of protonation of the proton entry sites of bacteriorhodopsin and cytochrome oxidase were investigated.