Properties of photosynthetic reaction centers isolated from chromatophores of Chromatium minutissimum

Shinkarev, Vladimir P.; Verkhovsky, Michael I.; Sabó, Ján; Захарова, Н. И.; Kononenko, A.A.

doi:10.1016/0005-2728(91)90015-g

Cited by 6 publications

(6 citation statements)

References 36 publications

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“…6 s, comparable to the lifetime of 8 s in Chr. minutissimum [35], but significantly longer than the lifetimes observed for Rps. viridis and Rb.…”

Section: Kbp)mentioning

confidence: 62%

“…Refs. 35,39). Addition of UQ10 instead of UQ6, did not increase the relative contribution of the slow phase in RC/LH I complexes.…”

Section: Kbp)mentioning

confidence: 95%

“…viridis [33][34] (also in the presence of o-phenanthroline), indicating that the slow phase of P+QA recombination with an amplitude < 9% in the E. mobilis RCs (Fig. 1A) [20,35,36].…”

Section: P +Q~ Charge Recombination Kinetics At Room Temperaturementioning

confidence: 99%

“…Strikingly, loss of QB during isolation is reported for many photosynthetic bacteria that possess a mixed system of quinone electron acceptors in the RC [22,35,36,[45][46][47]. Bacteria containing ubiquinone for both QA and QB appear to have a more stable QB site [48].…”

Section: Nature Of Primary and Secondary Quinone And Quinone Bindingmentioning

confidence: 99%

“…Direct recombination has been suggested for Chr. minutissimum at low pH [35], and for mutants of Rb. sphaeroides in which the ionizable amino acids Glu TM and/or Asp TM have been changed to respectively Gin and Asn [40].…”

Section: P + Q~ Charge Recombination Kineticsmentioning

confidence: 99%

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Properties of the primary and secondary quinone electron acceptors in RC/LH1 complexes from the purple sulfur bacterium Ectothiorhodospira mobilis

Leguijt

Parot

Vermeglio

et al. 1993

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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Properties of the primary and secondary quinone electron acceptors in RC/LH1 complexes from the purple sulfur bacterium Ectothiorhodospira mobilis. Leguijt, T.; Parot, P.; Vermeglio, A.; Crielaard, W.; Hellingwerf, K.J. Published in:Biochimica et Biophysica Acta G General Subjects Link to publication Citation for published version (APA):Leguijt, T., Parot, P., Vermeglio, A., Crielaard, W., & Hellingwerf, K. J. (1994). Properties of the primary and secondary quinone electron acceptors in RC/LH1 complexes from the purple sulfur bacterium Ectothiorhodospira mobilis. Biochimica et Biophysica Acta G General Subjects, 1183, 292-300. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Reaction centers (RCs)with one antenna complex attached (RC/LH~ complexes)were isolated from the alkaliphilic and moderately halophilic, phototrophic purple sulfur bacterium Ectothiorhodospira (E.) mobilis and analyzed with respect to quinone composition and charge recombination kinetics, using time-resolved (low-and room-temperature) spectroscopy and thin-layer chromatography. The RCs contain menaquinone as primary and ubiquinone as secondary quinone electron acceptor, QA and Q a, respectively. Q B is lost during isolation of the RC/LH I complexes. P+ QA charge recombination kinetics, which were shown to be pH independent, were only slightly temperature dependent, indicating that this recombination proceeds via the direct (electron tunnelling) route. At room temperature, its average lifetime was 34.5 ms. These decay kinetics were shown to be monophasic at room temperature and biphasic at low temperature. Addition of an excess of UQ 6 to RC/LH I complexes resulted in retardation of the P+ recovery, due to charge recombination of the state P+QAQa. Functional reconstitution of QB was also evident from flash-induced binary oscillations at 450 nm, which could be observed in RC/LH I complexes in the presence of an excess of UQ 6. This reconstitution of QB activity was, however, incomplete and decreased with increasing pH. The P+QAQB decay kinetics were pH independent; the average lifetime was about 6 s at room temperature. The apparent equilibrium constant g 2 between the states QAQB and QAQB, and consequently the free energy difference between these states, were relatively large and pH independent...

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“…6 s, comparable to the lifetime of 8 s in Chr. minutissimum [35], but significantly longer than the lifetimes observed for Rps. viridis and Rb.…”

Section: Kbp)mentioning

confidence: 62%

“…Refs. 35,39). Addition of UQ10 instead of UQ6, did not increase the relative contribution of the slow phase in RC/LH I complexes.…”

Section: Kbp)mentioning

confidence: 95%

“…viridis [33][34] (also in the presence of o-phenanthroline), indicating that the slow phase of P+QA recombination with an amplitude < 9% in the E. mobilis RCs (Fig. 1A) [20,35,36].…”

Section: P +Q~ Charge Recombination Kinetics At Room Temperaturementioning

confidence: 99%

Section: Nature Of Primary and Secondary Quinone And Quinone Bindingmentioning

confidence: 99%

Section: P + Q~ Charge Recombination Kineticsmentioning

confidence: 99%

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Properties of the primary and secondary quinone electron acceptors in RC/LH1 complexes from the purple sulfur bacterium Ectothiorhodospira mobilis

Leguijt

Parot

Vermeglio

et al. 1993

Biochimica et Biophysica Acta (BBA) - Bioenergetics

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Reaction Center Associated Cytochromes

Nitschke

Dracheva

Advances in Photosynthesis and Respiration

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Flash-induced proton transfer in photosynthetic bacteria

Maróti

1993

Photosynth Res

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A proton electrochemical potential across the membranes of photosynthetic purple bacteria is established by a light-driven proton pump mechanism: the absorbed light in the reaction center initiates electron transfer which is coupled to the vectorial displacement of protons from the cytoplasm to the periplasm. The stoichiometry and kinetics of proton binding and release can be tracked directly by electric (glass electrodes), spectrophotometric (pH indicator dyes) and conductimetric techniques. The primary step in the formation of the transmembrane chemiosmotic potential is the uptake of two protons by the doubly reduced secondary quinone in the reaction center and the subsequent exchange of hydroquinol for quinone from the membrane quinone-pool. However, the proton binding associated with singly reduced promary and/or secondary quinones of the reaction center is substoichiometric, pH-dependent and its rate is electrostatically enhanced but not diffusion limited. Molecular details of protonation are discussed based on the crystallographic structure of the reaction center of purple bacteriaRb. sphaeroides andRps. viridis, structure-based molecular (electrostatic) calculations and mutagenesis directed at protonatable amino acids supposed to be involved in proton conduction pathways.

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Properties of photosynthetic reaction centers isolated from chromatophores of Chromatium minutissimum

Cited by 6 publications

References 36 publications

Properties of the primary and secondary quinone electron acceptors in RC/LH1 complexes from the purple sulfur bacterium Ectothiorhodospira mobilis

Properties of the primary and secondary quinone electron acceptors in RC/LH1 complexes from the purple sulfur bacterium Ectothiorhodospira mobilis

Reaction Center Associated Cytochromes

Flash-induced proton transfer in photosynthetic bacteria

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