Protein stability in Artemia embryos during prolonged anoxia
Protein stability in Artemia embryos during prolonged anoxia
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DOI：
10.2307/25066582
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发表时间：
2007-02-01
影响因子：
1.6
通讯作者：
Clegg, James S.
中科院分区：
文献类型：
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作者：
Clegg, James S.
卤虫（Artemia franciscana）的包囊胚胎（包囊）可以说是所有动物生命史阶段中最具抗应激性的。它们的许多适应性之一是能够忍受缺氧多年，同时完全水合和生理温度。以前的工作表明，缺氧胚胎的整体代谢被带到一个可逆的停顿，包括自由能的转导和大分子的周转。但蛋白质在三级和四级结构水平上的稳定性问题没有得到研究。在这里，我提供的证据表明，绝大多数蛋白质不可逆地失去其天然构象在多年的缺氧，尽管没有可检测的蛋白质周转。虽然发生适度的蛋白质变性和聚集，但通过短暂的缺氧后需氧孵育可迅速逆转。我认为如何实现这种非凡的稳定性，并建议至少部分的答案涉及大量的小热休克蛋白（p26），作为分子伴侣，其功能似乎并不需要核糖核苷二或三磷酸。
Encysted embryos (cysts) of the brine shrimp, Artemia franciscana, are arguably the most stress-resistant of all animal life-history stages. One of their many adaptations is the ability to tolerate anoxia for periods of years, while fully hydrated and at physiological temperatures. Previous work indicated that the overall metabolism of anoxic embryos is brought to a reversible standstill, including the transduction of free energy and the turnover of macromolecules. But the issue of protein stability at the level of tertiary and quaternary structure was not examined. Here I provide evidence that the great majority of proteins do not irreversibly lose their native conformation during years of anoxia, despite the absence of detectable protein turnover. Although a modest degree of protein denaturation and aggregation occurs, that is quickly reversed by a brief postanoxic aerobic incubation. I consider how such extraordinary stability is achieved and suggest that at least part of the answer involves massive amounts of a small heat shock protein (p26) that acts as a molecular chaperone, the function of which does not appear to require ribonucleoside di- or tri-phosphates.