CRYSTALLOGRAPHIC STUDIES OF DNA HELICASES

DNA 解旋酶的晶体学研究

• 批准号: 6119395
• 负责人: GABRIEL WAKSMAN
• 金额: --
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-03-01 至 2000-04-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6119395
• 关键词: biomaterials; proteins

Rep DNA helicase is a DNA unwinding enzyme which together with helicase II is essential for DNA replication and repair in E. coli. Crystal structures of the E. coli Rep helicase in a binary complex with (ss) DNA and in a ternary complex with ss-DNA and ADP were determined to a resolution of 3.0 E and 3.2 E, respectively. The asymmetric unit in the crystals of the binary and ternary complexes contains two Rep monomers differing from each other by a reorientation of one of the domains, corresponding to a swiveling of 130 degree about a hinge region. This large motion results in the closing of a cleft involved in ss-DNA binding. Such domain movements, within the context of the Rep dimer, are sufficiently large to suggest that these may be coupled to translocation of the Rep dimer along DNA by a step-wise movement of the subunits. These structures represent the first view of a DNA helicase bound to DNA.

Rep DNA 解旋酶是一种 DNA 解旋酶，它与 解旋酶 II 对于大肠杆菌中的 DNA 复制和修复至关重要。 二元复合物中大肠杆菌 Rep 解旋酶的晶体结构 与 (ss) DNA 以及与 ss-DNA 和 ADP 的三元复合物 分辨率分别为 3.0 E 和 3.2 E。 这 二元和三元配合物晶体中的不对称单元 包含两个通过重新取向而彼此不同的 Rep 单体 其中一个域的，对应于 130 度的旋转 关于铰链区域。 这个大的运动导致关闭 参与 ss-DNA 结合的裂缝。 这种域运动，在 Rep二聚体的背景足够大，表明这些 可以通过以下方式与 Rep 二聚体沿着 DNA 的易位偶联： 子单元的逐步运动。 这些结构代表 DNA 解旋酶与 DNA 结合的第一视角。