4IK1

High resolution structure of GCaMPJ at pH 8.5

Summary for 4IK1

• Entry DOI: 10.2210/pdb4ik1/pdb
• Related: 4IK3 4IK4 4IK5 4IK8 4IK9
• Descriptor: RCaMP, Green fluorescent protein, CALCIUM ION (3 entities in total)
• Functional Keywords: calcium indicator, fluorescent intensity, dimerization, beta barrel, calmodulin, fluorescent protein
• Biological source: Entacmaea quadricolor (Bubble-tip anemone); More
• Total number of polymer chains: 1
• Total formula weight: 50752.79

Authors

Chen, Y.,Song, X.,Miao, L.,Zhu, Y.,Ji, G. (deposition date: 2012-12-25, release date: 2014-02-05, Last modification date: 2017-06-21)

Primary citation

Chen, Y.,Song, X.,Ye, S.,Miao, L.,Zhu, Y.,Zhang, R.G.,Ji, G.
Structural insight into enhanced calcium indicator GCaMP3 and GCaMPJ to promote further improvement.
Protein Cell, 4:299-309, 2013

PubMed 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.

PubMed: 23549615
DOI: 10.1007/s13238-013-2103-4

Experimental method

X-RAY DIFFRACTION (2 Å)