Darst R P, Wang D, Auble D T
Department of Biochemistry and Molecular Genetics, University of Virginia Health Science Center, Charlottesville, VA 22908-0733, USA.
EMBO J. 2001 Apr 17;20(8):2028-40. doi: 10.1093/emboj/20.8.2028.
SNF2/SWI2-related ATPases employ ATP hydrolysis to disrupt protein-DNA interactions, but how ATP hydrolysis is coupled to disruption is not understood. Here we examine the mechanism of action of MOT1, a yeast SNF2/SWI2-related ATPase that uses ATP hydrolysis to remove TATA binding protein (TBP) from DNA. MOT1 function requires a 17 bp DNA 'handle' upstream of the TATA box, which must be double stranded. Remarkably, MOT1-catalyzed disruption of TBP-DNA does not appear to require DNA strand separation, DNA bending or twisting of the DNA helix. Thus, TBP-DNA disruption is accomplished in a reaction apparently not driven by a change in DNA structure. MOT1 action is supported by DNA templates in which the handle is connected to the TATA box via single-stranded DNA, indicating that the upstream duplex DNA can be conformationally uncoupled from the TATA box. Combining these results with proposed similarities between SNF2/SWI2 ATPases and helicases, we suggest that MOT1 uses ATP hydrolysis to translocate along the handle and thereby disrupt interactions between TBP and DNA.
与SNF2/SWI2相关的ATP酶利用ATP水解来破坏蛋白质与DNA的相互作用，但ATP水解如何与这种破坏相偶联尚不清楚。在这里，我们研究了MOT1的作用机制，MOT1是一种与酵母SNF2/SWI2相关的ATP酶，它利用ATP水解从DNA上去除TATA结合蛋白（TBP）。MOT1的功能需要TATA框上游一个17bp的DNA“手柄”，该手柄必须是双链的。值得注意的是，MOT1催化的TBP-DNA破坏似乎不需要DNA链分离、DNA弯曲或DNA螺旋的扭曲。因此，TBP-DNA的破坏是在一个显然不受DNA结构变化驱动的反应中完成的。MOT1的作用得到了DNA模板的支持，在这些模板中，手柄通过单链DNA与TATA框相连，这表明上游双链DNA可以在构象上与TATA框解偶联。将这些结果与SNF2/SWI2 ATP酶和螺旋酶之间的相似性相结合，我们认为MOT1利用ATP水解沿着手柄移位，从而破坏TBP与DNA之间的相互作用。
