RESTRICTION ENDONUCLASE SFII

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。 SfiI是一种四聚体核酸内切酶，需要结合两个DNA双链体才能成功激活和协调切割所有四条链。我们已经解决了与DNA复合的酶的天然形式的结构，并且结构表明单体之间存在串扰，这是SfiI的变构激活的原因。我们现在有一个突变体（Y 68 F），它仍然是四聚体，但优先结合和切割一个ds DNA。我们有这种突变体的晶体，它在母源处衍射到4-4.5 A。我们希望收集高分辨率数据，以揭示Y 68在SfiI变构激活中的作用。

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. SfiI is a teterameric endonuclease that requires the binding of two DNA duplexes for successful activation and concerted cleavage of all four strands. We have solved the structure of the native form of the enzyme in complex with DNA and the structure indicates that there is a cross-talk between monomers that is responsible for allosteric activation of SfiI. We now have a mutant (Y68F)that is still tetrameric but preferentially binds and cleaves one ds DNA. We have crystals of this mutant that diffracts to 4-4.5 A at the home source. We are looking to collect high resolution data to uncover the role of Y68 in the allosteric activation of SfiI.