The Role of Proton Transport in Gating Current in a Voltage Gated Ion Channel, as Shown by Quantum Calculations

Alisher M Kariev; Michael E Green

While this type of cyclic analysis adds information, interpretation may require care because of the possible involvement of more residues than the two or three that are considered. The nature of the interaction may involve small conformational changes (side chain shifts, for example, even if the S4 backbone remains stationary) as well as electrostatic interactions, and rearrangements of hydrogen bonding, in addition to proton transfers. The triad that we discuss later shows how interactions may be complex, and the triad does not exist in isolation; if a proton is transferred, it would have to proceed through more residues. Our triad is linked through one member to another triad, or the two groups could be thought of as one pentad, with the five amino acids as a single entity acting to transfer a proton.