Dissecting allosteric effects of activator-coactivator complexes using a covalent small molecule ligand.
Dissecting allosteric effects of activator-coactivator complexes using a covalent small molecule ligand.
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使用共价小分子配体剖析激活剂-共激活剂复合物的变构效应。
DOI：
10.1073/pnas.1406033111
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发表时间：
2014
影响因子：
11.1
通讯作者：
Mapp,AnnaK
中科院分区：
文献类型：
--
作者：
Wang,Ningkun;Lodge,JeanM;Fierke,CarolA;Mapp,AnnaK
变构结合事件在转录激活因子-辅激活因子复合物的形成和稳定性中起着至关重要的作用，部分原因可能是由于一个或多个组成伙伴的内在无序性。主辅激活因子CREB结合蛋白/p300的激酶诱导结构域相互作用（KIX）结构域是一个构象动态结构域，在变构通信中与转录激活因子在两个离散的结合位点复合。KIX与混合谱系白血病蛋白的转录激活结构域的络合导致CREB激活结构域（CREB的磷酸化激酶诱导结构域）与第二位点的结合增强。由小分子配体诱导正或负协同结合的三元配合物形成的瞬态动力学分析表明，正协同性在很大程度上取决于结合物的稳定性，如油墨减少所表明的那样。因此，这表明对第二配体的结合亲和力的增加不是由于第一配体产生更有利的结合界面的变构性。这与我们和其他人的数据一致，表明构象动态蛋白质的速率接近扩散极限。相反，负协同性表现为双konandkoff的改变，表明二元配合物的稳定性。
Allosteric binding events play a critical role in the formation and stability of transcriptional activator–coactivator complexes, perhaps in part due to the often intrinsically disordered nature of one or more of the constituent partners. The kinase-inducible domain interacting (KIX) domain of the master coactivator CREB binding protein/p300 is a conformationally dynamic domain that complexes with transcriptional activators at two discrete binding sites in allosteric communication. The complexation of KIX with the transcriptional activation domain of mixed-lineage leukemia protein leads to an enhancement of binding by the activation domain of CREB (phosphorylated kinase-inducible domain of CREB) to the second site. A transient kinetic analysis of the ternary complex formation aided by small molecule ligands that induce positive or negative cooperative binding reveals that positive cooperativity is largely governed by stabilization of the bound complex as indicated by a decrease inkoff. Thus, this suggests the increased binding affinity for the second ligand is not due to an allosteric creation of a more favorable binding interface by the first ligand. This is consistent with data from us and from others indicating that the on rates of conformationally dynamic proteins approach the limits of diffusion. In contrast, negative cooperativity is manifested by alterations in bothkonandkoff, suggesting stabilization of the binary complex.