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Start Over Subject water-oxidizing complex

1. Reconstitution of water-oxidizing complex in manganese-depleted photosystem 2 preparations with synthetic manganese complexes

Creator:
Chen, G. Y., Han, G. Y., Ling, L., Huang, D. G., Li, S. Q., Khorobrykh, A. A., Zharmukhamedov, S. K., Liu, Q. T., Klimov, V. V., and Kuang, T. Y.
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
manganese complexes, reconstitution, and water-oxidizing complex
Language:
Multiple languages
Description:
Four synthetic manganese complexes in which Mn atoms have different coordination environments and valence states were used to reconstitute water-oxidizing complex (WOC) in Mn-depleted photosystem 2 preparations. Three Mn-complexes restored a significant rate of electron transfer and oxygen evolution except one complex in which Mn atom ligated to the O-atoms within the ligands by covalent linkage. The effect of coordination environment of the Mn-atom within the Mn-complexes on their efficiencies in reconstituting the electron transport and oxygen evolution was analysed. and G. Y. Chen ... [et al.].
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

2. The multiplicity of roles for (bi)carbonate in photosystem II operation in the hypercarbonate-requiring cyanobacterium Arthrospira maxima

Creator:
Ananyev, G., Gates, C., and Dismukes, G. C.
Format:
print, bez média, and svazek
Type:
model:article and TEXT
Subject:
fotosyntéza, photosynthesis, bicarbonate depletion, dissolved inorganic carbon, oxygen-evolving complex, redox tuning, water-oxidizing complex, 2, and 581
Language:
Multiple languages
Description:
Arthrospira maxima is unique among cyanobacteria, growing at alkaline pH (<11) in concentrated (bi)carbonate (1.2 M saturated) and lacking carbonic anhydrases. We investigated dissolved inorganic carbon (DIC) roles within PSII of A. maxima cells oximetrically and fluorometrically, monitoring the light reactions on the donor and acceptor sides of PSII. We developed new methods for removing DIC based on a (bi)carbonate chelator and magnesium for (bi)carbonate ionpairing. We established relative affinities of three sites: the water-oxidizing complex (WOC), non-heme iron/QA-, and solvent-accessible arginines throughout PSII. Full reversibility is achieved but (bi)carbonate uptake requires light. DIC depletion at the non-heme iron site and solvent-accessible arginines greatly reduces the yield of O2 due to O2 uptake, but accelerates the PSII-WOC cycle, specifically the S2-S3 and S3-S0 transitions. DIC removal from the WOC site abolishes water oxidation and appears to influence free energy stabilization of the WOC from a site between CP43-R357 and Ca2+., G. Ananyev, C. Gates, G. C. Dismukes., and Obsahuje bibliografické odkazy
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public