DNA ENZYME DATA COLLECTION

同步辐射是从弱辐射中收集数据的关键 大分子核酸的衍射晶。结构性 这个项目的研究重点是一种DNA酶，它可以用来裂解RNA 高特异性。结合的DNA：RNA复合体已经结晶 在六方空间群P6(1)22中，结构已经 使用5个重原子导数测定，并在3.0℃精炼 E解决方案。82个核苷酸的DNA：RNA复合体的结构 显示六方晶体中的DNA酶已重新排列 形成一个由保守序列中的复古序列介导的二聚体 酶的核心。然而，该结构提供了一个原子 四链结构Holliday结的分辨模型 是基因重组所必需的。为了捕获一名活跃的 DNA酶的构象--组合结晶筛选 已经使用3880个个体对81个序列变体进行了研究 条件。这块屏幕已经产生了40种新的晶体形态。这些 需要评估晶体形态的衍射特性和 结构需要采用最好的晶体形式 决定。这些研究将为我们提供对 DNA酶的作用机制。这一机制与酶有关。 功能，并与该功能相关的基本利益 核酶和蛋白质酶。DNA酶目前正在被 在临床试验中使用，因此结果也与 治疗应用。

Synchrotron radiation is essential for data collection from weakly diffracting crystals of macromolecular nucleic acids. Structural studies in this project focus on a DNA enzyme that cleaves RNA with high specificity. The combined DNA:RNA complex has been crystallized in the hexagonal space group P6(1)22, and the structure has been determined with the use of 5 heavy atom derivatives and refined at 3.0 E resolution. The structure of the 82-nucleotide DNA:RNA complex reveals that the DNA enzyme in the hexagonal crystals has rearragned to form a dimer mediated by a palidromic sequence in the conserved core of the enzyme. However, the structure provides an atomic resolution model for Holliday junctions, a 4-stranded structure required for genetic recombination. In order to capture an active conformation of the DNA enzyme a combinatorial crystallization screen has been carried out on 81 sequence variants using 3880 individual conditions. The screen has resulted in 40 new crystal forms. These crystal forms need to be evaluated for diffraction characteristics and the best crystal forms need to be employed for structure determinations. These studies will provide critical insight into the mechanism of the DNA enzyme. This mechanism is relevant to the enzyme function and is of fundamental interest with respect to the function of ribozymes and protein enzymes. The DNA enzyme is currently being used in clinical trials and so the results are also relevant to therapeutic applications.