STRUCTURAL STUDIES OF NUCLEIC ACID MOTORS

我们正在使用X射线结晶学方法研究解旋酶的机制和组装，以深入了解DNA复制和核输出，这是缺陷导致癌症的两条途径。特别是，通过对噬菌体T7的解旋酶/启动酶的结构研究，我将阐述DNA解离的机制，以确定六聚体T7解旋酶/启动酶是采用类似F1-ATPase的结合变化机制，还是采用类似二聚体螺旋酶的机制。我还希望通过确定T7解旋酶/启动酶和单链DNA结合蛋白之间的复合体的晶体结构来深入了解复制叉处的组装。我对mRNA输出因子RAT8/Dbp5的结构研究主要集中在伴随着RAT8/Dbp5从细胞核到核孔再到细胞质的蛋白质-蛋白质相互作用。这将通过测定RAT8/Dbp5单独的晶体结构以及与其在核孔上的相互作用伙伴RAT7/Nup159的络合物来实现。

We are studying the mechanism and assembly of helicases using x-ray crystallographic methods in order to gain insight into DNA replication and nuclear export, two pathways in which defects can cause cancer. In particular, through structural investigations of the helicase/primase from bacteriophage T7, I will address the mechanism of DNA unwinding to determine whether the hexameric T7 helicase/primase adopts a mechanism similar to the binding-change mechanism of F1-ATPase or a mechanism similar to dimeric helicases. I also expect to gain insight into assembly at the replication fork through the crystal structure determination of a complex between the T7 helicase/primase and single- stranded DNA binding protein. My structural studies on the mRNA export factor RAT8/Dbp5 focus on the protein-protein interactions that accompany the shuttling of RAT8/Dbp5 from the nucleus to the nuclear pore and finally to the cytoplasm. This will be accomplished through crystal structure determination of RAT8/Dbp5 alone and in complex with RAT7/Nup159, its interaction partner at the nuclear pore.