Analysis of Dipolar and Exchange Interactions between Manganese and Tyrosine Z in the S2YZ•State of Acetate-Inhibited Photosystem II via EPR Spectral Simulations at X- and Q-Bands

1998 ◽  
Vol 102 (42) ◽  
pp. 8327-8335 ◽  
Author(s):  
K. V. Lakshmi ◽  
Sandra S. Eaton ◽  
Gareth R. Eaton ◽  
Harry A. Frank ◽  
Gary W. Brudvig
Keyword(s):  
Photosystem Ii ◽  
Exchange Interactions ◽  
Tyrosine Z ◽  
Spectral Simulations

The EPR Spectrum of Tyrosine Z•and Its Decay Kinetics in O2-Evolving Photosystem II Preparations†

Biochemistry ◽  
2008 ◽  
Vol 47 (24) ◽  
pp. 6292-6300 ◽  
Author(s):  
Nikolaos Ioannidis ◽  
Georgia Zahariou ◽  
Vasili Petrouleas
Keyword(s):  
Photosystem Ii ◽  
Decay Kinetics ◽  
Epr Spectrum ◽  
Tyrosine Z

245 GHz High-Field EPR Study of Tyrosine-D° and Tyrosine-Z° in Mutants of Photosystem II†

Biochemistry ◽  
1996 ◽  
Vol 35 (3) ◽  
pp. 679-684 ◽  
Author(s):  
Sun Un ◽  
Xiao-Song Tang ◽  
Bruce A. Diner
Keyword(s):  
Photosystem Ii ◽  
High Field ◽  
Tyrosine Z ◽  
Tyrosine D

scholarly journals Water oxidation chemistry of photosystem II

2002 ◽  
Vol 357 (1426) ◽  
pp. 1395-1405 ◽  
Author(s):  
John S. Vrettos ◽  
Gary W. Brudvig
Keyword(s):  
Photosystem Ii ◽  
Water Oxidation ◽  
Ion Selectivity ◽  
Bound Water ◽  
Nucleophilic Attack ◽  
Manganese Cluster ◽  
Bond Forming ◽  
Proton Coupled Electron Transfer ◽  
Tyrosine Z ◽  
Oxidation Chemistry

The O 2 –evolving complex of photosystem II catalyses the light–driven four–electron oxidation of water to dioxygen in photosynthesis. In this article, the steps leading to photosynthetic O 2 evolution are discussed. Emphasis is given to the proton–coupled electron–transfer steps involved in oxidation of the manganese cluster by oxidized tyrosine Z (Y Z ), the function of Ca 2+ and the mechanism by which water is activated for formation of an O–O bond. Based on a consideration of the biophysical studies of photosystem II and inorganic manganese model chemistry, a mechanism for photosynthetic O 2 evolution is presented in which the O–O bond–forming step occurs via nucleophilic attack on an electron–deficient Mn V =O species by a calcium–bound water molecule. The proposed mechanism includes specific roles for the tetranuclear manganese cluster, calcium, chloride, Y Z and His190 of the D1 polypeptide. Recent studies of the ion selectivity of the calcium site in the O 2 –evolving complex and of a functional inorganic manganese model system that test key aspects of this mechanism are also discussed.

Tyrosine-Z in Oxygen-Evolving Photosystem II:  A Hydrogen-Bonded Tyrosinate†

Biochemistry ◽  
1999 ◽  
Vol 38 (4) ◽  
pp. 1258-1267 ◽  
Author(s):  
Michael Haumann ◽  
Armen Mulkidjanian ◽  
Wolfgang Junge
Keyword(s):  
Photosystem Ii ◽  
Tyrosine Z ◽  
Oxygen Evolving ◽  
Hydrogen Bonded
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