Structural insight into enhanced calcium indicator GCaMP3 and GCaMPJ to promote further improvement.
10.1007/s13238-013-2103-4
- Author:
Yingxiao CHEN
1
;
Xianqiang SONG
;
Sheng YE
;
Lin MIAO
;
Yun ZHU
;
Rong-Guang ZHANG
;
Guangju JI
Author Information
1. National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
- Publication Type:Journal Article
- MeSH:
Calcium;
chemistry;
metabolism;
Calmodulin;
chemistry;
genetics;
metabolism;
Crystallography, X-Ray;
Dimerization;
Green Fluorescent Proteins;
chemistry;
genetics;
metabolism;
Histidine;
chemistry;
genetics;
metabolism;
Hydrogen-Ion Concentration;
Myosin-Light-Chain Kinase;
chemistry;
genetics;
metabolism;
Peptide Fragments;
chemistry;
genetics;
metabolism;
Protein Structure, Tertiary;
Recombinant Fusion Proteins;
biosynthesis;
chemistry;
genetics
- From:
Protein & Cell
2013;4(4):299-309
- CountryChina
- Language:English
-
Abstract:
Genetically encoded Ca(2+) indicators (GECI) are important for the measurement of Ca(2+) in vivo. GCaMP2, a widely-used 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 fluorescence and 1.3-fold increase in calcium affinity 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 confirmed its importance in blocking the cpEGFP β-barrel holes. Our study proposes an efficient tool for mapping Ca(2+) signals in intact organs to facilitate the further improvement of GCaMP sensors.
