The in cell structure and function of an intrinsically disordered plant stress protein

由于植物不能移动，它们已经开发出几种机制来在寒冷和干旱等非生物胁迫下生存。随着人为的全球变暖，这些压力可能会变得更加频繁和不可预测。我们的研究计划集中在了解脱水蛋白(脱水蛋白)的结构和功能。基因和蛋白质表达研究表明，脱水蛋白对于植物在这些非生物胁迫下生存是必不可少的。这些蛋白质的功能机制尚未完全阐明。部分问题是，脱水蛋白是高度亲水的蛋白质，这使得它们本质上是无序的。正因为如此，它们不遵循标准的范例，即蛋白质需要有明确的结构并与配体有特定的相互作用才能具有生物功能。我们建议的一个主要部分是使用细胞核磁共振来研究来自葡萄(野生葡萄)的一个最小的(K2脱水蛋白)和一个模型(Ysk2脱水蛋白)的结构和功能。这将需要使用穿透细胞的多肽，以使同位素标记的蛋白质进入葡萄细胞。结果将捕捉到一种天生无序的蛋白质在其自然环境中的结构和行为。我们还将剖析脱水蛋白在DNA结合和保护DNA免受活性氧物种损伤中的作用，活性氧物种是在寒冷和干旱期间形成的。通过确定这些保护蛋白在脱水过程中的作用机制，我们将扩大对脱水蛋白对酶的保护作用的理解。我们还将使用生物信息学的力量来检查脱水蛋白序列的保守性，这是一个不是微不足道的问题，因为由于结构约束的减少，内在无序的蛋白质序列进化的速度要快得多。与此相关，我们还将研究脱水蛋白的进化，并检验我们的假设，即它们是作为有序应激反应蛋白的移码突变而进化的。

Because plants are unable to move, they have developed several mechanisms to survive abiotic stresses such as cold and drought. With anthropogenic global warming these stresses are likely to become more frequent and more unpredictable. Our research proposal centers on understanding the structure and function of dehydrins (dehydration proteins). Genetic and protein expression studies have shown that dehydrins are essential for plants to survive these abiotic stresses. The mechanisms by which these proteins function has not yet been fully elucidated. Part of the issue is that dehydrins are highly hydrophilic proteins, which makes them intrinsically disordered. Because of this, they do not follow the standard paradigm that a protein needs to have a well-defined structure and have specific interactions with a ligand in order to have a biological function. A major part of our proposal is to use in cell NMR to examine the structure and function of a minimal (K2 dehydrin) and model (YSK2 dehydrin) from Vitis riparia (wild grape). This will require the use of cell-penetrating peptides in order to get the isotopically labelled protein inside the grape cell. The results will capture the structure and behaviour of an intrinsically disordered protein in its native environment. We will also dissect dehydrin's role in the binding and protection of DNA from damage caused by reactive oxygen species, which are formed during cold and drought. Our understanding of the protective roles of dehydrins on enzymes will be expanded by determining the mechanism by which these protective proteins function during dehydration. We will also use the power of bioinformatics to examine the conservation of dehydrin sequences, a non-trivial problem given that intrinsically disordered protein sequences evolve at a much faster rate due to reduced structural constrains. Related to this, we will also examine the evolution of dehydrins and test our hypothesis that they evolved as a frameshift mutation of an ordered stress-response protein.**