Transient TELC and transmembrane potential in a laser flashed bacteriorhodopsin purple membrane open flat sheet

Abstract

AbstractThe transmembrane-electrostatically localized protons/cations charges (TELC, also known as TELP) model may serve as a unified framework to explain a wide range of bioenergetic phenomenon. Transient TELC and transmembrane potential in a laser flash-energized bacteriorhodopsin (bR) purple membrane (PM) open flat sheet are now better analyzed. Under the Heberle et al. 1994 experimental conditions, the number of bR molecules is now calculated to be 8200 per PM open flat sheet with a diameter of 600 nm. With a single-turnover laser flash intensity of 3 mJ/cm2to photoexcite 10% of the bR molecules, the number of laser flash-induced peak TELC density is calculated to be 2900 per µm2of PM, which translates to a peak transient transmembrane potential of 50 mV. The bR protonic outlet protrudes into the liquid phase outside the putative “potential well/barrier”. The observation is in line with the TELP model; but does not support the “potential well/barrier” model. The author encourages research on more relevant protonic cell systems that have transmembrane potential with TELC comprising excess positive charges at one side and excess anions at the other side of the membrane.