The kinase-inducible domain (KIX) of the transcriptional coactivator CBP binds multiple transcriptional regulators through two allosterically connected sites. Establishing a method for observing activator-specific KIX conformations would facilitate the discovery of drug-like molecules that capture specific conformations and further elucidate how distinct activator-KIX complexes produce differential transcriptional effects. However, the transient and low to moderate affinity interactions between activators and KIX are difficult to capture using traditional biophysical assays. Here, we describe a collision-induced unfolding-based approach that produces unique fingerprints for peptides bound to each of the two available sites within KIX, as well as a third fingerprint for ternary KIX complexes. Furthermore, we evaluate the analytical utility of unfolding fingerprints for KIX complexes using CIUSuite, and conclude by speculating as to the structural origins of the conformational families created from KIX:peptide complexes following collisional activation. Graphical Abstract ᅟ.

中文翻译：

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碰撞诱导的展开揭示了KIX调控域中远程蛋白质相互作用位点的独特指纹。

转录共激活因子CBP的激酶诱导结构域（KIX）通过两个变构连接的位点结合多个转录调节因子。建立用于观察活化剂特异性KIX构象的方法将有助于发现捕获特定构象的药物样分子，并进一步阐明不同的活化剂-KIX复合物如何产生差异的转录作用。但是，激活剂和KIX之间的瞬时和低至中等亲和力相互作用很难使用传统的生物物理分析方法来捕获。在这里，我们描述了一种基于碰撞诱导的基于折叠的方法，该方法为结合到KIX内两个可用位点的每一个肽产生独特的指纹，以及为三元KIX配合物生成第三只指纹。此外，我们使用CIUSuite评估了KIX复合物展开指纹的分析实用性，并通过推测碰撞激活后从KIX：肽复合物创建的构象家族的结构起源来得出结论。图形摘要ᅟ。