S13/3 Activated q-cycle as a common mechanism for the cytochrome bc1 and cytochrome b6f complexes
نویسندگان
چکیده
منابع مشابه
Cytochrome bc1 complexes of microorganisms.
The cytochrome bc1 complex is the most widely occurring electron transfer complex capable of energy transduction. Cytochrome bc1 complexes are found in the plasma membranes of phylogenetically diverse photosynthetic and respiring bacteria, and in the inner mitochondrial membrane of all eucaryotic cells. In all of these species the bc1 complex transfers electrons from a low-potential quinol to a...
متن کاملThe cytochrome bc1 complex of Rhodobacter capsulatus: ubiquinol oxidation in a dimeric Q-cycle?
We studied the cytochrome bc1 complex (hereafter bc) by flash excitation of Rhodobacter capsulatis chromatophores. The reduction of the high-potential heme b(h), of cytochrome b (at 561 nm) and of cytochromes c (at 552 nm) and the electrochromic absorption transients (at 524 nm) were monitored after the first and second flashes of light, respectively. We kept the ubiquinone pool oxidized in the...
متن کاملRole of the Rieske iron-sulfur protein midpoint potential in the protonmotive Q-cycle mechanism of the cytochrome bc1 complex.
The midpoint potential of the [2Fe-2S] cluster of the Rieske iron-sulfur protein (Em7 = +280 mV) is the primary determinant of the rate of electron transfer from ubiquinol to cytochrome c catalyzed by the cytochrome bc1 complex. As the midpoint potential of the Rieske cluster is lowered by altering the electronic environment surrounding the cluster, the ubiquinol-cytochrome c reductase activity...
متن کاملMultiple Q-cycle bypass reactions at the Qo site of the cytochrome bc1 complex.
The cytochrome (cyt) bc(1) complex is central to energy transduction in many species. Most investigators now accept a modified Q-cycle as the catalytic mechanism of this enzyme. Several thermodynamically favorable side reactions must be minimized for efficient functioning of the Q-cycle. Among these, reduction of oxygen by the Q(o) site semiquinone to produce superoxide is of special pathobiolo...
متن کاملCrystallization of cytochrome bc1 complex.
Complex III (cytochrome bc1 particle; ubiquinol:ferricytochrome c oxidoreductase, EC 1.10.2.2) was purified from beef heart mitochondria by a combination of hydrophobic interaction and affinity chromatography. By washing the complex with detergent on the hydrophobic interaction column, phospholipids were effectively depleted; 7 mol of cardiolipin per mol of cytochrome c1 was retained in the fin...
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ژورنال
عنوان ژورنال: Biochimica et Biophysica Acta (BBA) - Bioenergetics
سال: 2008
ISSN: 0005-2728
DOI: 10.1016/j.bbabio.2008.05.347