Lab Ecophysiol Molecul Plantes, Saint-Paul-lez-Durance, France.
Antioxid Redox Signal. 2012 Jan 1;16(1):79-84. doi: 10.1089/ars.2011.4153. Epub 2011 Sep 1.
Reactive oxygen species fulfill key roles in development and signaling, but lead at high concentration to damage in macromolecules. In proteins, methionine (Met) is particularly prone to oxidative modification and can be oxidized into Met sulfoxide (MetO). MetO reduction is catalyzed by specialized enzymes, termed methionine sulfoxide reductases (MSRs), involved in senescence and protection against diseases and environmental constraints. The precise physiological functions of MSRs remain often elusive because of very poor knowledge of their substrates. In this study, affinity chromatography was used to isolate partners of Arabidopsis thaliana plastidial methionine sulfoxide reductase B1 (MSRB1). Twenty-four proteins involved in photosynthesis, translation, and protection against oxidative stress, as well as in metabolism of sugars and amino acids, were identified. Statistical analysis shows that the abundance of MSRB1 partners in chromatography affinity samples is proportional to Met content. All proteins, for which structural modeling was feasible, display surface-exposed Met and are thus potentially susceptible to oxidation. Biochemical analyses demonstrated that H(2)O(2) treatment actually converts several MSRB1-interacting proteins into MSRB substrates. In consequence, we propose that affinity chromatography constitutes an efficient tool to isolate physiological targets of MSRs.
活性氧在发育和信号转导中发挥关键作用，但在高浓度下会导致大分子物质的损伤。在蛋白质中，蛋氨酸（Met）特别容易发生氧化修饰，可以被氧化成 Met 亚砜（MetO）。MetO 的还原由专门的酶（称为蛋氨酸亚砜还原酶（MSRs））催化，这些酶参与衰老以及对疾病和环境限制的保护。由于对其底物的了解非常有限，因此 MSRs 的精确生理功能仍然难以捉摸。在这项研究中，亲和层析被用于分离拟南芥质体蛋氨酸亚砜还原酶 B1（MSRB1）的伴侣。鉴定出了 24 种参与光合作用、翻译以及对氧化应激和糖及氨基酸代谢保护的蛋白质。统计分析表明，色谱亲和样品中 MSRB1 伴侣的丰度与 Met 含量成正比。对于所有可进行结构建模的蛋白质，都显示出表面暴露的 Met，因此容易受到氧化。生化分析表明，H2O2 处理实际上会将几种与 MSRB1 相互作用的蛋白质转化为 MSRB 的底物。因此，我们提出亲和层析是分离 MSRs 生理靶标的有效工具。
