Target molecule recognition and redox regulation by the chloroplast thioredoxin

A.硫氧还蛋白与其靶蛋白的相互作用我们首次研究了植物胞质硫氧还蛋白（Trx-hl）与胞质苹果酸脱氢酶的相互作用，并成功揭示了该苹果酸脱氢酶是新鉴定的Trx靶蛋白。然后，我们研究了硫氧还蛋白从光合细菌和蓝藻的对应蛋白，揭示了硫氧还蛋白的作用的多样性。此外，还阐明了铁氧还蛋白依赖的硫氧还蛋白还原酶途径和NADPH依赖的硫氧还蛋白还原酶途径在集胞藻6803.B中的作用差异。硫氧还蛋白与靶蛋白相互作用的结构分析硫氧还蛋白为什么能识别分子表面含有氧化还原敏感二硫键的蛋白质作为其靶蛋白，这是一个非常有趣的问题。为了回答这个问题，我们试图用X射线晶体学来解决硫氧还蛋白-靶蛋白复合物的晶体结构。虽然我们试图在各种化学条件下有效地获得复合物，但在研究期间，我们未能建立合适的实验条件以获得复合蛋白质，并且无法解决任何结构，这些结构对于了解可能参与相互作用的氨基酸残基是重要的。

A. Interaction between thioredoxins and their targetsWe first studied the interaction between the plant cytosolic thioredoxin (Trx-hl) and the cytosolic malate dehydrogenase and successfully revealed that this malate dehydrogenase is the newly identified Trx-target protein. We then studied the counterpart proteins of thioredoxins from photosynthetic bacteria and cyanobacteria to reveal the multiplicity of the role of thioredoxins. In addition, we clarified the difference of the roles of two redox-equivalent supply pathways, ferredoxin-dependent thioredoxin reductase pathway and NADPH dependent thioredoxin reductase pathway in the cyanobacteria Synechocystis sp. PCC6803.B. Structural analysis of the protein-protein interaction between thioredoxins and their targets.One of the most interesting questions are why thioredoxins can recognize various proteins, which contains the redox sensitive disulfide bond on the molecular surface, as their target. In order to answer this query, we tried to solve the crystal structures of the thioredoxin-target protein cocomplex using X-ray crystallography. Although we have tried to efficiently obtain the co-complexexes under the various chemical conditions, we failed to set up the suitable experimental conditions to obtain the complex proteins during the research term and could not solve any structures which should be important to know the amino acid residues which may involve into the interaction.