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Murata N.,Japan National Institute for Basic Biology | Allakhverdiev S.I.,RAS Institute of Basic Biological Problems | Nishiyama Y.,Saitama University
Biochimica et Biophysica Acta - Bioenergetics | Year: 2012

Photoinhibition of photosystem II (PSII) occurs when the rate of light-induced inactivation (photodamage) of PSII exceeds the rate of repair of the photodamaged PSII. For the quantitative analysis of the mechanism of photoinhibition of PSII, it is essential to monitor the rate of photodamage and the rate of repair separately and, also, to examine the respective effects of various perturbations on the two processes. This strategy has allowed the re-evaluation of the results of previous studies of photoinhibition and has provided insight into the roles of factors and mechanisms that protect PSII from photoinhibition, such as catalases and peroxidases, which are efficient scavengers of H2O2; α-tocopherol, which is an efficient scavenger of singlet oxygen; non-photochemical quenching, which dissipates excess light energy that has been absorbed by PSII; and the cyclic and non-cyclic transport of electrons. Early studies of photoinhibition suggested that all of these factors and mechanisms protect PSII against photodamage. However, re-evaluation by the strategy mentioned above has indicated that, rather than protecting PSII from photodamage, they stimulate protein synthesis, with resultant repair of PSII and mitigation of photoinhibition. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial. © 2011 Elsevier B.V. All rights reserved. Source


Soltamov V.A.,RAS Ioffe Physical - Technical Institute | Soltamova A.A.,RAS Ioffe Physical - Technical Institute | Baranov P.G.,RAS Ioffe Physical - Technical Institute | Proskuryakov I.I.,RAS Institute of Basic Biological Problems
Physical Review Letters | Year: 2012

We report the realization of the optically induced inverse population of the ground-state spin sublevels of the silicon vacancies (V Si) in silicon carbide (SiC) at room temperature. The data show that the probed silicon vacancy spin ensemble can be prepared in a coherent superposition of the spin states. Rabi nutations persist for more than 80μs. Two opposite schemes of the optical alignment of the populations between the ground-state spin sublevels of the silicon vacancy upon illumination with unpolarized light are realized in 4H- and 6H-SiC at room temperature. These altogether make the silicon vacancy in SiC a very favorable defect for spintronics, quantum information processing, and magnetometry. © 2012 American Physical Society. Source


Najafpour M.M.,Institute for Advanced Studies in Basic Sciences | Allakhverdiev S.I.,RAS Institute of Basic Biological Problems
International Journal of Hydrogen Energy | Year: 2012

For hydrogen production by water splitting, the water oxidation half reaction is overwhelmingly rate limiting and needs high over-voltage (∼1 V), which results in low conversion efficiencies when working at current densities required. At this high voltage, other chemicals will be also oxidized and this would be environmentally unacceptable for large-scale H 2 production. In past few years, there has been a tremendous surge in research on the synthesis of various metal compounds aimed at the simulating water oxidizing complex of Photosystem II. Particular attention has been given to the manganese compounds not only because manganese has been used by Nature to oxidize water but also because manganese is cheap and environmentally friendly. In this review, we focus on manganese compounds as functional models of the water oxidizing complex of Photosystem II for hydrogen production via water splitting. © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved. Source


Wiechen M.,Monash University | Najafpour M.M.,Institute for Advanced Studies in Basic Sciences | Allakhverdiev S.I.,RAS Institute of Basic Biological Problems | Spiccia L.,Monash University
Energy and Environmental Science | Year: 2014

The Oxygen Evolving Complex (OEC) in photosystem II, a cluster that contains four manganese and one calcium ions bridged by five oxygen atoms in a distorted chair like arrangement, carries out the biological oxidation of water during photosynthesis. Since this is the only cluster established in biological water oxidation catalysis, efforts have been made to develop synthetic systems that mimic its structure, properties and water oxidation activity. This perspective provides a brief overview of the current structural and mechanistic understanding of the OEC in photosystem II. It then compares the structural features of this complex with those of manganese oxide water oxidation catalysts and discusses structure-function relationships that inform the development of new catalysts. The identified features should be considered when endeavouring to design manganese oxide, and other metal oxide, catalysts with optimal activity that can ultimately be integrated into photo-electrochemical devices to achieve solar water-splitting. © The Royal Society of Chemistry 2014. Source


Ivanov B.N.,RAS Institute of Basic Biological Problems
Biochemistry (Moscow) | Year: 2014

Experimental data concerning the role of ascorbic acid in both the maintenance of photosynthesis and in the protection of the photosynthetic apparatus against reactive oxygen species and photoinhibition are reviewed. The function of ascorbic acid as an electron donor in the "Krasnovsky reaction", as well as its physiological role as a donor to components of the photosynthetic electron transport chain, which was first studied by A. A. Krasnovsky in the 1980s, is discussed. Data on the content and transport of ascorbic acid in plant cells and chloroplasts are presented. © 2014 Pleiades Publishing, Ltd. Source

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