STRUCTURE OF HELICAL RECA-DNA COMPLEXES - COMPLEXES FORMED IN THE PRESENCE OF ATP-GAMMA-S OR ATP
STRUCTURE OF HELICAL RECA-DNA COMPLEXES - COMPLEXES FORMED IN THE PRESENCE OF ATP-GAMMA-S OR ATP
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DOI：
10.1016/0022-2836(86)90453-5
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发表时间：
1986-10-20
影响因子：
5.6
通讯作者：
STASIAK, A
中科院分区：
文献类型：
--
作者：
EGELMAN, EH;STASIAK, A
RecA-DNA丝，在几种不同的条件下形成的电子显微镜照片，已被分析和三维重建的细丝图像。在ATP和不可水解的ATP类似物ATP-γ-S存在下，RecA蛋白与DNA形成螺距约为95埃的右旋螺旋复合物。在ATP-γ-S存在下，通过分析双链DNA上的RecA细丝获得了细丝的最详细视图。每圈螺旋大约有六个RecA亚基，但这个数量和螺距都是可变的。通过对单纤维和双纤维间相互作用的研究，一幅极其灵活的蛋白质结构的图像出现了。RecA蛋白的亚基被认为是以这样一种方式排列的，即结合的DNA必须部分暴露，并能够与外部DNA分子接触。在ATP-γ-S存在下确定的RecA结构似乎与ATP发生的“突触前”状态相同，其中同源DNA分子之间存在识别和配对。
Electron micrographs of RecA-DNA filaments, formed under several different conditions, have been analyzed and the filament images reconstructed in three dimensions. In the presence of ATP and a non-hydrolyzable ATP analog, ATP-gamma-S, the RecA protein forms with DNA a right-handed helical complex with a pitch of approximately 95 .ANG.. The most detailed view of the filament was obtained from analysis of RecA filaments on double-stranded DNA in the presence of ATP-gamma-S. There are approximately six subunits of RecA per turn of the helix, but both this number and the pitch are variable. From the examination of single filaments and filament-filament interactions, a picture of an extremely flexible protein structure emerges. The subunits of RecA protein are seen to be arranged in such a manner that the bound DNA must be partially exposed and able to come into contact with external DNA molecules. The RecA structure determined in the presence of ATP-gamma-S appears to be the same as the "pre-synaptic" state that occurs with ATP, in which there is recognition and pairing between homologous DNA molecules.