STRUCTURE OF THE ACTIVATED OLIGOMER OF THE ALLOSTERIC ENDONUCLEASE SGRAI

变构核酸内切酶 SGRAI 的活化低聚物的结构

• 批准号: 8362374
• 负责人: Nancy C Horton
• 金额: $ 0.08万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-01 至 2012-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8362374
• 关键词: Bacteriophages; Binding; DNA; DNA Binding; Enzymes; Funding; Genomics; Grant; Head; Invaded; National Center for Research Resources; Principal Investigator; Radiation; Research; Research Infrastructure; Resolution; Resources; Source; Specificity; Structure; United States National Institutes of Health; cost; dimer; endonuclease; structural biology

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. We have discovered that SgrAI, a sequence specific double stranded endonuclease, forms oligomers of the DNA bound form, which activate the enzyme's DNA cleavage activity, and also alter its sequence specificity. The oligomerization may serve to sequester activated enzymes away from the host genomic DNA, and may also serve to rapidly activate the enzyme to protect the host from invading phage. High resolution x-ray crystal structures show the structure of the unoligomerized form (a DNA bound enzyme dimer), and of a potential building block of the oligomer (two DNA bound enzyme dimers associated "head-to-head"). The "head-to-head" associated DNA bound enzyme dimers utilized domain swapping to stabilize, in part, the association, which is quite unusual and unexpected. We hope to characterize, using SAXS, the larger oligomer that is stabilized by binding to DNA that is longer than that used in the crystal structures.

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 我们已经发现，SgrAI，一种序列特异性双链核酸内切酶，形成DNA结合形式的寡聚体，其激活酶的DNA切割活性，并且还改变其序列特异性。寡聚化可用于将活化的酶与宿主基因组DNA隔离，并且还可用于快速活化酶以保护宿主免受噬菌体入侵。 高分辨率X射线晶体结构显示了未寡聚化形式（DNA结合的酶二聚体）和寡聚体的潜在构建单元（两个DNA结合的酶二聚体“头对头”相关）的结构。 “头对头”缔合的DNA结合酶二聚体利用结构域交换来部分稳定缔合，这是非常不寻常和出乎意料的。 我们希望使用SAXS来表征通过与比晶体结构中使用的DNA更长的DNA结合而稳定的较大寡聚体。