STIM1蛋白SOAR结构域与小分子的共结晶及X射线衍射的初步研究

Co-crystallization of SOAR from STIM1 with Small Molecule and Preliminary X-ray Diffraction Analysis

钙库操纵的钙内流(Store-operated Ca2+entry)是钙离子进入细胞的一种经典方式,对于多种细胞生理活动具有重要的意义.它是由位于内质网膜上的钙离子感受器STIM1分子与细胞膜上的通道蛋白ORAI1相互作用而被激活的.其中,STIM1位于细胞质内的C端含有一段SOAR(STIM-ORAI association region)结构域,可以和ORAI1直接作用从而激活ORAI1组成的CRAC通道.考虑到STIM1在钙库操纵的钙内流过程中的重要调节作用,通过药物分子来调节STIM1的活性从而影响细胞、甚至机体的生理活动势必成为关注的方向.本实验将人类STIM1分子的SOAR结构域在大肠杆菌中异源表达,经过多种层析方法获得了纯度较高的SOAR蛋白,并通过与一种小分子——间苯二酚的共结晶,获得了复合物的晶体.X光衍射数据收集到0.21nm,并用HKL2000软件进行处理.这些数据为SOAR与间苯二酚复合物结构的解析奠定了基础.

Store-operated Ca2＋ entry（SOCE）is a classical Ca2＋ signaling pathway,plays an important part in many cellular functions.SOCE is triggered by the interaction of the Ca2＋sensor STIM1 on the ER membrane with ORAI1,the pore-forming unit of the Ca2＋-release activated Ca2＋（CRAC）channel on the plasma membrane.Notably,a domain called STIM-ORAI association region（SOAR）was found to interact directly with ORAI1 to activate the Ca2＋channel.Concerning the critical role for STIM1 in the SOCE process,development of drugs that target STIM1 to control cellular or even the whole organism＇s physiological function must be attractive.Here,SOAR was expressed,purified and co-crystallized with resorcinol.The X-ray diffraction data was collected up to 0.21 nm,and analyzed using HKL2000.These data lend a great support to the structure determination of the SOAR-resorcinol complex.