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释放酶，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 具有（SS）DNA，在带有SS-DNA和ADP的三元复合物中 确定为3.0 E和3.2 E的分辨率。 这 二元和三元络合物晶体中的不对称单元 包含两个因重新定位而彼此不同的REP单体 其中一个域，对应于130度的旋转 关于一个铰链区域。 这种大型运动导致关闭 SS-DNA结合涉及裂口。 这样的域运动在 代表二聚体的上下文足够大，可以表明这些 可以通过A耦合到Rep二聚体的易位 亚基的逐步运动。 这些结构代表 与DNA结合的DNA解旋酶的第一视图。