School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K.
School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K.
J Med Chem. 2021 Apr 8;64(7):3813-3826. doi: 10.1021/acs.jmedchem.0c01944. Epub 2021 Mar 16.
Src homology 2 domain-containing inositol phosphate phosphatase 2 (SHIP2) is one of the 10 human inositol phosphate 5-phosphatases. One of its physiological functions is dephosphorylation of phosphatidylinositol 3,4,5-trisphosphate, PtdIns(3,4,5)P. It is therefore a therapeutic target for pathophysiologies dependent on PtdIns(3,4,5)P and PtdIns(3,4)P. Therapeutic interventions are limited by the dearth of crystallographic data describing ligand/inhibitor binding. An active site-directed fluorescent probe facilitated screening of compound libraries for SHIP2 ligands. With two additional orthogonal assays, several ligands including galloflavin were identified as low micromolar Ki inhibitors. One ligand, an oxo-linked ethylene-bridged dimer of benzene 1,2,4-trisphosphate, was shown to be an uncompetitive inhibitor that binds to a regulatory site on the catalytic domain. We posit that binding of ligands to this site restrains L4 loop motions that are key to interdomain communications that accompany high catalytic activity with phosphoinositide substrate. This site may, therefore, be a future druggable target for medicinal chemistry.
Src 同源 2 结构域内含肌醇磷酸磷酸酶 2（SHIP2）是人类肌醇 5-磷酸酶的 10 种之一。其生理功能之一是使磷脂酰肌醇 3,4,5-三磷酸（PtdIns（3,4,5）P）去磷酸化。因此，它是依赖 PtdIns（3,4,5）P 和 PtdIns（3,4）P 的病理生理的治疗靶点。由于缺乏描述配体/抑制剂结合的晶体学数据，治疗干预受到限制。一个活性位点定向荧光探针促进了 SHIP2 配体的化合物库筛选。通过另外两个正交测定法，鉴定了几种配体，包括金缕梅黄素，它们是低微摩尔 Ki 抑制剂。一种配体，苯 1,2,4-三磷酸的氧桥联乙烯桥联二聚体，被证明是一种非竞争性抑制剂，它结合在催化结构域的调节位点上。我们假设，配体与该位点的结合限制了 L4 环的运动，该运动对于伴随磷酸肌醇底物高催化活性的结构域间通讯至关重要。因此，该位点可能是药物化学的未来可药用靶标。
