Departamento de Bioquímica, Biología Celular y Molecular de Plantas, Estación Experimental Zaidin, CSIC 18008 Granada, Spain.
J Plant Physiol. 2010 Apr 15;167(6):423-9. doi: 10.1016/j.jplph.2009.10.017. Epub 2009 Dec 14.
The largest group of plant thioredoxins (TRXs) consists of the so-called h-type; their great number raises questions about their specific or redundant roles in plant cells. Pisum sativum thioredoxin h1 (PsTRXh1) and Pisum sativum thioredoxin h2 (PsTRXh2) are both h-type TRXs from pea (Pisum sativum) previously identified and biochemically characterized. While both are involved in redox regulation and show a high-sequence identity (60%), they display different behavior during in vitro and in vivo assays. In this work, we show that these two proteins display different specificity in the capturing of protein targets in vitro, by the use of a new stringent method. PsTRXh2 interacted with classical antioxidant proteins, whereas PsTRXh1 showed a completely different pattern of targeted proteins, and was able to capture a transcription factor. We also showed that the two proteins display very different thermal and chemical stabilities. We suggest that the differences in thermal and chemical stability point to a distinct and characteristic pattern of protein specificity.
植物硫氧还蛋白（TRXs）中最大的一组是所谓的 h 型；它们的数量众多，这使得人们对它们在植物细胞中的特定或冗余作用产生了疑问。豌豆硫氧还蛋白 h1（PsTRXh1）和豌豆硫氧还蛋白 h2（PsTRXh2）均为豌豆（Pisum sativum）中的 h 型 TRX，之前已被鉴定并进行了生化特性分析。虽然两者都参与了氧化还原调节，并且具有很高的序列同一性（60%），但它们在体外和体内实验中表现出不同的行为。在这项工作中，我们通过使用一种新的严格方法表明，这两种蛋白质在体外对蛋白质靶标的捕获具有不同的特异性。PsTRXh2 与经典的抗氧化蛋白相互作用，而 PsTRXh1 则表现出完全不同的靶蛋白模式，并能够捕获转录因子。我们还表明，这两种蛋白质的热稳定性和化学稳定性差异很大。我们认为，热稳定性和化学稳定性的差异表明了一种独特而有特点的蛋白质特异性模式。
