Structural Plasticity of Intrinsically Disordered LEA Proteins from Xerophyta schlechteri Provides Protection In Vitro and In Vivo
Structural Plasticity of Intrinsically Disordered LEA Proteins from Xerophyta schlechteri Provides Protection In Vitro and In Vivo
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DOI：
10.3389/fpls.2019.01272
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发表时间：
2019-10-10
影响因子：
5.6
通讯作者：
Hilhorst, Henk
中科院分区：
文献类型：
--
作者：
Artur, Mariana A. Silva;Rienstra, Juriaan;Hilhorst, Henk
胚胎发生后期丰富的LEA蛋白对复活植物和正统种子保护亚细胞环境免受与干燥相关的不可逆损伤的能力至关重要。在本研究中，我们研究了单子叶复活植物旱生植物（XsLEAs）在干燥过程中表达的6种LEA蛋白的结构和功能。计算机分析表明XsLEAs是具有可变内在无序蛋白（IDP）特性的亲水性蛋白。圆二色性（CD）分析表明，这些蛋白在水中大多是非结构化的，但在疏水溶液中获得二级结构，表明结构动力学可能在其亚细胞环境中的功能中起作用。XsLEAs具有保护乳酸脱氢酶（LDH）抵抗干燥、高温和氧化胁迫的能力，并能在渗透和盐胁迫下抑制大肠杆菌的生长。亚细胞定位分析表明，XsLEA重组蛋白在烟叶细胞质、膜和细胞核中存在差异分布。有趣的是，一个LEA_1家族蛋白（XsLEA1-8）在体外和体内表现出最高的无序倾向和保护能力，也能增强拟南芥的耐盐和干旱胁迫能力。总之，我们的研究结果表明，XsLEAs的结构可塑性对其保护活性至关重要，以避免水分亏缺胁迫引起的各种亚细胞成分的损伤。XsLEA1-8是植物体外工程结构稳定性和提高水分亏缺胁迫耐受性的潜在模式蛋白。
Late embryogenesis abundant (LEA) proteins are essential to the ability of resurrection plants and orthodox seeds to protect the subcellular milieu against irreversible damage associated with desiccation. In this work, we investigated the structure and function of six LEA proteins expressed during desiccation in the monocot resurrection species Xerophyta schlechteri (XsLEAs). In silico analyses suggested that XsLEAs are hydrophilic proteins with variable intrinsically disordered protein (IDP) properties. Circular dichroism (CD) analysis indicated that these proteins are mostly unstructured in water but acquire secondary structure in hydrophobic solution, suggesting that structural dynamics may play a role in their function in the subcellular environment. The protective property of XsLEAs was demonstrated by their ability to preserve the activity of the enzyme lactate dehydrogenase (LDH) against desiccation, heat and oxidative stress, as well as growth of Escherichia coli upon exposure to osmotic and salt stress. Subcellular localization analysis indicated that XsLEA recombinant proteins are differentially distributed in the cytoplasm, membranes and nucleus of Nicotiana benthamiana leaves. Interestingly, a LEA_1 family protein (XsLEA1-8), showing the highest disorder-to-order propensity and protective ability in vitro and in vivo, was also able to enhance salt and drought stress tolerance in Arabidopsis thaliana. Together, our results suggest that the structural plasticity of XsLEAs is essential for their protective activity to avoid damage of various subcellular components caused by water deficit stress. XsLEA1-8 constitutes a potential model protein for engineering structural stability in vitro and improvement of water-deficit stress tolerance in plants.