View source for 3ek7


==Calcium-saturated GCaMP2 dimer==
<StructureSection load='3ek7' size='340' side='right'caption='[[3ek7]], [[Resolution|resolution]] 1.85&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[3ek7]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Aequorea_victoria Aequorea victoria], [https://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] and [https://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3EK7 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3EK7 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 1.85&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CA:CALCIUM+ION'>CA</scene>, <scene name='pdbligand=CRO:{2-[(1R,2R)-1-AMINO-2-HYDROXYPROPYL]-4-(4-HYDROXYBENZYLIDENE)-5-OXO-4,5-DIHYDRO-1H-IMIDAZOL-1-YL}ACETIC+ACID'>CRO</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=3ek7 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ek7 OCA], [https://pdbe.org/3ek7 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3ek7 RCSB], [https://www.ebi.ac.uk/pdbsum/3ek7 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3ek7 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CALM1_RAT CALM1_RAT] Calmodulin mediates the control of a large number of enzymes, ion channels, aquaporins and other proteins through calcium-binding. Among the enzymes to be stimulated by the calmodulin-calcium complex are a number of protein kinases and phosphatases. Together with CCP110 and centrin, is involved in a genetic pathway that regulates the centrosome cycle and progression through cytokinesis. Mediates calcium-dependent inactivation of CACNA1C. Positively regulates calcium-activated potassium channel activity of KCNN2.[UniProtKB:P62158][https://www.uniprot.org/uniprot/MYLK_CHICK MYLK_CHICK] Phosphorylates a specific serine in the N-terminus of a myosin light chain, which leads to the formation of calmodulin/MLCK signal transduction complexes which allow selective transduction of calcium signals.[https://www.uniprot.org/uniprot/GFP_AEQVI GFP_AEQVI] Energy-transfer acceptor. Its role is to transduce the blue chemiluminescence of the protein aequorin into green fluorescent light by energy transfer. Fluoresces in vivo upon receiving energy from the Ca(2+)-activated photoprotein aequorin.
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
The genetically encoded calcium indicator GCaMP2 shows promise for neural network activity imaging, but is currently limited by low signal-to-noise ratio. We describe x-ray crystal structures as well as solution biophysical and spectroscopic characterization of GCaMP2 in the calcium-free dark state, and in two calcium-bound bright states: a monomeric form that dominates at intracellular concentrations observed during imaging experiments and an unexpected domain-swapped dimer with decreased fluorescence. This series of structures provides insight into the mechanism of Ca(2+)-induced fluorescence change. Upon calcium binding, the calmodulin (CaM) domain wraps around the M13 peptide, creating a new domain interface between CaM and the circularly permuted enhanced green fluorescent protein domain. Residues from CaM alter the chemical environment of the circularly permuted enhanced green fluorescent protein chromophore and, together with flexible inter-domain linkers, block solvent access to the chromophore. Guided by the crystal structures, we engineered a series of GCaMP2 point mutants to probe the mechanism of GCaMP2 function and characterized one mutant with significantly improved signal-to-noise. The mutation is located at a domain interface and its effect on sensor function could not have been predicted in the absence of structural data.

Crystal Structures of the GCaMP Calcium Sensor Reveal the Mechanism of Fluorescence Signal Change and Aid Rational Design.,Akerboom J, Rivera JD, Guilbe MM, Malave EC, Hernandez HH, Tian L, Hires SA, Marvin JS, Looger LL, Schreiter ER J Biol Chem. 2009 Mar 6;284(10):6455-64. Epub 2008 Dec 18. PMID:19098007<ref>PMID:19098007</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 3ek7" style="background-color:#fffaf0;"></div>

==See Also==
*[[Calmodulin 3D structures|Calmodulin 3D structures]]
*[[Green Fluorescent Protein 3D structures|Green Fluorescent Protein 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Aequorea victoria]]
[[Category: Large Structures]]
[[Category: Rattus norvegicus]]
[[Category: Synthetic construct]]
[[Category: Akerboom J]]
[[Category: Looger LL]]
[[Category: Schreiter ER]]
[[Category: Velez Rivera JD]]