Redox thermodynamics of high-spin and low-spin forms of chlorite dismutases with diverse subunit and oligomeric structures.
Redox thermodynamics of high-spin and low-spin forms of chlorite dismutases with diverse subunit and oligomeric structures.
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DOI：
10.1021/bi3013033
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发表时间：
2012-11-27
期刊：
影响因子：
2.9
通讯作者：
Obinger C
中科院分区：
文献类型：
--
作者：
Hofbauer S;Bellei M;Sündermann A;Pirker KF;Hagmüller A;Mlynek G;Kostan J;Daims H;Furtmüller PG;Djinović-Carugo K;Oostenbrink C;Battistuzzi G;Obinger C
亚氯酸盐歧化酶(Clds)是一种含亚铁血红素b的氧化还原酶，能将亚氯酸盐转化为氯和氧气。本工作通过光谱电化学实验，测定了硝酸杆菌(Nitrobacter winogradskyi，NwCld)和假丝酵母(Candidatus“Nitrospira defluvii”，NdCld)酶的铁高自旋形式和六配位低自旋氰化物加合物的单电子还原热力学。这些蛋白质属于两个不同的系统发育谱系，它们在亚基(分别为21.5 kDa和26 kDa)和寡聚体(分别为二聚体和五聚体)结构上不同，但具有相似的绿泥石降解活性。在pH 7.0，25°C时，NwCd的游离态和氰基结合蛋白的E°‘值分别为−119 mV和−397 mV，NdCd的E°’值为−113 mV和−404 mV。变温光谱电化学实验表明，这两种蛋白质的氧化态都是热稳定性的。分子动力学模拟表明，蛋白质结构的变化可以忽略不计，而溶剂重组是氧化还原反应过程中熵增加的主要原因。根据两个ClD的已知结构和所提出的反应机理，讨论了所获得的数据。
Chlorite dismutases (Clds) are heme b-containing oxidoreductases that convert chlorite to chloride and dioxygen. In this work, the thermodynamics of the one-electron reduction of the ferric high-spin forms and of the six-coordinate low-spin cyanide adducts of the enzymes from Nitrobacter winogradskyi (NwCld) and Candidatus “Nitrospira defluvii” (NdCld) were determined through spectroelectrochemical experiments. These proteins belong to two phylogenetically separated lineages that differ in subunit (21.5 and 26 kDa, respectively) and oligomeric (dimeric and pentameric, respectively) structure but exhibit similar chlorite degradation activity. The E°′ values for free and cyanide-bound proteins were determined to be −119 and −397 mV for NwCld and −113 and −404 mV for NdCld, respectively (pH 7.0, 25 °C). Variable-temperature spectroelectrochemical experiments revealed that the oxidized state of both proteins is enthalpically stabilized. Molecular dynamics simulations suggest that changes in the protein structure are negligible, whereas solvent reorganization is mainly responsible for the increase in entropy during the redox reaction. Obtained data are discussed with respect to the known structures of the two Clds and the proposed reaction mechanism.
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影响因子：
3.9
作者：
Furtmüller, PG;Arnhold, J;Obinger, C
通讯作者：
Obinger, C
影响因子：
15
作者：
Battistuzzi, G;Borsari, M;Sola, M
通讯作者：
Sola, M
DOI：
10.1046/j.1432-1033.2002.03208.x
发表时间：
2002-10-01
期刊：
EUROPEAN JOURNAL OF BIOCHEMISTRY
影响因子：
--
作者：
Hagedoorn, PL;de Geus, DC;Hagen, WR
通讯作者：
Hagen, WR
影响因子：
3.9
作者：
Battistuzzi, Gianantonio;Bellei, Marzia;Obinger, Christian
通讯作者：
Obinger, Christian
影响因子：
3
作者：
Battistuzzi, Gianantonio;Bellei, Marzia;Sola, Marco
通讯作者：
Sola, Marco