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Structural and functional dynamics of plant photosystem 11

Anderson, Jan; Chow, Wah S (Fred)

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Given the unique problem of the extremely high potential of the oxidant P680+ that is required to oxidize water to oxygen, the photoinactivation of photosystem II in vivo is inevitable, despite many photoprotective strategies. There is, however, a robustness of photosystem II, which depends partly on the highly dynamic compositional and structural heterogeneity of the cycle between functional and non-functional photosystem II complexes in response to light level. This coordinated regulation...[Show more]

dc.contributor.authorAnderson, Jan
dc.contributor.authorChow, Wah S (Fred)
dc.date.accessioned2015-12-13T22:24:48Z
dc.identifier.issn0962-8436
dc.identifier.urihttp://hdl.handle.net/1885/72914
dc.description.abstractGiven the unique problem of the extremely high potential of the oxidant P680+ that is required to oxidize water to oxygen, the photoinactivation of photosystem II in vivo is inevitable, despite many photoprotective strategies. There is, however, a robustness of photosystem II, which depends partly on the highly dynamic compositional and structural heterogeneity of the cycle between functional and non-functional photosystem II complexes in response to light level. This coordinated regulation involves photon usage (energy utilization in photochemistry) and excess energy dissipation as heat, photoprotection by many molecular strategies, photoinactivation followed by photon damage and ultimately the D1 protein dynamics involved in the photosystem II repair cycle. Compelling, though indirect evidence suggests that the radical pair P680Pheo- in functional PSII should be protected from oxygen. By analogy to the tentative oxygen channel of cytochrome c oxidase, oxygen may be liberated from the two water molecules bound to the catalytic site of the Mn cluster, via a specific pathway to the membrane surface. The function of the proposed oxygen pathway is to prevent O2 from having direct access to P680Pheo- and prevent the generation of singlet oxygen via the triplet-P680 state in functional photosytem IIs. Only when the, as yet unidentified, potential trigger with a fateful first oxidative step destroys oxygen evolution, will the ensuing cascade of structural perturbations of photosystem II destroy the proposed oxygen, water and proton pathways. Then oxygen has direct access to P680+Pheo-, singlet oxygen will be produced and may successively oxidize specific amino acids of the phosphorylated D1 protein of photosystem II dimers that are confined to appressed granal domains, thereby targeting D1 protein for eventual degradation and replacement in non-appressed thylakoid domains.
dc.publisherRoyal Society of London
dc.sourcePhilosophical Transactions of the Royal Society of London Series B
dc.subjectKeywords: membrane protein; oxygen; water; oxidation; photosynthesis; water; binding site; chemistry; conference paper; energy transfer; light; metabolism; oxidation reduction reaction; photosynthesis; photosystem II; protein conformation; Binding Sites; Energy Tra Oxygen pathway; P680+; Photoinactivation; Photosynthesis; Photosystem II; Singlet oxygen
dc.titleStructural and functional dynamics of plant photosystem 11
dc.typeJournal article
local.description.notesImported from ARIES
local.description.refereedYes
local.identifier.citationvolume357
dc.date.issued2002
local.identifier.absfor070303 - Crop and Pasture Biochemistry and Physiology
local.identifier.ariespublicationMigratedxPub3481
local.type.statusPublished Version
local.contributor.affiliationAnderson, Jan, College of Medicine, Biology and Environment, ANU
local.contributor.affiliationChow, Wah S (Fred), College of Medicine, Biology and Environment, ANU
local.description.embargo2037-12-31
local.bibliographicCitation.startpage1421
local.bibliographicCitation.lastpage1430
local.identifier.doi10.1098/rstb.2002.1138
dc.date.updated2015-12-11T08:10:26Z
local.identifier.scopusID2-s2.0-0037195312
CollectionsANU Research Publications

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