Molecular mechanisms of branch migration and resolution of Holliday junctions

我们研究了RuvA和RuvB蛋白复合物、驱动Holliday连接分支迁移的RecG蛋白和核酸内切分解Holliday连接的RuvC蛋白的反应机制和功能。在复制起点形成环状结构，负调控复制的起始。2.我们研究了RuvC解离酶的底物特异性，3.克隆并分析了铜绿假单胞菌的ruvA、ruvB和ruvC基因，发现它们的基因排列与大肠杆菌的基因排列不同，但具有相似的功能。表达了嗜热栖热菌ruvB基因，并对RuvB蛋白进行了鉴定。5.对ruv突变体和recG突变体进行了形态学研究，发现这些突变体中的失败重组抑制了染色体不分离。

We studied reaction mechanisms and functions of RuvA and RuvB protein complex and RecG protein which drives branch migration of Holliday junctions and RuvC protein which endonucleolytically resolves Holliday junctions.1.We discovered that RecG protein has a unique function to resolve the R-loops formed at the replication origin and negatively regulate the initiation of replication.2.We studied the substrate specificity of RuvC resolvase with various synthetic Holliday junctions and found that the existence of thymine residue at or near crossover point is important but the sequence homology at the junction is not important for the cleavage.3.We cloned and analyzed the ruvA,ruvB and ruvC genes of Pseudomonas aeruginosa and found that although the arrangement of the genes are different from that of the Escherichia coli genes, they possess the similar functions.4.We cloned, expressed the Thermus thermophilus ruvB gene and characterized the RuvB protein.5.We studied the morphology of ruv mutants and recG mutants and found that the abortive recombination in these mutants inhibit the chromosome nondisjunction.