Arsenic(III) species inhibit oxidative protein folding in vitro.
Arsenic(III) species inhibit oxidative protein folding in vitro.
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DOI：
10.1021/bi801988x
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发表时间：
2009-01-20
期刊：
影响因子：
2.9
通讯作者：
Thorpe, Colin
中科院分区：
文献类型：
--
作者：
Ramadan, Danny;Rancy, Pumtiwitt C.;Nagarkar, Radhika P.;Schneider, Joel P.;Thorpe, Colin
三氧化二砷在治疗急性早幼粒细胞白血病中的成功重新引起了人们对As（III）物质的细胞靶点的兴趣。砷剂的作用通常归因于它们能够结合预折叠蛋白质中的邻位硫醇或硫醇-硒醇，从而损害细胞功能。目前的研究表明，更多的多效性，砷剂的生物效应的贡献。As（III）物种通过与未折叠还原蛋白的半胱氨酸残基的亲合配位，可以损害蛋白质折叠途径。三个代表性的作为（三）化合物（亚砷酸; monomethylarsenous酸，MMA;和芳基砷，PSAO）已被测试与三个减少分泌蛋白（溶菌酶，核糖核酸酶A和核黄素结合蛋白，RfBP）。使用吸光度，荧光和前稳态的方法，我们表明，砷紧密结合低微摩尔浓度的这些未折叠的蛋白质与化学计量的1 As（III）每2硫醇为MMA和PSAO和1 As（III）的每3硫醇与亚砷酸盐。即使在存在5 mM还原型谷胱甘肽（As（III）物质的竞争配体）的情况下，10 μM砷也会强烈破坏RfBP的氧化折叠。MMA使用还原的RNA酶催化淀粉样单分散原纤维的形成。这些体外数据表明，As（III）物种可以减缓，甚至脱轨，蛋白质折叠途径。在体内，As（III）物质与未折叠的含半胱氨酸蛋白质结合的倾向可能会导致氧化和蛋白质折叠应激，这些应激是细胞对砷暴露反应的突出特征。
The success of arsenic trioxide in the treatment of acute promyelocytic leukemia has renewed interest in the cellular targets of As(III) species. The effects of arsenicals are usually attributed to their ability to bind vicinal thiols or thiol-selenols in pre-folded proteins thereby compromising cellular function. The present studies suggest an additional, more pleiotropic, contribution to the biological effects of arsenicals. As(III) species, by avid coordination to the cysteine residues of unfolded reduced proteins, can compromise protein folding pathways. Three representative As(III) compounds (arsenite; monomethylarsenous acid, MMA; and an aryl arsenical, PSAO) have been tested with three reduced secreted proteins (lysozyme, ribonuclease A and riboflavin binding protein, RfBP). Using absorbance, fluorescence and pre-steady state methods, we show that arsenicals bind tightly to low micromolar concentrations of these unfolded proteins with stoichiometries of 1 As(III) per 2 thiols for MMA and PSAO and 1 As(III) for every 3 thiols with arsenite. Arsenicals, at 10 μM, strongly disrupt the oxidative folding of RfBP even in the presence of 5 mM reduced glutathione, a competing ligand for As(III) species. MMA catalyzes the formation of amyloid-like monodisperse fibrils using reduced RNase. These in vitro data show that As(III) species can slow, or even derail, protein folding pathways. In vivo, the propensity of As(III) species to bind to unfolded cysteine-containing proteins may contribute to oxidative and protein folding stresses that are prominent features of the cellular response to arsenic exposure.
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影响因子：
15
作者：
Cline, DJ;Thorpe, C;Schneider, JP
通讯作者：
Schneider, JP
影响因子：
2.9
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2.9
作者：
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Thorpe, C