Stimulation of oxygen evolution in photosystem II by copper(II) ions.

نویسندگان

  • Kvetoslava Burda
  • Jerzy Kruk
  • Kazimierz Strzalka
  • Georg H Schmid
چکیده

We have found that copper(II) ions at about equimolar Cu2+/photosystem II (PS II) reaction center proportions stimulate oxygen evolution nearly twofold. This high affinity Cu-binding site is different from the binding sites of Mn and Ca ions. The analysis of the Cu2+ content in PS II preparations isolated from wild-type tobacco and a tobacco mutant deficient in light-harvesting complex suggests that Cu2+ may be a native component of PS II and may take part in the oxygen evolution process. At higher concentrations, Cu2+ ions inhibit oxygen evolution and quench fluorescence.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Inhibition of oxygen evolution in Photosystem II by Cu(II) ions is associated with oxidation of cytochrome b559.

We have found that elevated copper concentrations, apart from the inhibition of oxygen evolution, changed the initial states distribution of the oxygen-evolving complex. Already at low concentrations, copper ions oxidized the low-potential form of cytochrome b (559) and also its high-potential form at higher concentrations at which fluorescence quenching was observed. We suggest that the primar...

متن کامل

Molecular Mechanism of Copper Toxicity on Electron Transfer through Photosystem Ii

Photosystem II (PSII) is the site of action of a large number of commercial herbicides and it is the site, where photoinhibition appears when plants are exposed to high light intensities. It is known that manganese, calcium and chloride ions are essential for optimal electron flow within PSII. Recently we have found that at very low concentrations (1-1.5 Cu 2+ / reaction center) copper improves...

متن کامل

Bicarbonte stimulation, of oxygen evolution, ferricyanide reduction and photoinactivation using isolated chloroplasts

Dependence of Hill reaction (ferricyanide reduction) by isolated (broken) chloroplasts on bicarbonate ion increases with time of illumination (upto 4 min) in HCC>3~ free reaction mixture. The stimulation caused by HCOs" is independent of light intensity down to very low intensities indicating an involvement of this ion in early photochemical events of photosystem II. Oxygen evolution was found ...

متن کامل

Copper effect on the protein composition of photosystem II

We provide data from in vitro experiment on the polypeptide composition, photosynthetic electron transport and oxygen evolution activity of intact photosystem II (PSII) preparations under Cu(II) toxicity conditions. Low Cu(II) concentrations (Cu(II) per PSII reaction centre unit < 230) that caused around 50% inhibition of variable chlorophyll a fluorescence and oxygen evolution activity did not...

متن کامل

Elimination of Copper (II) Ions from Aqueous Solution by the using of gamma alumina nanoparticles

heavy metals, as gamma alumina nanoparticles pollutants, in water resources. Therefore, the purpose of this paper was to evaluate the removal of copper (II) ions from aqueous solutions using gamma alumina nanoparticles as a adsorbent. Batch adsorption studies carried out to study various parameters included contact time, initial concentration of copper (II) ions, pH, and gamma alumina nanoparti...

متن کامل

ذخیره در منابع من

ذخیره در منابع من قبلا به منابع من ذحیره شده

{@ msg_add @}


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Zeitschrift fur Naturforschung. C, Journal of biosciences

دوره 57 9-10  شماره 

صفحات  -

تاریخ انتشار 2002