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| Molecular mechanism of vectorial proton translocation by bacteriorhodopsin |
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| Author(s): Subramaniam S, Henderson R |
| Source: NATURE Volume: 406 Issue: 6796 Pages: 653-657 Published: AUG 10 2000 |
| Times Cited: 231 References: 28 |
| Abstract: Bacteriorhodopsin, a membrane protein with a relative molecular mass of 27,000, is a light driven pump which transports protons across the cell membrane of the halophilic organism Halobacterium salinarum. The chromophore retinal is covalently attached to the protein via a protonated Schiff base. Upon illumination, retinal is isomerized. The Schiff base then releases a proton to the extracellular medium, and is subsequently reprotonated from the cytoplasm. An atomic model for bacteriorhodopsin was first determined by Henderson et al(1), and has been confirmed and extended by work in a number of laboratories in the last few years(2). Here we present an atomic model for structural changes involved in the vectorial, light-driven transport of protons by bacteriorhodopsin. A 'switch' mechanism ensures the vectorial nature of pumping. First, retinal unbends, triggered by loss of the Schiff base proton, and second, a protein conformational change occurs. This conformational change, which we have determined by electron crystallography at atomic (3.2 Angstrom in-plane and 3.6 Angstrom vertical) resolution, is largely localized to helices F and G, and provides an 'opening' of the protein to protons on the cytoplasmic side of the membrane. |
| Document Type: Article |
| Language: English |
| Reprint Address: Subramaniam, S (reprint author), MRC, Mol Biol Lab, Hills Rd, Cambridge CB2 2QH, England |
Addresses:
1. MRC, Mol Biol Lab, Cambridge CB2 2QH, England
2. NCI, Biochem Lab, Bethesda, MD 20892 USA |
| Publisher: MACMILLAN PUBLISHERS LTD, PORTERS SOUTH, 4 CRINAN ST, LONDON N1 9XW, ENGLAND |
| Subject Category: Multidisciplinary Sciences |
| IDS Number: 342PF |
| ISSN: 0028-0836 |
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| | | | | | | | | Record from Web of Science® | | | | | | | | | |