The Experts below are selected from a list of 105 Experts worldwide ranked by ideXlab platform
John D Helmann - One of the best experts on this subject based on the ideXlab platform.
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the ohrr repressor senses organic hydroperoxides by reversible formation of a cysteine Sulfenic Acid Derivative
Proceedings of the National Academy of Sciences of the United States of America, 2002Co-Authors: Mayuree Fuangthong, John D HelmannAbstract:Reactive oxygen species induce the expression of detoxification and repair genes critical for life in an aerobic environment. Bacterial factors that sense reactive oxygen species use either thiol-disulfide exchange reactions (OxyR, RsrA) or redox labile 2Fe–2S clusters (SoxR). We demonstrate that the reduced form of Bacillus subtilis OhrR binds cooperatively to two adjacent inverted repeat sequences in the ohrA control region and thereby represses transcription. In the presence of organic hydroperoxides, OhrR is inactivated by the reversible oxidation of a single conserved cysteine residue to the corresponding cysteine-Sulfenic Acid, and perhaps to higher oxidation states.
Tsuyoshi Inoue - One of the best experts on this subject based on the ideXlab platform.
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Oxidation of archaeal peroxiredoxin involves a hypervalent sulfur intermediate
Proceedings of the National Academy of Sciences of the United States of America, 2008Co-Authors: Tsutomu Nakamura, Takahiko Yamamoto, Manabu Abe, Hiroyoshi Matsumura, Yoshihisa Hagihara, Tadashi Goto, Takafumi Yamaguchi, Tsuyoshi InoueAbstract:The oxidation of thiol groups in proteins is a common event in biochemical processes involving disulfide bond formation and in response to an increased level of reactive oxygen species. It has been widely accepted that the oxidation of a cysteine side chain is initiated by the formation of cysteine Sulfenic Acid (Cys-SOH). Here, we demonstrate a mechanism of thiol oxidation through a hypervalent sulfur intermediate by presenting crystallographic evidence from an archaeal peroxiredoxin (Prx), the thioredoxin peroxidase from Aeropyrum pernix K1 (ApTPx). The reaction of Prx, which is the reduction of a peroxide, depends on the redox active cysteine side chains. Oxidation by hydrogen peroxide converted the active site peroxidatic Cys-50 of ApTPx to a cysteine Sulfenic Acid Derivative, followed by further oxidation to cysteine sulfinic and sulfonic Acids. The crystal structure of the cysteine Sulfenic Acid Derivative was refined to 1.77 A resolution with R(cryst) and R(free) values of 18.8% and 22.0%, respectively. The refined structure, together with quantum chemical calculations, revealed that the Sulfenic Acid Derivative is a type of sulfurane, a hypervalent sulfur compound, and that the S(gamma) atom is covalently linked to the N(delta1) atom of the neighboring His-42. The reaction mechanism is revealed by the hydrogen bond network around the peroxidatic cysteine and the motion of the flexible loop covering the active site and by quantum chemical calculations. This study provides evidence that a hypervalent sulfur compound occupies an important position in biochemical processes.
Mayuree Fuangthong - One of the best experts on this subject based on the ideXlab platform.
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the ohrr repressor senses organic hydroperoxides by reversible formation of a cysteine Sulfenic Acid Derivative
Proceedings of the National Academy of Sciences of the United States of America, 2002Co-Authors: Mayuree Fuangthong, John D HelmannAbstract:Reactive oxygen species induce the expression of detoxification and repair genes critical for life in an aerobic environment. Bacterial factors that sense reactive oxygen species use either thiol-disulfide exchange reactions (OxyR, RsrA) or redox labile 2Fe–2S clusters (SoxR). We demonstrate that the reduced form of Bacillus subtilis OhrR binds cooperatively to two adjacent inverted repeat sequences in the ohrA control region and thereby represses transcription. In the presence of organic hydroperoxides, OhrR is inactivated by the reversible oxidation of a single conserved cysteine residue to the corresponding cysteine-Sulfenic Acid, and perhaps to higher oxidation states.
Tsutomu Nakamura - One of the best experts on this subject based on the ideXlab platform.
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Oxidation of archaeal peroxiredoxin involves a hypervalent sulfur intermediate
Proceedings of the National Academy of Sciences of the United States of America, 2008Co-Authors: Tsutomu Nakamura, Takahiko Yamamoto, Manabu Abe, Hiroyoshi Matsumura, Yoshihisa Hagihara, Tadashi Goto, Takafumi Yamaguchi, Tsuyoshi InoueAbstract:The oxidation of thiol groups in proteins is a common event in biochemical processes involving disulfide bond formation and in response to an increased level of reactive oxygen species. It has been widely accepted that the oxidation of a cysteine side chain is initiated by the formation of cysteine Sulfenic Acid (Cys-SOH). Here, we demonstrate a mechanism of thiol oxidation through a hypervalent sulfur intermediate by presenting crystallographic evidence from an archaeal peroxiredoxin (Prx), the thioredoxin peroxidase from Aeropyrum pernix K1 (ApTPx). The reaction of Prx, which is the reduction of a peroxide, depends on the redox active cysteine side chains. Oxidation by hydrogen peroxide converted the active site peroxidatic Cys-50 of ApTPx to a cysteine Sulfenic Acid Derivative, followed by further oxidation to cysteine sulfinic and sulfonic Acids. The crystal structure of the cysteine Sulfenic Acid Derivative was refined to 1.77 A resolution with R(cryst) and R(free) values of 18.8% and 22.0%, respectively. The refined structure, together with quantum chemical calculations, revealed that the Sulfenic Acid Derivative is a type of sulfurane, a hypervalent sulfur compound, and that the S(gamma) atom is covalently linked to the N(delta1) atom of the neighboring His-42. The reaction mechanism is revealed by the hydrogen bond network around the peroxidatic cysteine and the motion of the flexible loop covering the active site and by quantum chemical calculations. This study provides evidence that a hypervalent sulfur compound occupies an important position in biochemical processes.
Takahiko Yamamoto - One of the best experts on this subject based on the ideXlab platform.
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Oxidation of archaeal peroxiredoxin involves a hypervalent sulfur intermediate
Proceedings of the National Academy of Sciences of the United States of America, 2008Co-Authors: Tsutomu Nakamura, Takahiko Yamamoto, Manabu Abe, Hiroyoshi Matsumura, Yoshihisa Hagihara, Tadashi Goto, Takafumi Yamaguchi, Tsuyoshi InoueAbstract:The oxidation of thiol groups in proteins is a common event in biochemical processes involving disulfide bond formation and in response to an increased level of reactive oxygen species. It has been widely accepted that the oxidation of a cysteine side chain is initiated by the formation of cysteine Sulfenic Acid (Cys-SOH). Here, we demonstrate a mechanism of thiol oxidation through a hypervalent sulfur intermediate by presenting crystallographic evidence from an archaeal peroxiredoxin (Prx), the thioredoxin peroxidase from Aeropyrum pernix K1 (ApTPx). The reaction of Prx, which is the reduction of a peroxide, depends on the redox active cysteine side chains. Oxidation by hydrogen peroxide converted the active site peroxidatic Cys-50 of ApTPx to a cysteine Sulfenic Acid Derivative, followed by further oxidation to cysteine sulfinic and sulfonic Acids. The crystal structure of the cysteine Sulfenic Acid Derivative was refined to 1.77 A resolution with R(cryst) and R(free) values of 18.8% and 22.0%, respectively. The refined structure, together with quantum chemical calculations, revealed that the Sulfenic Acid Derivative is a type of sulfurane, a hypervalent sulfur compound, and that the S(gamma) atom is covalently linked to the N(delta1) atom of the neighboring His-42. The reaction mechanism is revealed by the hydrogen bond network around the peroxidatic cysteine and the motion of the flexible loop covering the active site and by quantum chemical calculations. This study provides evidence that a hypervalent sulfur compound occupies an important position in biochemical processes.
