Construction and characterization of a mutant of Rhodobacter sphaeroides with the reaction center as the sole pigment-protein complex

Biochemistry ◽  
1992 ◽  
Vol 31 (18) ◽  
pp. 4458-4465 ◽  
Author(s):  
M. R. Jones ◽  
R. W. Visschers ◽  
R. Van Grondelle ◽  
C. N. Hunter
Keyword(s):  
Reaction Center ◽  
Rhodobacter Sphaeroides ◽  
Protein Complex ◽  
Pigment Protein Complex

Characterization of Reaction Center-B875 Complex of Rhodocyclus gelatinosus: QB Site Properties Derived from Reconstitution Experiments

1991 ◽  
Vol 46 (1-2) ◽  
pp. 99-105 ◽  
Author(s):  
I. Agalidis ◽  
E. Rivas ◽  
F. Reiss-Husson
Keyword(s):  
Reaction Center ◽  
Protein Complex ◽  
Electron Acceptors ◽  
Rhodocyclus Gelatinosus ◽  
Pigment Protein Complex ◽  
Ubiquinone Binding ◽  
Dodecyl Ether ◽  
Particle Weight

Abstract Purified reaction center-B875 pigment-protein complex isolated from Rc. gelatinosus (I. Agalidis, E. Rivas, and F. Reiss-Husson, Photosynth. Res. 23, 249 - 255 (1990)) was further characterized. In the chromatophores, the quinone content was shown to be 6 menaquinones 8 and 16 ubiquinones 8 per reaction center, indicating that the pool contained both quinone types. Besides the primary (MK8) and secondary (UQ8 ) electron acceptors of the reaction cen­ter, the complex contains residual quinones from the membrane pool (about 3 MK8 and 5 UQ8) probably associated with the phospholipids. Apparent particle weight of the complex including bound detergent was 520 ± 46 kDa. The secondary quinone QB was partially removed from the RC by treatment with 2 -3 % octaethyleneglycol dodecyl ether and 3 -4 mᴍ orthophenanthroline. Reconstitution experi­ments showed that UQ6, UQ9 and UQ10 could replace QB but that MK8 and MK9 could not. It was concluded that QB site has a clear specificity towards ubiquinone binding.

scholarly journals Photovoltage generation in enzymatic bio-hybrid architectures

MRS Advances ◽  
2020 ◽  
Vol 5 (18-19) ◽  
pp. 985-990 ◽  
Author(s):  
Michele Di Lauro ◽  
Gabriella Buscemi ◽  
Michele Bianchi ◽  
Anna De Salvo ◽  
Marcello Berto ◽  
...  
Keyword(s):  
Quantum Yield ◽  
Reaction Center ◽  
Rhodobacter Sphaeroides ◽  
Surface Functionalization ◽  
Protein Complex ◽  
Transmembrane Protein ◽  
Photochemical Activity ◽  
Organic Transistors ◽  
Hybrid Architectures ◽  
Infra Red

AbstractMost of the photochemical activity of bacterial photosynthetic apparatuses occurs in the reaction center, a transmembrane protein complex which converts photons into charge-separated states across the membrane with a quantum yield close to unity, fuelling the metabolism of the organism. Integrating the reaction center from the bacterium Rhodobacter sphaeroides onto electroactive surfaces, it is possible to technologically exploit the efficiency of this natural machinery to generate a photovoltage upon Near Infra-Red illumination, which can be used in electronic architectures working in the electrolytic environment such as electrolyte-gated organic transistors and bio-photonic power cells. Here, photovoltage generation in reaction center-based bio-hybrid architectures is investigated by means of chronopotentiometry, isolating the contribution of the functionalisation layers and defining novel surface functionalization strategies for photovoltage tuning.

Spectroscopic Characterization of Two New Reaction Center Mutants of the Photosynthetic Bacterium Rhodobacter Sphaeroides

1998 ◽  
pp. 747-750
Author(s):  
Arjo L. de Boer ◽  
Sieglinde Neerken ◽  
Hjalmar P. Permentier ◽  
Erik Vijgenboom ◽  
Peter Gast ◽  
...  
Keyword(s):  
Reaction Center ◽  
Rhodobacter Sphaeroides ◽  
Photosynthetic Bacterium ◽  
Spectroscopic Characterization

scholarly journals A novel chlorophyll protein complex in the repair cycle of photosystem II

2019 ◽  
Vol 116 (43) ◽  
pp. 21907-21913 ◽  
Author(s):  
Daniel A. Weisz ◽  
Virginia M. Johnson ◽  
Dariusz M. Niedzwiedzki ◽  
Min Kyung Shinn ◽  
Haijun Liu ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Reaction Center ◽  
Protein Complex ◽  
Analytical Ultracentrifugation ◽  
Current Model ◽  
Repair Process ◽  
Native Page ◽  
Multiple Recycling ◽  
Pigment Protein Complex ◽  
Repair Cycle

In oxygenic photosynthetic organisms, photosystem II (PSII) is a unique membrane protein complex that catalyzes light-driven oxidation of water. PSII undergoes frequent damage due to its demanding photochemistry. It must undergo a repair and reassembly process following photodamage, many facets of which remain unknown. We have discovered a PSII subcomplex that lacks 5 key PSII core reaction center polypeptides: D1, D2, PsbE, PsbF, and PsbI. This pigment–protein complex does contain the PSII core antenna proteins CP47 and CP43, as well as most of their associated low molecular mass subunits, and the assembly factor Psb27. Immunoblotting, mass spectrometry, and ultrafast spectroscopic results support the absence of a functional reaction center in this complex, which we call the “no reaction center” complex (NRC). Analytical ultracentrifugation and clear native PAGE analysis show that NRC is a stable pigment–protein complex and not a mixture of free CP47 and CP43 proteins. NRC appears in higher abundance in cells exposed to high light and impaired protein synthesis, and genetic deletion of PsbO on the PSII luminal side results in an increased NRC population, indicative that NRC forms in response to photodamage as part of the PSII repair process. Our finding challenges the current model of the PSII repair cycle and implies an alternative PSII repair strategy. Formation of this complex may maximize PSII repair economy by preserving intact PSII core antennas in a single complex available for PSII reassembly, minimizing the risk of randomly diluting multiple recycling components in the thylakoid membrane following a photodamage event.

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