DESIGNED DNA CRYSTALS

设计的 DNA 晶体

基本信息

批准号：
8363350
负责人：
JENS J BIRKTOFT
金额：
$ 0.71万
依托单位：
BROOKHAVEN SCIENCE ASSOC-BROOKHAVEN LAB
依托单位国家：
美国
项目类别：
财政年份：
2011
资助国家：
美国
起止时间：
2011-07-01 至 2012-06-30
项目状态：
已结题

项目摘要

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Our research program is designed to utilize new types of macromolecular building blocks based on branched DNA, as the basis of specifically designed crystalline arrangements 3D structural motifs. The ultimate goals are to provide macromolecular scaffoldings, capable of binding, orienting and juxtaposing a variety of molecules, from biological macromolecules to organic conductors and optical memory components. We proposed and succeeded in determining structures of such a designed 3D system, the tensegrity triangle. This structure is a robust motif with three-fold rotational backbone symmetry, consisting of three helices that are directed in linearly independent directions, i.e., their helix axes do not all share the same plane. The helices are connected pair-wise by three Holliday-like crossover points, so as to produce an alternating over-and-under motif. Recently, we reported [Zheng et al. Nature 461, 74-77 (2009)] the X-ray crystal structure to 4 ¿ of a tensegrity triangle containing a single molecular species, comprised of three helical domains, each containing two double helical turns. Each triangle is centered on a vertex of a rhombohedron, creating a large cavity. Our more recent efforts have been directed in several different directions, all based on the structure of the published two-turn triangle. (A) We have been successful in increasing the numbers of helical turns in the triangle from 2 to 3 and 4 and in determining their crystal structures. While the refined structures all have the structural parameters predicted from their designs, the resolutions of the crystals obtained decrease with the increase in the number of helical turns. We are exploring the effect of changing the length of sticky ends that link the triangles, and also the impact of using natural DNA, rather than synthetic DNA, on the resolution of the crystals. (B) We are attempting to incorporate guest molecules into the internal cavities of the crystal structures; the cavities of the three structures with different length edges (2, 3 and 4 turns) are ~100 nm3, ~375 nm3 and ~1000 nm3. The guest species range from proteins, peptides, and peptidomimetics to dyes, metallic nanoparticles and segments of DNA. Isomorphous crystals have been obtained of such complexes both by co-crystallization and soaking. A report describing the crystal structure of a DNA crystal containing two distinct triangles programmed to crystallize according to the design is ready for submission. In addition, we have also demonstrated that the colors of the crystals can be controlled by the covalent attachment of dye molecules to the different molecules. As a rule our crystals are weakly diffracting, display a high degree of mosaicity and frequently appear in space group P1. Consequently the crystals require long exposure times, small oscillation angles and optimally data collection over 360 degrees.

该副本是利用资源的众多研究子项目之一由NIH/NCR资助的中心赠款。而且，副投影的主要研究员可能是其他来源提供的包括其他NIH来源。代表subproject使用的中心基础架构的估计量， NCRR赠款向子弹或副个人投资人员提供了直接资金。我们的研究计划是针对分支DNA D晶体排列的大分子构建块3D结构图案。 SUK GNED 3D系统的结构，紧张的三角形是一个稳健的基序，带有三倍旋转的骨干对称性t，以线性独立的方向（即HELICE共享）。我们最近报告了主题。一个由三个螺旋结构域组成的张力三角形的三角形，每个分子都围绕着两个双螺旋旋转。我们最近的指示是不同的指示，所有这些都基于公开的三角三角形。从其设计中预测的结构参数随着螺旋旋转数量的增加而降低。 DNA，晶体分子。 DNA的纳米颗粒和纳米晶体是通过共结晶和浸泡来获得的还证明了晶体的颜色可以通过染料分子的染料分子共价。