Oxidative stress-dependent structural and functional switching of a human 2-Cys peroxiredoxin Isotype II that enhances HeLa cell resistance to H2O2-induced cell death
Oxidative stress-dependent structural and functional switching of a human 2-Cys peroxiredoxin Isotype II that enhances HeLa cell resistance to H2O2-induced cell death
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DOI：
10.1074/jbc.m505362200
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发表时间：
2005-08-05
影响因子：
4.8
通讯作者：
Lee, SY
中科院分区：
文献类型：
--
作者：
Moon, JC;Hah, YS;Lee, SY
尽管 2-Cys 过氧化物氧还蛋白 (Prxs) 的生化特性已被广泛研究，但它们在高等真核细胞中的真正生理功能仍然不清楚，当然值得进一步研究。在这里，我们证明了人（h）PrxII（人2-Cys Prx的胞质同种型）具有过氧化物酶和分子伴侣的双重功能，并且这些不同的功能与其采用不同的蛋白质结构密切相关。暴露于氧化应激后，hPrxII 呈现出具有高效伴侣功能的高分子量复杂结构。然而，随后压力源的去除会诱导该蛋白质结构解离成低分子量蛋白质，并触发分子伴侣到过氧化物酶的功能转换。高分子量 hPrxII 复合物的形成取决于其 N 端过氧化 Cys 残基的过度氧化以及其 C 端结构域，其中包含仅在真核 2-Cys Prxs 中发现的“YF 基序”。 C 末端截短的 hPrxII 以低聚和寡聚蛋白质形式存在，并且不对氧化应激做出反应。此外，hPrxII 的 C 端缺失将其从氧化敏感型过氧化物酶转变为抗超氧化型过氧化物酶。当作为伴侣时，hPrxII 可以保护 HeLa 细胞免遭 H2O2 诱导的细胞死亡，这是通过末端脱氧核苷酸转移酶介导的 dUTP 缺口末端标记测定和荧光激活细胞分选分析来测量的。
Although biochemical properties of 2-Cys peroxire-doxins ( Prxs) have been extensively studied, their real physiological functions in higher eukaryotic cells remain obscure and certainly warrant further study. Here we demonstrated that human ( h) PrxII, a cytosolic isotype of human 2-Cys Prx, has dual functions as a peroxidase and a molecular chaperone, and that these different functions are closely associated with its adoption of distinct protein structures. Upon exposure to oxidative stress, hPrxII assumes a high molecular weight complex structure that has a highly efficient chaperone function. However, the subsequent removal of stressors induces the dissociation of this protein structure into low molecular weight proteins and triggers a chaperone-to-peroxidase functional switch. The formation of a high molecular weight hPrxII complex depends on the hyperoxidation of its N-terminal peroxidatic Cys residue as well as on its C-terminal domain, which contains a "YF motif" that is exclusively found in eukaryotic 2-Cys Prxs. A C-terminally truncated hPrxII exists as low and oligomeric protein species and does not respond to oxidative stress. Moreover, this C-terminal deletion of hPrxII converted it from an oxidation-sensitive to a hyperoxidation-resistant form of peroxidase. When functioning as a chaperone, hPrxII protects HeLa cells from H2O2-induced cell death, as measured by a terminal deoxynucleotidyltransferase-mediated dUTP nick-end labeling assay and fluorescence-activated cell sorting analysis.