Program in Macromolecular Structure, Motion, Control

生物化学、分子遗传学和高分辨率X射线晶体学实验将用于 建立与DNA相互作用的蛋白质（和酶）的功能机制的结构基础， RNA，主要侧重于大分子组装。特别感兴趣的是蛋白质和 参与促进复制，基因表达和重组过程的核酸-中央 分子生物学的教条。为了进一步阐明蛋白质合成过程中各个步骤的作用机制， 合成，我们希望获得在蛋白质合成周期中尽可能多的步骤中捕获的核糖体晶体 并以尽可能高的分辨率建立其结构。其结构将 1）70S核糖体与结合的m-RNA、tRNA和延伸因子Tu， 氨酰-tRNA或延伸因子G的复合物; marismortui SOS亚基与 信号识别颗粒，和3）70S核糖体或其SOS亚基与 蛋白质分泌和膜蛋白插入通道，转位子。为了探究 细菌核糖体及其来自真核生物的大得多的对应物，40S亚基，60S亚基， 亚基和/或80S核糖体，包括与IRIS RNA形成的起始复合物，并使用核糖体 从酵母或兔网织红细胞中分离。探讨抗生素的结构基础 特异性，RNA形成H的肽基转移酶中心。marismortui 50 S亚基将被替换为 对应于真细菌或真核生物大亚基rRNA的RNA序列及其与以下的复合物的RNA序列， 抗生素研究为了进一步了解位点特异性重组酶，γ-δ解离酶， 与两个115个碱基对的DNA形成突触复合物并实现重组，整个12个碱基对的结构 将使用突变的γ-δ解离酶测定与DNA的亚基复合物。为了深入了解mRNA剪接 将研究II组内含子自剪接RNA的结构。为了探索 产生一些古细菌使用的cys-tRNACys，Phe-tRNA合成酶的古细菌直系同源物的结构， 具有磷酸丝氨酸的氨基酰化tRNACys将与结合的适当底物建立。

Biochemical, molecular genetic and high resolution X-ray crystallographic experiments will be used to establish the structural bases for the functional mechanisms of proteins (and enzymes) that interact with DNA or RNA, with a major emphasis on large macromolecular assemblies. Of particular interest are the proteins and nucleic acids involved in facilitating the processes of replication, gene'expression and recombination - the Central Dogma of Molecular Biology. To further illuminate the mechanisms of each step in the process of protein synthesis, we wish to obtain crystals of the ribosome trapped in as many of the steps in the protein synthesis cycle as possible and to establish their structures at the highest resolution possible. The complexes whose structures will be pursued include those of the 1) 70S ribosome with bound m-RNA, tRNA and either elongation factor Tu with aminoacyl-tRNA or elongation factor G, 2) the complex of the H. marismortui SOS subunit with fragments of the signal recognition particle, and 3) complexes between either the 70S ribosome or its SOS subunit complexed with the protein secretion and membrane protein insertion channel, the translocon. To explore the differences between the bacterial ribosome and its much large counterpart from eukaryotes, the structures of the 40S subunit, the 60S subunit and/or the 80S ribosome, including an initiation complex formed with IRIS RNA, and using ribosomes isolated from either yeast or rabbit reticulocyte will be pursued. To explore the structural basis of antibiotic specificity, the RNA forming the peptidyl transferase center of H. marismortui 50 S subunit will be replaced by RNA sequences corresponding to those of eubacterial or eukaryotic large subunit rRNA and their complexes with, antibiotics studied. To further understand the mechanism by which the site specific recombinase, gamma-delta resolvase, forms a synaptic complex with two 115 base-pair DNAs and achieves recombination, the structure of the entire 12 subunit complex with DNA will be determined using mutant gamma-delta resolvase. To gain insights into m-RNA splicing the structure of group II intron self-splicing RNA will be pursued. In order to explore the alternate pathway of producing cys-tRNACys used by some archaea, the structure of the archaeal ortholog of Phe-tRNA synthetase that amino acylates tRNACys with phosphoserine will be established with the appropriate substrates bound.