Studies on structure and function of photosystem II in oxygenic photosynthesis: Stoichiometry of cytochromeb-559 inSynechocystis sp. PCC 6803

Cytochromeb-559 is an integral protein of the photosystem II (PSII) reaction center from both plants and cyanobacteria. Cytochromeb-559 has the unique structure of a heme crosslinked α- and β-subunit heterodimer. The stoichiometry of cytochromeb-559 (one or two copies) per the PSII reaction center h...

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Bibliographic Details
Published in:Journal of plant biology = Singmul Hakhoe chi 1997-06, Vol.40 (2), p.125-131
Main Authors: Cha, Hyeon Cheol, Tae, Gun-Sik
Format: Article
Language:English
Subjects:
Chlorophyll
Cyanobacteria
Heme
Photosynthesis
Photosystem II
Stoichiometry
Structure-function relationships
Thylakoids
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Summary:Cytochromeb-559 is an integral protein of the photosystem II (PSII) reaction center from both plants and cyanobacteria. Cytochromeb-559 has the unique structure of a heme crosslinked α- and β-subunit heterodimer. The stoichiometry of cytochromeb-559 (one or two copies) per the PSII reaction center has been the subject of controversy and the molar ratio of the heme group to the special chlorophyll P-680 has a number of significant implications on our understanding of the functional role of cytochromeb-559, the mechanism of electron donation in PSII, and the stoichiometry of the other redox-active reaction center components. In order to determine the number of the cytochromeb-559 heme in the PSII reaction center ofSynechocystis sp. PCC 6803, the α- and β-subunits are covalently linked by use of the molecular genetic techniques. The resultingpsbEF fusion mutant was able to grow photoautotrophically, implying that the PSII complexes are assembled and functional in thylakoids. This result supports the fact that there are two set of cytochromeb-559 in the PSII reaction center ofSynechocystis sp. PCC 6803.
ISSN:1226-9239
1867-0725
DOI:10.1007/BF03030245