4IK8
High resolution structure of GCaMP3 dimer form 1 at pH 7.5
Summary for 4IK8
Entry DOI | 10.2210/pdb4ik8/pdb |
Related | 4IK1 4IK3 4IK4 4IK5 4IK9 |
Descriptor | RCaMP, Green fluorescent protein, CALCIUM ION (3 entities in total) |
Functional Keywords | calcium indicator, mutants, 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 | 50704.70 |
Authors | |
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 Cited by 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: 23549615DOI: 10.1007/s13238-013-2103-4 PDB entries with the same primary citation |
Experimental method | X-RAY DIFFRACTION (1.55 Å) |
Structure validation
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