固有无序蛋白--大豆LEA蛋白（GmPM1）提高植物耐盐性的分子基础

LEA蛋白是调控植物抗逆性的重要功能蛋白，其功能发挥依赖于LEA蛋白的抗逆保护作用。LEA蛋白属固有无序蛋白，在天然状态下其结构灵活易变。在高盐胁迫下，高柔性结构的LEA蛋白如何识别不同的配体、如何行使多重保护作用的机理还不清楚。利用烟草悬浮细胞及酵母缺失突变体，我们的前期研究已经确认了大豆LEA蛋白-GmPM1的耐盐保护作用；也证明了全长的PM1蛋白可与多种配体结合。本项目拟在以上研究的基础上，进一步根据PM1蛋白序列可能的螺旋结构及碱性氨基酸分布特点，构建不同的缺失克隆；并利用示差扫描量热法、等温滴定量热法、CD光谱和核磁共振技术，研究PM1蛋白（及缺失短肽）与不同配体（如脂质体、多种金属离子和DNA）的相互作用，剖析PM1蛋白与不同配体结合后的二级结构、三维结构（构象）的变化及其与不同保护功能的关系，以期阐明LEA蛋白"序列-结构-抗逆保护功能"的分子基础，为抗逆分子育种提供理论依据

LEA proteins play significant roles in improving plant stress tolerance. They belong to the family of intrinsically disordered proteins （IDPs）. It is still unclear about these flexible LEA proteins how to recognize different ligands and exercise multiple protection under salt stress in plant. Our previous study has confirmed that ectopic expression of the soybean LEA protein GmPM1 who can bind various ligands confers salt-tolerance to tobacco suspension cells and yeast deletion mutants. Here, different truncated polypeptides of PM1 protein will be constructed according to the characteristics of helix structure and the distribution of alkaline amino acids. In vitro, some biophysical and biotechnological methods (differential scanning calorimetry, isothermal titration calorimetry, CD spectrum and NMR resonance technique) will be used to analyze the interaction of PM1 protein (truncated peptides) with different ligands (such as liposome, metal ions and DNA). The convertion in secondary structure and three-dimensional structure of PM1 protein after binding defferent ligands will also be studied in vitro. In conclusion, this study plans to display the relevance among LEA protein peptide sequence, structure and function in protecting plant from stress damage and provide significant basis for plant molecular-breeding engineering in stress tolerance.