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Coordination Of Selenium To Molybdenum In Formate Dehydrogenase H From Escherichia Coli, Vadim Gladyshev, Sergei V. Khangulov, Milton J. Axley, Thressa A. Stadtman
Coordination Of Selenium To Molybdenum In Formate Dehydrogenase H From Escherichia Coli, Vadim Gladyshev, Sergei V. Khangulov, Milton J. Axley, Thressa A. Stadtman
Vadim Gladyshev Publications
Formate dehydrogenase H from Escherichia col contains multiple redox centers, which include a molybdopterin cofactor, an iron-sulfur center, and a selenocysteine residue (SeCys-140 in the polypeptide chain) that is essential for catalytic activity. Here we show that addition of formate to the native enzyme induces a signal typical of Mo(V) species. This signal is detected by electron pm etc resonance (EPR) spectroscopy. Substitution of 77Se for natural isotope abundance Se leads to transformation of this signal, indicating a direct coordination of Se with Mo. Mutant enzyme with cysteine substituted at position 140 for the selenocysteine residue has decreased catalytic activity …
Nicotinic Acid Hydroxylase From Clostridium Barkeri: Electron Paramagnetic Resonance Studies Show That Selenium Is Coordinated With Molybdenum In The Catalytically Active Selenium-Dependent Enzymenicotinic Acid Hydroxylase From Clostridium Barkeri: Electron Paramagnetic Resonance Studies Show That Selenium Is Coordinated With Molybdenum In The Catalytically Active Selenium-Dependent Enzyme, Vadim Gladyshev, Sergei V. Khangulov, Thressa C. Stadtman
Nicotinic Acid Hydroxylase From Clostridium Barkeri: Electron Paramagnetic Resonance Studies Show That Selenium Is Coordinated With Molybdenum In The Catalytically Active Selenium-Dependent Enzymenicotinic Acid Hydroxylase From Clostridium Barkeri: Electron Paramagnetic Resonance Studies Show That Selenium Is Coordinated With Molybdenum In The Catalytically Active Selenium-Dependent Enzyme, Vadim Gladyshev, Sergei V. Khangulov, Thressa C. Stadtman
Vadim Gladyshev Publications
Nicotinic acid hydroxylase from Clostidum barkeri contains selenium in an unidentified form that is dissociated as a low molecular weight compound upon denaturation of the enzyme. Other cofactors of this enzyme are molybdopterin, FAD, and iron-sulfur clusters. In the current study, we show that the enzyme, as isolated, exhibits a stable Mo(V) electron paramagnetic resonance (EPR) sal ("resting" signal) and that this signal is correlated with the selenium content and nicotinate hydroxylase activity of the enzyme. Substitution of77Se for normal selenium isotope abundance results in splitting of the Mo(V) EPR signal of the native protein without affecting the iron signals …