Structural Studies of MCM Complex

项目概要：MCM配合物的结构研究 微小染色体维持蛋白（MCM）复合物作为解旋酶发挥作用，解旋DNA 为DNA复制提供模板，并在调节细胞生长中起关键作用。MCM 解旋酶被认为是细胞DNA复制的许可因素。MCM蛋白， 真核生物和古细菌形成六聚体环复合体，MWt约为0.5-1.0 Mega 多尔顿尽管我们做了大量的努力，但在了解MCM如何 解旋DNA，MCM在解旋过程中如何与DNA相互作用，以及如何利用ATP来驱动DNA解旋。 解旋所需的MCM的构象变化。MCM在古细菌中是保守的， 真核生物真核MCM含有六种形成异源六聚体的同源物， 秩序情结然而，某些古细菌中的MCM复合物仅含有一种MCM蛋白 可以组装成同源六聚体或十二聚体。因此，古细菌MCM同源寡聚物 为了解MCM复合物的结构/功能提供了一个更简单的系统。的目标 这个建议是使用古菌MCM复合体作为模型系统来理解 结构/功能的MCM复杂，特别强调的机制， 寡聚化、ATP引发的构象变化以及DNA结合和重塑 MCM蛋白的功能。结构生物学、生物物理学和功能生物学的结合 生物化学将用于该研究。由此产生的数据将提供有价值的信息， 了解复制叉处的DNA解旋机制。它还将提供 同源真核MCM复合物的结构/功能见解，其具有高 与细胞生长调节和癌症生物学相关。

Project Summary: Structural studies of MCM complex Minichromosome maintenance protein (MCM) complex functions as a helicase that unwinds DNA to provide template for DNA replication and plays a critical role in regulating cell growth. MCM helicases are considered to be a licensing factor for cellular DNA replication. MCM proteins from eukaryotes and archaea form hexamers ring complex, with MWt approximating 0.5-1.0 Mega Dolton. Despite extensive efforts, gap of knowledge exists in our understanding of how MCM unwinds DNA, how MCM interacts with DNA during unwinding, and how ATP is utilized to drive the conformational changes of MCM needed for unwinding. MCM are conserved in archaea and eukaryotes. Eukaryotic MCM contains six homologs that form hetero-hexamer and possibly higher order complexes. However, the MCM complex in some archaea contains only one MCM protein that can assemble into homo-hexamers or dodecamers. Thus, archaeal MCM homo-oligomers provide a simpler system for understanding the structure/function of MCM complex. The goal of this proposal is to use archaeal MCM complexes as a model system to understand the structure/functions of MCM complex, with particular emphasis on the mechanisms regarding oligomerization, ATP-triggered conformational changes, and DNA binding and remodeling functions of MCM proteins. A combination of structural biology, biophysics, and functional biochemistry will be employed for the study. The resulting data will provide valuable information for understanding the DNA unwinding mechanism at the replication fork. It will also provide structural/functional insights for the homologous eukaryotic MCM complex, which bears high relevance to cell growth regulation and cancer biology.