Abstract
The membrane protein bacteriorhodopsin (BR) can be kept soluble in its native state for months in the absence of detergent by amphipol (APol) A8-35, an amphiphilic polymer. After an actinic flash, A8-35-complexed BR undergoes a complete photocycle, with kinetics intermediate between that in detergent solution and that in its native membrane. BR/APol complexes form well defined, globular particles comprising a monomer of BR, a complete set of purple membrane lipids, and, in a peripheral distribution, approximately 2 g APol/g BR, arranged in a compact layer. In the absence of free APol, BR/APol particles can autoassociate into small or large ordered fibrils.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Bacterial Proteins / chemistry
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Bacterial Proteins / metabolism
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Bacteriorhodopsins / chemistry*
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Bacteriorhodopsins / metabolism*
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Chromatography, Gel
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Colloids / chemistry
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Color
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Halobacterium salinarum / metabolism
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Lipids / chemistry
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Microscopy, Electron
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Neutron Diffraction
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Polymers / chemistry*
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Polymers / metabolism*
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Propylamines / chemistry*
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Propylamines / metabolism*
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Protein Structure, Secondary
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Purple Membrane / chemistry
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Purple Membrane / metabolism
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Scattering, Small Angle
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Thioglucosides / chemistry
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Ultracentrifugation
Substances
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Bacterial Proteins
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Colloids
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Lipids
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Polymers
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Propylamines
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Thioglucosides
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amphipol A8-35
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Bacteriorhodopsins
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n-octyl-beta-D-thioglucopyranoside