Spectroscopic Investigation of Cysteamine Dioxygenase.
Spectroscopic Investigation of Cysteamine Dioxygenase.
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DOI：
10.1021/acs.biochem.0c00267
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发表时间：
2020-07-07
期刊：
影响因子：
2.9
通讯作者：
Brunold TC
中科院分区：
文献类型：
--
作者：
Fernandez RL;Dillon SL;Stipanuk MH;Fox BG;Brunold TC
硫醇双加氧酶是单核非血红素 FeII 依赖性金属酶，可启动含硫醇底物氧化分解为其各自的亚磺酸盐。半胱氨酸双加氧酶 (CDO) 是特征最明确的哺乳动物硫醇双加氧酶，包含 3-组氨酸 (3-His) 配位环境，而不是大多数单核非血红素 FeII 酶中常见的 2-His-1- 羧酸盐面部三联体。在细菌硫醇双加氧酶 3-巯基丙酸双加氧酶 (MDO) 中发现了类似的 3-His 活性位点，该酶将 3-巯基丙酸 (3-MPA) 转化为 3-亚磺基丙酸，作为细菌硫代谢途径的一部分。在本研究中，我们通过使用光谱方法研究了第三种非血红素 FeII 依赖性硫醇双加氧酶半胱胺双加氧酶 (ADO) 的活性位点几何和电子结构。尽管之前已根据序列比对和定点突变研究发现了 3-His 面部三联体，但目前对 ADO 的活性位点环境知之甚少。我们的磁圆二色性和电子顺磁共振数据提供了令人信服的证据，证明 ADO 具有 3-组氨酸面部三联体，如 CDO 和 MDO。尽管存在相似的配位环境，但与底物和各种底物类似物一起孵育的 ADO 获得的光谱结果与其他 FeII 依赖性硫醇双加氧酶获得的光谱结果不同。这一发现表明，ADO 的次级配位层与 CDO 和 MDO 的次级配位层不同，证明了次级球残基在决定底物特异性方面发挥着重要作用。
Thiol dioxygenases are mononuclear non-heme FeII-dependent metalloenzymes that initiate the oxidative catabolism of thiol-containing substrates to their respective sulfinates. Cysteine dioxygenase (CDO), the best characterized mammalian thiol dioxygenase, contains a 3-histidine (3-His) coordination environment rather than the 2-His-1-carboxylate facial triad seen in most mononuclear non-heme FeII enzymes. A similar 3-His active site is found in the bacterial thiol dioxygenase 3-mercaptopropionate dioxygenase (MDO), which converts 3-mercaptopropionate (3-MPA) into 3-sulfinopropionic acid as part of bacterial sulfur metabolism pathway. In the present study, we have investigated the active site geometric and electronic structures of a third non-heme FeII-dependent thiol dioxygenase, cysteamine dioxygenase (ADO), by using a spectroscopic approach. Although a 3-His facial triad had previously been implicated on the basis of sequence alignment and site-directed mutagenesis studies, little is currently known about the active site environment of ADO. Our magnetic circular dichroism and electron paramagnetic resonance data provide compelling evidence that ADO features a 3-histidine facial triad, like CDO and MDO. Despite this similar coordination environment, spectroscopic results obtained for ADO incubated with substrate and various substrate analogues are distinct from those obtained for the other FeII-dependent thiol dioxygenases. This finding suggests that the secondary coordination sphere of ADO is distinct from those of CDO and MDO, demonstrating the significant role that secondary sphere residues play in dictating substrate specificity.
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影响因子：
2.9
作者：
Diebold, Adrienne R.;Neidig, Michael L.;Moran, Graham R.;Straganz, Grit D.;Solomon, Edward I.
通讯作者：
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影响因子：
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作者：
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通讯作者：
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影响因子：
48
作者：
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通讯作者：
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影响因子：
2.9
作者：
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通讯作者：
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影响因子：
3.2
作者：
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通讯作者：
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