PDBsum entry 4ik9

Fluorescent protein

PDB id: 4ik9

Contents

Protein chain

394 a.a.

Ligands

PEG

Metals

_CA ×4

Waters ×465

PDB id:

4ik9

Name:

Fluorescent protein

Title:

High resolution structure of gcamp3 dimer form 2 at ph 7.5

Structure:

Rcamp, green fluorescent protein. Chain: a. Engineered: yes. Mutation: yes. Other_details: chimera of 10 expression tags, residues 1-48 of rcamp, linker le, residues 149-238 of green fluorescent protein, linker ggtggsmv, residues 2-144 of green fluorescent protein, residues 284- 432 of rcamp

Source:

Entacmaea quadricolor, aequorea victoria. Bubble-tip anemone, jellyfish. Organism_taxid: 6118, 6100. Gene: gfp. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

1.80Å R-factor: 0.161 R-free: 0.195

Authors:

Y.Chen,X.Song,L.Miao,Y.Zhu,G.Ji

Key ref:

Y.Chen et al. (2013). Structural insight into enhanced calcium indicator GCaMP3 and GCaMPJ to promote further improvement. Protein Cell, 4, 299-309. PubMed id: 23549615 DOI: 10.1007/s13238-013-2103-4

Date:

25-Dec-12 Release date: 29-Jan-14

Protein chain

K4DIE3  (K4DIE3_ENTQU) -  RCaMP from Entacmaea quadricolor

Seq: 432 a.a.

Struc: 394 a.a.*

Protein chain

P42212  (GFP_AEQVI) -  Green fluorescent protein from Aequorea victoria

Seq: 238 a.a.

Struc: 394 a.a.*

* PDB and UniProt seqs differ at 262 residue positions (black crosses)

DOI no: 10.1007/s13238-013-2103-4

Protein Cell 4:299-309 (2013)

PubMed id: 23549615

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

Y.Chen, X.Song, S.Ye, L.Miao, Y.Zhu, R.G.Zhang, G.Ji.

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.