کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2826664 1162257 2006 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Understanding the cytochrome bc complexes by what they don't do. The Q-cycle at 30
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک دانش گیاه شناسی
پیش نمایش صفحه اول مقاله
Understanding the cytochrome bc complexes by what they don't do. The Q-cycle at 30
چکیده انگلیسی

The cytochrome (cyt) bc1, b6f and related complexes are central components of the respiratory and photosynthetic electron transport chains. These complexes carry out an extraordinary sequence of electron and proton transfer reactions that conserve redox energy in the form of a trans-membrane proton motive force for use in synthesizing ATP and other processes. Thirty years ago, Peter Mitchell proposed a general turnover mechanism for these complexes, which he called the Q-cycle. Since that time, many opposing schemes have challenged the Q-cycle but, with the accumulation of large amounts of biochemical, kinetic, thermodynamic and high-resolution structural data, the Q-cycle has triumphed as the accepted model, although some of the intermediate steps are poorly understood and still controversial. One of the major research questions concerning the cyt bc1 and b6f complexes is how these enzymes suppress deleterious and dissipative side reactions. In particular, most Q-cycle models involve reactive semiquinone radical intermediates that can reduce O2 to superoxide and lead to cellular oxidative stress. Current models to explain the avoidance of side reactions involve unprecedented or unusual enzyme mechanisms, the testing of which will involve new theoretical and experimental approaches.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: - Volume 11, Issue 1, January 2006, Pages 46–55
نویسندگان
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