FOLDING OF AN IMMOBILE DNA BRANCHED JUNCTION

固定 DNA 分支连接的折叠

• 批准号: 6205712
• 负责人: NADRIAN C. SEEMAN
• 金额: --
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-09-01 至 2000-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6205712
• 关键词: biological products; biomedical resource; biotechnology; enzymes; growth /development; nucleic acids; proteins; radiology; spectrometry; technology /technique

Many macromolecular folding reactions, such as the Mg2+-dependent folding of the Tetrahymena thermophila group I intron, occur on timescales ranging from milliseconds to minutes. Kinetic progress curves describing the millisecond folding of P4-P6 and other domains within the L-21 ribozyme have been obtained using a new OH footprinting technique, stopped-flow synchrotron x-ray footprinting. The folding of P4-P6 is a highly concerted reaction; the regions of OH protection within the interior of the folded domain appear at rates of ? 1.0 sec-1. OH protections within the P5c sub-domain appear at rates of ~ 2.0 sec-1, suggesting that folding of this subdomain is the initial step in the folding pathway. The rates of OH protection of the triple helix junction between P4-P6 and the P3-P7 domain and those protections in P4-P6 ascribed to interaction with the P9 domain at rates of ~ 0.3 sec-1. These results suggest that these tertiary interactions guide the folding of the catalytic core against an extensively folded P4-P6 domain. To further dissect the folding mechanism of the Tetrahymena ribozyme, which we have solved in detail for a single set of conditions, the magnesium and temperature dependence of the folding mechanism will be explored in order to correlate the changes in energetics and structure that occur along the folding pathway.

许多大分子折叠反应，例如Mg 2+依赖性 嗜热四膜虫I组内含子的折叠，发生在 从毫秒到分钟的时间尺度。 动力学进展 描述P4-P6和其他区域毫秒折叠的曲线 在L-21核酶已获得使用一种新的 哦 足迹 停流同步加速器X射线技术 足迹. P4-P6的折叠是高度协同的反应; 折叠结构域内部的OH保护出现在 率？1.0秒-1。 P5 c子域内的OH保护 出现的速度约为2.0秒-1，这表明这种折叠 亚结构域是折叠途径的起始步骤。 率 OH保护 三螺旋 P4-P6和 P3-P7结构域和P4-P6中的相互作用保护 与P9结构域以约0.3秒-1的速率。 这些结果表明 这些三级相互作用引导催化剂的折叠， 针对广泛折叠的P4-P6结构域的核心。 为了进一步剖析 四膜虫核酶的折叠机制， 详细解决了一组条件，镁和 折叠机制的温度依赖性将在 为了将能量和结构的变化联系起来， 沿着折叠路径。