Baliga R, Singleton J W, Dervan P B
Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena 91125, USA.
Proc Natl Acad Sci U S A. 1995 Oct 24;92(22):10393-7. doi: 10.1073/pnas.92.22.10393.
Escherichia coli RecA protein, in the presence of ATP or its analog adenosine 5'-[gamma-thio]triphosphate, polymerizes on single-stranded DNA to form nucleoprotein filaments that can then bind to homologous sequences on duplex DNA. The three-stranded joint molecule formed as a result of this binding event is a key intermediate in general recombination. We have used affinity cleavage to examine this three-stranded joint by incorporating a single thymidine-EDTA.Fe (T*) into the oligonucleotide part of the filament. Our analysis of the cleavage patterns from the joint molecule reveals that the nucleoprotein filament binds in the minor groove of an extended Watson-Crick duplex.
在ATP或其类似物腺苷5'-[γ-硫代]三磷酸存在的情况下，大肠杆菌RecA蛋白会在单链DNA上聚合形成核蛋白细丝，该细丝随后可与双链DNA上的同源序列结合。这种结合事件形成的三链连接分子是一般重组中的关键中间体。我们通过将单个胸腺嘧啶-乙二胺四乙酸铁（T*）掺入细丝的寡核苷酸部分，利用亲和切割来检测这种三链连接。我们对连接分子切割模式的分析表明，核蛋白细丝结合在延伸的沃森-克里克双链体的小沟中。
