Deletion mutagenesis of the cytochrome b559 protein inactivates the reaction center of photosystem II

In green plant-like photosynthesis, oxygen evolution is catalyzed by a thylakoid membrane-bound protein complex, photosystem II. Cytochrome b559, a protein component of the reaction center of this complex, is absent in a genetically engineered mutant of the cyanobacterium, Synechocystis 6803 [Pakras...

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Bibliographic Details
Published in:The Plant cell 1989-06, Vol.1 (6), p.591-597
Main Authors: Pakrasi, H.B. (Washington University, St. Louis, MO), Diner, B.A, Williams, J.G.K, Arntzen, C.J
Format: Article
Language:English
Subjects:
CHLOROPHYLLE
Chlorophylls
CITOCHROMO B
CLOROFILAS
CYANOPHYTA
CYTOCHROME B
Cytochromes
D2 protein
Fluorescence
FOTOSINTESIS
GENE
GENES
LUMIERE
LUZ
MUTACION
MUTATION
PHOTOSYNTHESE
Photosynthesis
Photosystem II
Plant cells
Plants
PLASTE
PLASTIDIOS
PROPIEDADES OPTICAS
PROPRIETE OPTIQUE
PROTEINAS
PROTEINE
QUINONAS
QUINONE
REDUCCION
REDUCTION
Thylakoids
Wavelengths
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Summary:In green plant-like photosynthesis, oxygen evolution is catalyzed by a thylakoid membrane-bound protein complex, photosystem II. Cytochrome b559, a protein component of the reaction center of this complex, is absent in a genetically engineered mutant of the cyanobacterium, Synechocystis 6803 [Pakrasi, H.B., Williams, J.G.K., and Arntzen, C.J. (1988). EMBO J. 7, 325-332]. In this mutant, the genes psbE and psbF, encoding cytochrome b559, were deleted by targeted mutagenesis. Two other protein components, D1 and D2 of the photosystem II reaction center, are also absent in this mutant. However, two chlorophyll-binding proteins, CP47 and CP43, as well as a manganese-stabilizing extrinsic protein component of photosystem II are stably assembled in the thylakoids of this mutant. Thus, this deletion mutation destabilizes the reaction center of photosystem II only. The mutant also lacks a fluorescence maximum peak at 695 nm (at 77 K) even though the CP47 protein, considered to be the origin of this fluorescence peak, is present in this mutant. We propose that the fluorescence at 695 nm originates from an interaction between the reaction center of photosystem II and CP47. The deletion mutant shows the absence of variable fluorescence at room temperature, indicating that its photosystem II complex is photochemically inactive. Also, photoreduction of QA, the primary acceptor quinone in photosystem II, could not be detected in the mutant. We conclude that cytochrome b559 plays at least an essential structural role in the reaction center of photosystem II
ISSN:1040-4651
1532-298X
DOI:10.1105/tpc.1.6.591