書誌事項
- 公開日
- 1995-07-07
- DOI
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- 10.1126/science.7604281
- 公開者
- American Association for the Advancement of Science (AAAS)
この論文をさがす
説明
<jats:p> In the light-driven proton pump bacteriorhodopsin, proton transfer from the retinal Schiff base to aspartate-85 is the crucial reaction of the transport cycle. In halorhodopsin, a light-driven chloride ion pump, the equivalent of residue 85 is threonine. When aspartate-85 was replaced with threonine, the mutated bacteriorhodopsin became a chloride ion pump when expressed in <jats:italic>Halobacterium salinarium</jats:italic> and, like halorhodopsin, actively transported chloride ions in the direction opposite from the proton pump. Chloride was bound to it, as revealed by large shifts of the absorption maximum of the chromophore, and its photointermediates included a red-shifted state in the millisecond time domain, with its amplitude and decay rate dependent on chloride concentration. Bacteriorhodopsin and halorhodopsin thus share a common transport mechanism, and the interaction of residue 85 with the retinal Schiff base determines the ionic specificity. </jats:p>
収録刊行物
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- Science
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Science 269 (5220), 73-75, 1995-07-07
American Association for the Advancement of Science (AAAS)
