LEA proteins prevent protein aggregation due to water stress
LEA proteins prevent protein aggregation due to water stress
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DOI：
10.1042/bj20041931
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发表时间：
2005-05-15
影响因子：
4.1
通讯作者：
Tunnacliffe, A
中科院分区：
文献类型：
--
作者：
Goyal, K;Walton, LJ;Tunnacliffe, A
植物和动物中的莱亚（晚期胚胎发生丰富）蛋白与对由干燥和冷激引起的水分胁迫的耐受性相关。然而，尽管已经提出了莱亚蛋白的各种功能，但它们的确切作用还没有被定义。最近的生物信息学研究表明，莱亚蛋白可能具有分子伴侣的功能，本研究旨在验证这一假设。AavLEA1（来自脱水生物线虫燕麦肠线虫的第3组莱亚蛋白）和Em（来自小麦的第I组莱亚蛋白）的重组形式已经进行了功能分析。柠檬酸合酶，这是在高温下容易聚集的热应激实验表明，莱亚蛋白不表现为经典的分子伴侣，但它们确实表现出保护，协同作用的存在下，所谓的化学伴侣，海藻糖。相反，这两个莱亚蛋白可以独立地保护柠檬酸合酶的聚集，由于干燥和冷冻，保持在水胁迫耐受性的作用，获得了类似的结果与乳酸脱氢酶。这是莱亚蛋白由于水分胁迫而具有抗聚集活性的第一个证据。同样，观察到莱亚和海藻糖的协同效应，鉴于已知非还原性二糖在植物和线虫中脱水期间积累，这是显著的。提出了一种模型，据此莱亚蛋白可能作为一种新形式的分子伴侣，或“分子盾”，以帮助防止在水分胁迫期间形成破坏性的蛋白质聚集体。
LEA (late embryogenesis abundant) proteins in both plants and animals are associated with tolerance to water stress resulting from desiccation and cold shock. However, although various functions of LEA proteins have been proposed, their precise role has not been defined. Recent bioinformatics studies suggest that LEA proteins might behave as molecular chaperones, and the current study was undertaken to test this hypothesis. Recombinant forms of AavLEA1, a group 3 LEA protein from the anhydrobiotic nematode Aphelenchus avenae, and Em, a group I LEA protein from wheat, have been subjected to functional analysis. Heat-stress experiments with citrate synthase, which is susceptible to aggregation at high temperatures, suggest that LEA proteins do not behave as classical molecular chaperones, but they do exhibit a protective, synergistic effect in the presence of the so-called chemical chaperone, trehalose. In contrast, both LEA proteins can independently protect citrate synthase from aggregation due to desiccation and freezing, in keeping with a role in water-stress tolerance; similar results were obtained with lactate dehydrogenase. This is the first evidence of anti-aggregation activity of LEA proteins due to water stress. Again, a synergistic effect of LEA and trehalose was observed, which is significant given that non-reducing disaccharides are known to accumulate during dehydration in plants and nematodes. A model is proposed whereby LEA proteins might act as a novel form of molecular chaperone, or,molecular shield', to help prevent the formation of damaging protein aggregates during water stress.