MOT1-catalyzed TBP–DNA disruption: uncoupling DNA conformational change and role of upstream DNA

AUTOR(ES)

Darst, Russell P.

FONTE

Oxford University Press

RESUMO

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.

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