Structural insight into enhanced calcium indicator GCaMP3 and GCaMPJ to promote further improvement  

作　　者：Yingxiao Chen Xianqiang Song Sheng Ye Lin Miao Yun Zhu Rong-Guang Zhang Guangju Ji 

机构地区：[1]National Laboratory of Biomacromolecules,Institute of Biophysics,Chinese Academy of Sciences,Beijing 100101,China

出　　处：《Protein & Cell》2013年第4期299-309,共11页蛋白质与细胞（英文版）

基　　金：supported by grants from the National Basic Research Program of China(Nos.2011CB8091004 and 2009CB918701)。

摘　　要：Genetically encoded Ca^(2+) indicators(GECI)are important for the measurement of Ca^(2+) in vivo.GCaMP2,a widelyused GECI,has recently been iteratively improved.Among the improved variants,GCaMP3 exhibits significantly better fluorescent intensity.In this study,we developed a new GECI called GCaMPJ and determined the crystal structures of GCaMP3 and GCaMPJ.GCaMPJ has a 1.5-fold increase in fl uorescence and 1.3-fold increase in calcium affi nity over GCaMP3.Upon Ca^(2+) binding,GCaMP3 exhibits both monomeric and dimeric forms.The structural superposition of these two forms reveals the role of Arg-376 in improving monomer performance.However,GCaMPJ seldom forms dimers under conditions similar to GCaMP3.St ructural and mutagenesis studies on Tyr-380 confi rmed its importance in blocking the cpEGFPβ-barrel holes.Our study proposes an efficient tool for mapping Ca^(2+) signals in intact organs to facilitate the further improvement of GCaMP sensors.

关 键 词：genetically encoded calcium indicator mu-tants crystal structure fl uorescentintensity DIMERIZATION 

分 类 号：O63[理学—高分子化学]