Structure-based design, synthesis and crystallization of 2-arylquinazolines as lipid pocket ligands of p38α MAPK

In protein kinase research, identifying and addressing small molecule binding sites other than the highly conserved ATP-pocket are of intense interest because this line of investigation extends our understanding of kinase function beyond the catalytic phosphotransfer. Such alternative binding sites may be involved in altering the activation state through subtle conformational changes, control cellular enzyme localization, or in mediating and disrupting protein-protein interactions. Small organic molecules that target these less conserved regions might serve as tools for chemical biology research and to probe alternative strategies in targeting protein kinases in disease settings. Here, we present the structure-based design and synthesis of a focused library of 2-arylquinazoline derivatives to target the lipophilic C-terminal binding pocket in p38α MAPK, for which a clear biological function has yet to be identified. The interactions of the ligands with p38α MAPK was analyzed by SPR measurements and validated by protein X-ray crystallography.

在蛋白激酶（protein kinase）研究领域，识别并靶向除高度保守的ATP结合口袋（ATP-pocket）之外的小分子结合位点是当前的研究热点，此类研究可拓展我们对激酶功能超出催化磷酸转移过程的认知。此类可变结合位点（alternative binding sites）可能通过细微的构象变化（conformational changes）调控激酶的激活状态、控制酶在细胞内的定位（cellular enzyme localization），或是介导与阻断蛋白质-蛋白质相互作用（protein-protein interactions）。靶向这些保守性较弱区域的小分子有机化合物（small organic molecules），可作为化学生物学研究（chemical biology research）的工具，同时也为疾病状态下靶向蛋白激酶提供了全新策略。本研究报道了一类基于结构设计（structure-based design）与合成的2-芳基喹唑啉衍生物（2-arylquinazoline derivatives）聚焦文库，用于靶向p38α丝裂原活化蛋白激酶（p38α MAPK）中的亲脂性C端结合口袋（lipophilic C-terminal binding pocket）——该口袋的明确生物学功能目前尚未阐明。我们通过表面等离子体共振（SPR，surface plasmon resonance）测量分析了配体与p38α MAPK的相互作用，并通过蛋白质X射线晶体学（protein X-ray crystallography）验证了结合模式。