3ekj: Difference between revisions
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[[ | ==Calcium-free GCaMP2 (calcium binding deficient mutant)== | ||
<StructureSection load='3ekj' size='340' side='right' caption='[[3ekj]], [[Resolution|resolution]] 2.80Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[3ekj]] is a 1 chain structure with sequence from [http://en.wikipedia.org/wiki/Synthetic_construct Synthetic construct]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3EKJ OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3EKJ FirstGlance]. <br> | |||
</td></tr><tr id='NonStdRes'><td class="sblockLbl"><b>[[Non-Standard_Residue|NonStd Res:]]</b></td><td class="sblockDat"><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='related'><td class="sblockLbl"><b>[[Related_structure|Related:]]</b></td><td class="sblockDat">[[3ek4|3ek4]], [[3ek7|3ek7]], [[3ek8|3ek8]], [[3ekh|3ekh]]</td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=3ekj FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3ekj OCA], [http://www.rcsb.org/pdb/explore.do?structureId=3ekj RCSB], [http://www.ebi.ac.uk/pdbsum/3ekj PDBsum]</span></td></tr> | |||
</table> | |||
<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®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
==See Also== | ==See Also== | ||
*[[Calmodulin|Calmodulin]] | *[[Calmodulin|Calmodulin]] | ||
*[[Green Fluorescent Protein|Green Fluorescent Protein]] | *[[Green Fluorescent Protein|Green Fluorescent Protein]] | ||
== References == | |||
<references/> | |||
__TOC__ | |||
== | </StructureSection> | ||
< | |||
[[Category: Synthetic construct]] | [[Category: Synthetic construct]] | ||
[[Category: Akerboom, J | [[Category: Akerboom, J]] | ||
[[Category: Looger, L L | [[Category: Looger, L L]] | ||
[[Category: Rivera, J D.Velez | [[Category: Rivera, J D.Velez]] | ||
[[Category: Schreiter, E R | [[Category: Schreiter, E R]] | ||
[[Category: Apo gcamp2]] | [[Category: Apo gcamp2]] | ||
[[Category: Calcium-free]] | [[Category: Calcium-free]] | ||
Revision as of 20:21, 21 December 2014
Calcium-free GCaMP2 (calcium binding deficient mutant)Calcium-free GCaMP2 (calcium binding deficient mutant)
Structural highlights
Publication Abstract from PubMedThe 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[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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