Structure of RNA and RNP

x射线晶体学：通过RNA-蛋白复合物的晶体学，分析了它们相互作用的结构细节和RNA在活性中的作用。我们确定了在翻译过程中负责连接相应trna和氨基酸的氨基酰基- trna合成酶的晶体结构。结果表明，trna通过调节蛋白质结构在氨基酰化和校对反应中发挥积极作用。为了分析pre-tRNA成熟的结构基础，我们对负责pre-tRNA加工和修饰的酶进行了结构研究。与ArcTGT络合的tRNA结构表明，修饰是通过包括过渡tRNA结构“λ型”的步骤实现的。我们还测定了参与生殖细胞分化的RNA解旋酶Vasa的晶体结构，并阐明了DEAD-box RNA解旋酶的RNA双链分解的结构基础。核磁共振：(1)测定了人与火焦球菌SRP RNA的螺旋6茎环RNA的溶液结构，并讨论了SRP19识别的差异。(2)测定了嗜热热菌HB8中SmpB的溶液结构，分析了tmRNA与SmpB的相互作用。发现SmpB与tmRNA结合后结构发生改变。(3)确定了从UnaL2 RNA衍生的茎环RNA的溶液结构。五环中的GNRNA基序被发现是LINE逆转录酶识别所必需的，凸起茎的柔韧性被发现对逆转录起始反应很重要。(4)建立了RNA结构分类系统CSNA，并将其应用于核磁共振RNA结构测定。

X-ray crystallography: By crystallography of RNA-protein complexes, structural details of their interactions and roles of RNA in activities were analyzed. We determined crystal structures of aminoacyl-tRNA synthetases, which are responsible for joining corresponding tRNAs and amino acids during translation. It revealed that tRNAs play positive roles in both aminoacylation and proofreading reactions by modulating protein structures. To analyze structural bases of pre-tRNA maturation, structural studies have been done on enzymes responsible for the pre-tRNA processing and modifications. The structure of tRNA complexed with ArcTGT revealed that the modification is achieved via a step including a transitional tRNA structure "λ form". We also determined the crystal structure of Vasa, an RNA helicase involved in the differentiation of germ cells, and elucidated structural basis of the RNA double strand resolution by a DEAD-box RNA helicase.NMR: (1) Solution structures of helix 6 stem-loop RNA of SRP RNA from human and Pyrococcus furiosus were determined and the difference in recognition by SRP19 was discussed. (2) Solution structure of SmpB from Thermus thermophilus HB8 was determined and the interaction between tmRNA and SmpB was analyzed. It was found that the structure of SmpB changed upon binding of tmRNA. (3) Solution structures of stem-loop RNAs derived from UnaL2 RNA were determined. The GNRNA motif in the penta loop was found to be required for the recognition by the LINE reverse transcriptase and the flexibility of the bulged stem was found to be important for the retrotransposition initiation reaction. (4) A classification system for RNA structures, CSNA, was developed and applied for RNA structure determination by NMR.