Structural basis of bilateral cleavage in Holliday junction resolution

同源重组是一种自然机制，可以在任何活细胞中发生。使用这种机制，细胞可以将DNA片段，从而将其基因从染色体上的一个位置移动到另一个位置。这是一种机制，允许一个人在混合和匹配基因时，从他/她的母亲那里继承一些性格特征，从他/她的父亲那里继承另一些性格特征。因此，这是一个非常重要的演变过程。当两条染色体(例如，父母各有一条)并排时，每条染色体上的一条DNA链被断裂，然后连接到另一条染色体上断裂的DNA链上。交叉点被称为Holliday连接，能够在两条染色体之间上下滑动，因此最终可以在这两条染色体之间交换少量或大量DNA。我们感兴趣的是，一旦足够的DNA在染色体之间交换，细胞用来‘断开’或‘切断’Holliday连接的机制。细胞通常使用蛋白质来切断Holliday连接，我们之前已经详细研究了其中一种蛋白质(EndoI)的结构。最近，我们制作了一个复杂的模型，展示了EndoI实际上是如何附着在Holliday结上的。对于这项工作，我们想要研究这个综合体的结构。我们特别想：详细研究EndoI/Holliday连接复合体的结构。尝试捕获切割过程中的中间状态，并研究这些中间状态的结构。将这些结构与正在进行的功能研究联系起来，试图重建EndoI用来切断Holliday连接的确切机制。

Homologous recombination is a natural mechanism, which can take place in any living cell. Using this mechanism it is possible for the cell to move segments of DNA, and therefore its genes, from one location on a chromosome to another. This is the mechanism that allows a person to inherit some characterstics from his/her mother, and others from his/her father, as it mixes and matches the genes. It is therefore a very important evolutionary process. When two chromosomes (e.g. one form each parent) are side by side, one strand of DNA on each chromosome is broken and then attached to the broken strand of DNA on the other chromosome. The crossover point, which is called the Holliday junction, is able to slide up and down between the two chromosomes, so that a little or a lot of DNA can ultimately be switched between them. We are interested in the mechanism cell uses to 'break' or 'cut' the Holliday junction once enough DNA has been exchanged between the chromosomes. Cells typically use proteins to cut Holliday junctions and we have previously studied the structure of one of these proteins (EndoI) in fine detail. Very recently, we have been able to make a complex showing how EndoI actually sticks to a Holliday junction. For this work we would like to study the structure of this complex. We would specifically like to: Study the structure of the EndoI / Holliday junction complex in fine detail. Try and trap intermediate states during the cutting process and study the structure of these. Relate these structures to ongoing functional studies to attempt to reconstruct the exact mechanism EndoI uses to cut Holliday junctions.