View source for 4i2y


==Crystal Structure of the genetically encoded calcium indicator RGECO1==
<StructureSection load='4i2y' size='340' side='right'caption='[[4i2y]], [[Resolution|resolution]] 2.20&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4i2y]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Discosoma_sp. Discosoma sp.], [https://en.wikipedia.org/wiki/Gallus_gallus Gallus gallus] and [https://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=4I2Y OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4I2Y 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]] 2.2&#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=NRQ:{(4Z)-4-(4-HYDROXYBENZYLIDENE)-2-[3-(METHYLTHIO)PROPANIMIDOYL]-5-OXO-4,5-DIHYDRO-1H-IMIDAZOL-1-YL}ACETIC+ACID'>NRQ</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=4i2y FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4i2y OCA], [https://pdbe.org/4i2y PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4i2y RCSB], [https://www.ebi.ac.uk/pdbsum/4i2y PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4i2y ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q6LDG3_CHICK Q6LDG3_CHICK] [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/RFP_DISSP RFP_DISSP] Thought to play a role in photoprotection of the coral's resident symbiont microalgae's photosystems from photoinhibition caused by high light levels found near the surface of coral reefs. In deeper water, the fluorescence may be to convert blue light into longer wavelengths more suitable for use in photosynthesis by the microalgal symbionts.<ref>PMID:10504696</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Genetically encoded calcium indicators (GECIs) are powerful tools for systems neuroscience. Here we describe red, single-wavelength GECIs, "RCaMPs," engineered from circular permutation of the thermostable red fluorescent protein mRuby. High-resolution crystal structures of mRuby, the red sensor RCaMP, and the recently published red GECI R-GECO1 give insight into the chromophore environments of the Ca(2+)-bound state of the sensors and the engineered protein domain interfaces of the different indicators. We characterized the biophysical properties and performance of RCaMP sensors in vitro and in vivo in Caenorhabditis elegans, Drosophila larvae, and larval zebrafish. Further, we demonstrate 2-color calcium imaging both within the same cell (registering mitochondrial and somatic [Ca(2+)]) and between two populations of cells: neurons and astrocytes. Finally, we perform integrated optogenetics experiments, wherein neural activation via channelrhodopsin-2 (ChR2) or a red-shifted variant, and activity imaging via RCaMP or GCaMP, are conducted simultaneously, with the ChR2/RCaMP pair providing independently addressable spectral channels. Using this paradigm, we measure calcium responses of naturalistic and ChR2-evoked muscle contractions in vivo in crawling C. elegans. We systematically compare the RCaMP sensors to R-GECO1, in terms of action potential-evoked fluorescence increases in neurons, photobleaching, and photoswitching. R-GECO1 displays higher Ca(2+) affinity and larger dynamic range than RCaMP, but exhibits significant photoactivation with blue and green light, suggesting that integrated channelrhodopsin-based optogenetics using R-GECO1 may be subject to artifact. Finally, we create and test blue, cyan, and yellow variants engineered from GCaMP by rational design. This engineered set of chromatic variants facilitates new experiments in functional imaging and optogenetics.

Genetically encoded calcium indicators for multi-color neural activity imaging and combination with optogenetics.,Akerboom J, Carreras Calderon N, Tian L, Wabnig S, Prigge M, Tolo J, Gordus A, Orger MB, Severi KE, Macklin JJ, Patel R, Pulver SR, Wardill TJ, Fischer E, Schuler C, Chen TW, Sarkisyan KS, Marvin JS, Bargmann CI, Kim DS, Kugler S, Lagnado L, Hegemann P, Gottschalk A, Schreiter ER, Looger LL Front Mol Neurosci. 2013;6:2. doi: 10.3389/fnmol.2013.00002. Epub 2013 Mar 4. PMID:23459413<ref>PMID:23459413</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 4i2y" style="background-color:#fffaf0;"></div>

==See Also==
*[[Green Fluorescent Protein 3D structures|Green Fluorescent Protein 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Discosoma sp]]
[[Category: Gallus gallus]]
[[Category: Large Structures]]
[[Category: Rattus norvegicus]]
[[Category: Akerboom J]]
[[Category: Looger LL]]
[[Category: Schreiter ER]]