Detection of cytochrome b+50 in membranes of Rhodospirillum rubrum isolated from aerobically and phototrophically grown cells
| Autor: | Robert Niederman, Owen T.G. Jones, David E. Mallon, C. N. Hunter |
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| Jazyk: | angličtina |
| Rok vydání: | 1980 |
| Předmět: |
Absorption (pharmacology)
History Cytochrome biology Light Cytochrome b Cytochrome c Rhodospirillum rubrum Cell Membrane Darkness biology.organism_classification Chromatophore Aerobiosis Computer Science Applications Education Membrane Biochemistry Spectrophotometry biology.protein Biophysics Cytochromes Rhodospirillaceae Oxidation-Reduction Research Article |
| Popis: | 1. Dark equilibrium potentiometric titrations were conducted on membranes purified from Rhodospirillum rubrum in an effort to identify b-type cytochrome components reported in other Rhodospirillaceae. In preparations from aerobically grown cells virtually devoid of bacteriochlorophyll a, three components were observed at 560-540 nm. Their oxidation-reduction midpoint potentials assigned by computer-assisted analysis were +195, +50 and −110 mV at pH 7.0; each of these fitted closely to theoretical single-electron equivalent curves. 2. In chromatophores from phototrophically grown carotenoidless mutant G-9, three components were also observed with E0' +190, +50 and −90mV. 3. The alpha-band of the +50mV component exhibited an absorption maximum near 560nm in difference spectra obtained at fixed oxidation-reduction potentials. 4. This component could be demonstrated most readily in purified membrane preparations and may have been obscured in previous studies by residual cytochrome c'. 5. This is the first definitive report of cytochrome b+50 in membranes from Rs. rubrum and aligns this bacterium with other Rhodospirillaceae in which this component functions in light-driven cyclic electron flow. |
| Databáze: | OpenAIRE |
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