Department of Biochemistry, University of Cambridge, Cambridge CB2 1GA, U.K.
Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States.
J Med Chem. 2020 Nov 12;63(21):12786-12798. doi: 10.1021/acs.jmedchem.0c01173. Epub 2020 Oct 29.
CK2α is a ubiquitous, well-studied kinase that is a target for small-molecule inhibition, for treatment of cancers. While many different classes of adenosine 5'-triphosphate (ATP)-competitive inhibitors have been described for CK2α, they tend to suffer from significant off-target activity and new approaches are needed. A series of inhibitors of CK2α has recently been described as allosteric, acting at a previously unidentified binding site. Given the similarity of these inhibitors to known ATP-competitive inhibitors, we have investigated them further. In our thorough structural and biophysical analyses, we have found no evidence that these inhibitors bind to the proposed allosteric site. Rather, we report crystal structures, competitive isothermal titration calorimetry (ITC) and NMR, hydrogen-deuterium exchange (HDX) mass spectrometry, and chemoinformatic analyses that all point to these compounds binding in the ATP pocket. Comparisons of our results and experimental approach with the data presented in the original report suggest that the primary reason for the disparity is nonspecific inhibition by aggregation.
CK2α 是一种普遍存在且研究充分的激酶，是小分子抑制的靶点，可用于治疗癌症。虽然已经描述了许多不同类别的腺苷 5'-三磷酸 (ATP) 竞争性抑制剂用于 CK2α，但它们往往存在显著的脱靶活性，需要新的方法。最近描述了一系列 CK2α 的抑制剂为别构抑制剂，作用于先前未确定的结合位点。鉴于这些抑制剂与已知的 ATP 竞争性抑制剂相似，我们对它们进行了进一步研究。在我们全面的结构和生物物理分析中，我们没有发现这些抑制剂与所提出的变构位点结合的证据。相反，我们报告了晶体结构、竞争等温滴定量热法 (ITC) 和 NMR、氢氘交换 (HDX) 质谱和计算化学分析，所有这些都表明这些化合物结合在 ATP 口袋中。我们的结果和实验方法与原始报告中提出的数据进行比较，表明差异的主要原因是非特异性聚集抑制。
