Identification, isolation, and sequence of the reaction center protein genes of the photosynthetic purple bacterium Rhodopseudomonas capsulata
Reaction centers in photosynthetic membranes are the centers to which electronic excitation due to light absorption is transferred. This excitation brings about a charge separation between a bacteriochlorophyll molecule and two quinone molecules which ultimately leads to the formation of a hydroquinone. The reduced hydroquinone is then utilized to produce a proton gradient across the membrane and ultimately to produce ATP. We have focused our interest on the structure of the reaction center in the photosynthetic purple bacterium, Rhodopseudomonas capsulata, with the intention of establishing a detailed understanding of these first chemical steps in the natural fixation of sunlight. The methods used to identify and isolate the genes for the three reaction center subunits, L, M, and H, in Rps. capsulata are outlined. These genes have then been sequenced, and the sequences analyzed in detail for their similarity with sequences of comparable proteins from more advanced photosynthetic bacteria such as Anabena, from algae such as Euglena and Chlamydomonas, and from higher plants such as amaranthus, soybean, tobacco and spinach. Homology was found which has been tentatively interpreted to be in the region of quinone binding in all of these reaction centers. There is growing optimism that there will be substantial structural similarity between the reaction centers of the purple bacteria and those of photosystem II in higher plants. This conclusion is important because the x-ray crystal structures of several of the purple bacteria reaction center complexes are presently being worked on and will ultimately be solved.
- Research Organization:
- Lawrence Berkeley Lab., CA (USA)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 6653125
- Report Number(s):
- LBL-18105; CONF-840783-1; ON: DE84016058
- Resource Relation:
- Conference: 9. international congress on photobiology, Philadelphia, PA, USA, 3 Jul 1984; Other Information: Portions are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
PHOTOSYNTHETIC BACTERIA
GENETIC MAPPING
PHOTOSYNTHETIC REACTION CENTERS
CHEMICAL REACTIONS
CHLOROPHYLL
DNA SEQUENCING
GENETICS
PHOTOSYNTHETIC MEMBRANES
QUINONES
AROMATICS
BIOLOGY
CARBOXYLIC ACIDS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
MAPPING
MEMBRANES
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHYTOCHROMES
PIGMENTS
PORPHYRINS
STRUCTURAL CHEMICAL ANALYSIS
140505* - Solar Energy Conversion- Photochemical
Photobiological
& Thermochemical Conversion- (1980-)
550700 - Microbiology