Structural Studies of MCM Complex

项目总结：MCM综合体的结构研究 微染色体维持蛋白(MCM)复合体作为解旋酶解开DNA 为DNA复制提供模板，并在调节细胞生长方面发挥关键作用。MCM 解旋酶被认为是细胞DNA复制的许可因素。MCM蛋白质来源 真核生物和古细菌形成六聚体环状复合体，分子量约为0.5-1.0 Mega 多尔顿。尽管进行了广泛的努力，但我们对MCM如何理解仍存在知识差距 解开DNA，MCM在解开过程中如何与DNA相互作用，以及如何利用ATP来驱动 解离所需的MCM的构象变化。MCM在古生菌中保守， 真核生物。真核MCM含有六种形成异六聚体或更高的同系物 订购复合体。然而，一些古菌中的MCM复合体只含有一种MCM蛋白 它们可以组装成同六聚体或十二聚体。因此，古生菌MCM同源低聚物 为理解MCM复合体的结构/功能提供一个更简单的系统。的目标是 这个建议是用古代的MCM复合体作为一个模型系统来理解 MCM复合体的结构/功能，特别强调以下机制 寡聚化、三磷酸腺苷引发的构象变化与DNA结合和重塑 MCM蛋白的功能。结构生物学、生物物理学和功能性的结合 生物化学将被用于这项研究。所得数据将为以下方面提供有价值的信息 了解复制叉处的DNA解卷机制。它还将提供 同源真核MCM复合体的结构/功能研究 与细胞生长调控和癌症生物学的相关性。

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.