STRUCTURE OF THE RECA PROTEIN-ADP COMPLEX
STRUCTURE OF THE RECA PROTEIN-ADP COMPLEX
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DOI：
10.1038/355374a0
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发表时间：
1992-01-23
期刊：
影响因子：
64.8
通讯作者：
STEITZ, TA
中科院分区：
文献类型：
--
作者：
STORY, RM;STEITZ, TA
RecA蛋白催化ATP驱动的DNA分子1-3的同源配对和链交换。它是一种变构酶：ATPase的活性依赖于DNA 4，5，而ATP结合的recA蛋白与DNA具有高亲和力，而ADP结合的形式具有低亲和力6。在没有ATP水解的情况下，recA蛋白仍然可以促进同源配对，显然是通过形成三链中间体1，7-9。ATP水解的确切作用尚不清楚，但它可能会驱动三链中间体向产物1，9，10转化。在这里，我们确定了结合的ADP扩散到recA晶体中的位置。我们发现只有磷酸盐以与其他含有G/AXXXXGKT/S基序的NTPase相同的方式结合。我们认为，recA蛋白可以通过类似于ras癌基因中的p21蛋白的方式在ATP水解时改变其构象。提出了一个模型来解释ATP对DNA结合的变构刺激作用。三磷酸核苷的水解与recA蛋白和p21中另一个配体的结合机制可能是包含这个保守基序的一大类NTPase的典型机制。
THE recA protein catalyses the ATP-driven homologous pairing and strand exchange of DNA molecules 1-3. It is an allosteric enzyme: the ATPase activity is DNA-dependent 4,5, and ATP-bound recA protein has a high affinity for DNA, whereas the ADP-bound form has a low affinity 6. In the absence of ATP hydrolysis, recA protein can still promote homologous pairing, apparently through the formation of a triple-stranded intermediate 1,7-9. The exact role of ATP hydrolysis is not clear, but it presumably drives the triplex intermediate towards products 1,9,10. Here we determine the position of bound ADP diffused into the recA crystal. We show that only the phosphates are bound in the same way as in other NTPases containing the G/AXXXXGKT/S motif. We propose that recA protein may change its conformation upon ATP hydrolysis in a manner analogous to one such protein, the p21 protein from the ras oncogene. A model is presented to account for the allosteric stimulation of DNA binding by ATP. The mechanism by which nucleoside triphosphate hydrolysis is coupled to the binding of another ligand in recA protein and p21 may be typical of the large class of NTPases containing this conserved motif.