It has been recently proposed that in addition to bacteriorhodopsin, Halobacterium halobium membranes contain a second light-reactive pigment, whose function is the translocation of sodium ions. The evidence is based on the presence of light-driven, uncoupler-insensitive, sodium ion extrusion and light-driven, uncoupler-enhanced, passive proton uptake in cell envelope vesicles prepared from H....

The purple membrane isolated from Halobacterium halobium contains only a single protein, bacteriorhodopsin, which functions as a light-driven proton pump. Substantial structural information has been obtained which has led to specific models of protein structure in the membrane (Engelman et al., 1982; Huang et al., 1982; Agard & Stroud, 1982). The retinal chromophore of bacteriorhodopsin is boun...

X-ray and electron diffraction studies of specific reaction intermediates, or reaction intermediate analogues, have produced a consistent picture of the structural mechanism of light-driven proton pumping by bacteriorhodopsin. Of central importance within this picture is the structure of the L-intermediate, which follows the retinal all-trans to 13-cis photoisomerization step of the K-intermedi...

We report a comprehensive electron crystallographic analysis of conformational changes in the photocycle of wild-type bacteriorhodopsin and in a variety of mutant proteins with kinetic defects in the photocycle. Specific intermediates that accumulate in the late stages of the photocycle of wild-type bacteriorhodopsin, the single mutants D38R, D96N, D96G, T46V, L93A and F219L, and the triple mut...

Time-resolved, flash-induced difference absorbance spectra (300-700 nm) at pH 10.5 and 5 degrees C for the bacteriorhodopsin photocycle fast and slow decaying forms of the M intermediate (M(f) and M(s), respectively) and R intermediate are reported. The main distinguishing features are as follows: For M(f), DeltaA(max) = 412 nm, a shoulder at 436 nm, no absorbance change at 350 nm; DeltaA(min) ...

Bacteriorhodopsin, a model system in nanobiotechnology, is a light-sensitive protein found in the archaean Halobacterium salinarum and a very identical protein to visual Rhodopsin. The modification of biological function of BR and its versatile properties is valuable for technical applications including the artificial retina. These photoactive elements of native and particular mutants of bacter...

The photochemical behaviour of an analogous bacteriorhodopsin (9,12-Ph-BR) which contains the sterically fixed 9,12-phenylretinal has been investigated with picosecond spectroscopy. The following results have been obtained. No ground-state intermediate photoproduct is found in agreement with the previous observation that 9,12-Ph-BR does not exhibit proton pumping under illumination. The excited...

bioelectronics has attracted increasing interest in recent years because of their applications in various disciplines, such as biomedical. development of efficient bio-nano hybrid materials is a new move towards revolution of nano-bioelectronics. a novel nano-bio hybrid electrode based on zno–protein for bioelectronics applications was prepared and characterized. the electrode was made by coval...