Molecular analysis of the SNF2/SWI2 protein family member MOT1, an ATP-driven enzyme that dissociates TATA-binding protein from DNA
Molecular analysis of the SNF2/SWI2 protein family member MOT1, an ATP-driven enzyme that dissociates TATA-binding protein from DNA
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DOI：
10.1128/mcb.17.8.4842
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发表时间：
1997-08-01
影响因子：
5.3
通讯作者：
Hahn, S
中科院分区：
文献类型：
--
作者：
Auble, DT;Wang, DY;Hahn, S
MOT 1是酿酒酵母的一种必需蛋白，也是ATP酶SNF 2/SWI 2家族的成员。MOT 1通过从DNA中去除TATA结合蛋白（TBP）来发挥作用，因此，MOT 1可以在体外和体内调节转录。在这里，我们描述了MOT 1缺失和取代突变体的体内和体外活性。结果表明，MOT 1在体外和体内均通过其非保守N末端的氨基酸靶向TBP。保守的C-末端ATP酶的MOT 1似乎有助于TBP-DNA复合物的识别在ATP的情况下，但它似乎主要在实际的ATP依赖性解离反应。其中SNF 2/SWI 2的同源部分已经取代MOT 1 ATP酶的嵌合蛋白可以结合TBP-DNA复合物，但在ATP存在下不能解离这些复合物，这表明MOT 1的作用特异性也由C-末端ATP酶赋予。ATP酶分析表明，MOT 1 ATP酶被TBP激活。因此，MOT 1经历至少两种构象变化：（i）TBP的变构效应，其介导MOT 1 ATP酶的活化;和（ii）ATP驱动的“动力冲程”，其导致TBP-DNA复合物解离。这些结果为理解SNF 2/SWI 2蛋白家族成员如何使用ATP调节蛋白质-DNA相互作用以调节细胞中的许多不同过程提供了一个总体框架。
MOT1 is an essential Saccharomyces cerevisiae protein and a member of the SNF2/SWI2 family of ATPases. MOT1 functions by removing TATA-binding protein (TBP) from DNA, and as a consequence, MOT1 can regulate transcription both in vitro and in vivo. Here we describe the in vivo and in vitro activities of MOT1 deletion and substitution mutants. The results indicate that MOT1 is targeted to TBP both in vitro and in vivo via amino acids in its nonconserved N terminus. The conserved C-terminal ATPase of MOT1 appears to contribute to TBP-DNA complex recognition in the absence of ATP, but it appears to function primarily during the actual ATP-dependent dissociation reaction. Chimeric proteins in which homologous portions of SNF2/SWI2 have been substituted for the MOT1 ATPase can bind to TBP-DNA complexes but fail to dissociate these complexes in the presence of ATP, suggesting that the specificity of action of MOT1 is also conferred by the C-terminal ATPase. ATPase assays demonstrate that the MOT1 ATPase is activated by TBP. Thus, MOT1 undergoes at least two conformational changes: (i) an allosteric effect of TBP that mediates the activation of the MOT1 ATPase and (ii) an ATP-driven ''power stroke'' that causes TBP-DNA complex dissociation. These results provide a general framework for understanding how members of the SNF2/SWI2 protein family use ATP to modulate protein-DNA interactions to regulate many diverse processes in cells.