The stress-activated kinase p38α was used to evaluate a fragment-based drug discovery approach using the BioFocus fragment library. Compounds were screened by surface plasmon resonance (SPR) on a Biacore™ T100 against p38α and two selectivity targets. A sub-set of our library was the focus of detailed follow-up analyses that included hit confirmation, affinity determination on 24 confirmed, selective hits and competition assays of these hits with respect to a known ATP binding site inhibitor. In addition, functional activity against p38α was assessed in a biochemical assay using a mobility shift platform (LC3000, Caliper LifeSciences). A selection of fragments was also evaluated using fluorescence lifetime (FLEXYTE™) and microscale thermophoresis (Nanotemper) technologies. A good correlation between the data for the different assays was found. Crystal structures were solved for four of the small molecules complexed to p38α. Interestingly, as determined both by X-ray analysis and SPR competition experiments, three of the complexes involved the fragment at the ATP binding site, while the fourth compound bound in a distal site that may offer potential as a novel drug target site. A first round of optimization around the remotely bound fragment has led to the identification of a series of triazole-containing compounds. This approach could form the basis for developing novel and active p38α inhibitors. More broadly, it illustrates the power of combining a range of biophysical and biochemical techniques to the discovery of fragments that facilitate the development of novel modulators of kinase and other drug targets.
利用 BioFocus 片段库评估了一种基于片段的药物发现方法,即应激活化激酶 p38α。在 Biacore™ T100 上通过表面等离子体共振 (
SPR) 针对 p38α 和两个选择性目标筛选化合物。我们对文库中的一个子集进行了详细的后续分析,包括对 24 个已确认的选择性命中物进行命中确认、亲和力测定,以及这些命中物与已知
ATP 结合位点
抑制剂的竞争分析。此外,还使用迁移率平台(LC3000,Caliper LifeSciences)在生化试验中评估了针对 p38α 的功能活性。还利用荧光寿命(FLEXYTE™)和微尺度热电泳(Nanotemper)技术对部分片段进行了评估。不同检测方法的数据之间具有良好的相关性。解决了四种小分子与 p38α 复合物的晶体结构问题。有趣的是,通过 X 射线分析和
SPR 竞争实验确定,其中三个复合物涉及
ATP 结合位点上的片段,而第四个化合物则结合在一个远端位点上,该位点有可能成为新型药物的靶点。围绕远程结合位点片段进行的第一轮优化,确定了一系列含三唑的化合物。这种方法可作为开发新型活性 p38α
抑制剂的基础。更广泛地说,它说明了结合一系列
生物物理和
生物化学技术发现片段的威力,这些片段有助于开发激酶和其他药物靶点的新型调节剂。