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Genetically engineered mutant of the cyanobacterium Synechocystis 6803 lacks the photosystem II chlorophyll-binding protein CP-47

Genetically engineered mutant of the cyanobacterium Synechocystis 6803 lacks the photosystem II... CP-47 is absent in a genetically engineered mutant of cyanobacterium Synechocystis 6803, in which the psbB gene encoding the chlorophyll-binding photosystem II (PSII) protein CP-47 was interrupted. Another chlorophyll-binding PSII protein, CP-43, is present in the mutant, and functionally inactive PSII-enriched particles can be isolated from mutant thylakoids. We interpret these data as indicating that the PSII core complex of the mutant still assembles in the absence of CP-47. The mutant lacks a 77 K fluorescence emission maximum at 695 nm, suggesting that the PSII reaction center is not functional. The absence of primary photochemistry was indicated by EPR and optical measurements: no chlorophyll triplet originating from charge recombination between P680+ and Pheo- was observed in the mutant, and there were no flash-induced absorption changes at 820 nm attributable to chlorophyll P680 oxidation. These observations lead us to conclude that CP-47 plays an essential role in the activity of the PSII reaction center. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Proceedings of the National Academy of Sciences PNAS

Genetically engineered mutant of the cyanobacterium Synechocystis 6803 lacks the photosystem II chlorophyll-binding protein CP-47

Genetically engineered mutant of the cyanobacterium Synechocystis 6803 lacks the photosystem II chlorophyll-binding protein CP-47

Proceedings of the National Academy of Sciences , Volume 83 (24): 9474 – Dec 1, 1986

Abstract

CP-47 is absent in a genetically engineered mutant of cyanobacterium Synechocystis 6803, in which the psbB gene encoding the chlorophyll-binding photosystem II (PSII) protein CP-47 was interrupted. Another chlorophyll-binding PSII protein, CP-43, is present in the mutant, and functionally inactive PSII-enriched particles can be isolated from mutant thylakoids. We interpret these data as indicating that the PSII core complex of the mutant still assembles in the absence of CP-47. The mutant lacks a 77 K fluorescence emission maximum at 695 nm, suggesting that the PSII reaction center is not functional. The absence of primary photochemistry was indicated by EPR and optical measurements: no chlorophyll triplet originating from charge recombination between P680+ and Pheo- was observed in the mutant, and there were no flash-induced absorption changes at 820 nm attributable to chlorophyll P680 oxidation. These observations lead us to conclude that CP-47 plays an essential role in the activity of the PSII reaction center.

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Publisher
PNAS
Copyright
Copyright ©2009 by the National Academy of Sciences
ISSN
0027-8424
eISSN
1091-6490
Publisher site
See Article on Publisher Site

Abstract

CP-47 is absent in a genetically engineered mutant of cyanobacterium Synechocystis 6803, in which the psbB gene encoding the chlorophyll-binding photosystem II (PSII) protein CP-47 was interrupted. Another chlorophyll-binding PSII protein, CP-43, is present in the mutant, and functionally inactive PSII-enriched particles can be isolated from mutant thylakoids. We interpret these data as indicating that the PSII core complex of the mutant still assembles in the absence of CP-47. The mutant lacks a 77 K fluorescence emission maximum at 695 nm, suggesting that the PSII reaction center is not functional. The absence of primary photochemistry was indicated by EPR and optical measurements: no chlorophyll triplet originating from charge recombination between P680+ and Pheo- was observed in the mutant, and there were no flash-induced absorption changes at 820 nm attributable to chlorophyll P680 oxidation. These observations lead us to conclude that CP-47 plays an essential role in the activity of the PSII reaction center.

Journal

Proceedings of the National Academy of SciencesPNAS

Published: Dec 1, 1986

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