Signal Transduction in Halobacteria
The search for photosynthetically efficient green light and the avoidance of inefficient blue light or lethal ultra-violet light allows halobacteria to survive by means of photosynthesis in a natural habitat of brines and salt ponds under strong sunlight. The entire photobiochemistry of these archaebacteria is based upon the activation of retinal proteins. Two light-driven ion pumps, bacteriorhodopsin as a proton pump and halorhodopsin as a chloride pump, representlight energy converters that power the energy-driven processes of the cell (Lanyi, 1984). Two light sensors, sensory rhodopsin and protein P480 (also called SR-II or phoborhodopsin) mediate “colour” vision that aids the cell in finding the optimal photosynthetic environment (Spudich & Bogomolni, 1984; Takahashi et al., 1985; Marwan & Oesterhelt, 1987).
KeywordsRetinal Protein Flagellar Motor Microbeam Irradiation Sensory Rhodopsin Halobacterium Halobium
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