Bennett R J, West S C
Imperial Cancer Research Fund, Clare Hall Laboratories South Mimms, Herts, UK.
J Mol Biol. 1995 Sep 15;252(2):213-26. doi: 10.1006/jmbi.1995.0489.
The RuvC protein of Escherichia coli is an endonuclease that specifically recognises and cleaves Holliday junctions during genetic recombination. The structure of the RuvC-Holliday junctions complex has been investigated by DNAse I footprinting and by gel electrophoretic analysis. We find that RuvC binds to the Holliday junction to form a complex that exhibits 2-fold symmetry, and in which the three-dimensional structure of the Holliday junction is altered to an unfolded form. This structure is observed in the absence or presence of divalent metal ions and differs from either the unfolded square or the folded stacked X-structures that have been observed with protein-free Holliday junctions. KMnO4 was used to probe the junction DNA upon binding by RuvC, and indicates that base-pairing at the crossover is disrupted within the RuvC-Holliday junction.
大肠杆菌的RuvC蛋白是一种核酸内切酶，在基因重组过程中能特异性识别并切割霍利迪连接体。已通过DNA酶I足迹法和凝胶电泳分析对RuvC - 霍利迪连接体复合物的结构进行了研究。我们发现，RuvC与霍利迪连接体结合形成一个具有二重对称性的复合物，其中霍利迪连接体的三维结构转变为展开形式。无论有无二价金属离子，均可观察到这种结构，它不同于无蛋白霍利迪连接体所观察到的展开方形或折叠堆叠X形结构。利用高锰酸钾探测RuvC结合后的连接体DNA，结果表明在RuvC - 霍利迪连接体内，交叉处的碱基配对被破坏。
