Pathways of proton transfer in the light-driven pump bacteriorhodopsin

Lanyi, J. K.

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NASA NTRS · 20040112277

Pathways of proton transfer in the light-driven pump bacteriorhodopsin

Lanyi, J. K.

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Abstract

The mechanism of proton transport in the light-driven pump bacteriorhodopsin is beginning to be understood. Light causes the all-trans to 13-cis isomerization of the retinal chromophore. This sets off a sequential and directed series of transient decreases in the pKa's of a) the retinal Schiff base, b) an extracellular proton release complex which includes asp-85, and c) a cytoplasmic proton uptake complex which includes asp-96. The timing of these pKa changes during the photoreaction cycle causes sequential proton transfers which result in the net movement of a proton across the protein, from the cytoplasmic to the extracellular surface.

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NASA Discipline Number 52-30 NASA Discipline Exobiology NASA Program Exobiology Review, Tutorial Review Non-NASA Center Light Proton Pumps/physiology Halobacterium/physiology Bacteriorhodopsins/chemistry/physiology/radiation effects Bacterial Proteins/chemistry/physiology/radiation effects Membrane Potentials/physiology Cell Membrane/physiology Hydrogen-Ion Concentration Cytoplasm/physiology Schiff Bases

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Lanyi, J. K.. 1993-07-05. Pathways of proton transfer in the light-driven pump bacteriorhodopsin. https://ntrs.nasa.gov/citations/20040112277

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