3SG4: Crystal Structure Of Gcamp3-d380y, Lp(linker 2)

Genetically encoded calcium indicators (GECIs) are powerful tools for systems neuroscience. Recent efforts in protein engineering have significantly increased the performance of GECIs. The state-of-the art single-wavelength GECI, GCaMP3, has been deployed in a number of model organisms and can reliably detect three or more action potentials in short bursts in several systems in vivo. Through protein structure determination, targeted mutagenesis, high-throughput screening, and a battery of in vitro assays, we have increased the dynamic range of GCaMP3 by severalfold, creating a family of "GCaMP5" sensors. We tested GCaMP5s in several systems: cultured neurons and astrocytes, mouse retina, and in vivo in Caenorhabditis chemosensory neurons, Drosophila larval neuromuscular junction and adult antennal lobe, zebrafish retina and tectum, and mouse visual cortex. Signal-to-noise ratio was improved by at least 2- to 3-fold. In the visual cortex, two GCaMP5 variants detected twice as many visual stimulus-responsive cells as GCaMP3. By combining in vivo imaging with electrophysiology we show that GCaMP5 fluorescence provides a more reliable measure of neuronal activity than its predecessor GCaMP3. GCaMP5 allows more sensitive detection of neural activity in vivo and may find widespread applications for cellular imaging in general.
PDB ID: 3SG4Download
MMDB ID: 100636
PDB Deposition Date: 2011/6/14
Updated in MMDB: 2017/06
Experimental Method:
x-ray diffraction
Resolution: 2.4  Å
Similar Structures:
Biological Unit for 3SG4: monomeric; determined by author and by software (PISA)
Molecular Components in 3SG4
Label Count Molecule
Protein (1 molecule)
Myosin Light Chain Kinase, Green Fluorescent Protein, Calmodulin-1 Chimera(Gene symbol: Calm1)
Molecule annotation
Chemicals (4 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB