4IK4 image
Deposition Date 2012-12-25
Release Date 2014-02-05
Last Version Date 2024-10-30
Entry Detail
PDB ID:
4IK4
Title:
High resolution structure of GCaMP3 at pH 5.0
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
2.01 Å
R-Value Free:
0.21
R-Value Work:
0.17
R-Value Observed:
0.17
Space Group:
C 1 2 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:RCaMP, Green fluorescent protein
Gene (Uniprot):GFP
Mutations:M153K, V163A, S175G, D180Y, T203V, A206K, H231L, F64L, V93I, I354T
Chain IDs:A
Chain Length:450
Number of Molecules:1
Biological Source:Entacmaea quadricolor, Aequorea victoria
Modified Residue
Compound ID Chain ID Parent Comp ID Details 2D Image
CRO A GLY ?
Ligand Molecules
Primary Citation
Structural insight into enhanced calcium indicator GCaMP3 and GCaMPJ to promote further improvement.
Protein Cell 4 299 309 (2013)
PMID: 23549615 DOI: 10.1007/s13238-013-2103-4

Abstact

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.

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Primary Citation of related structures