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==Crystal Structure of an Apo Green Fluorescent Protein Zn Biosensor== | |||
<StructureSection load='1kyp' size='340' side='right'caption='[[1kyp]], [[Resolution|resolution]] 1.35Å' scene=''> | |||
| | == Structural highlights == | ||
<table><tr><td colspan='2'>[[1kyp]] is a 1 chain structure with sequence from [https://en.wikipedia.org/wiki/Aequorea_victoria Aequorea victoria]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1KYP OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1KYP 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]] 1.35Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CRG:[2-(1-AMINO-2-HYDROXY-PROPYL)-4-(3H-IMIDAZOL-4-YLMETHYLENE)-5-OXO-4,5-DIHYDRO-IMIDAZOL-1-YL]-ACETIC+ACID'>CRG</scene>, <scene name='pdbligand=MG:MAGNESIUM+ION'>MG</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=1kyp FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1kyp OCA], [https://pdbe.org/1kyp PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1kyp RCSB], [https://www.ebi.ac.uk/pdbsum/1kyp PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1kyp ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[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. | |||
== Evolutionary Conservation == | |||
[[Image:Consurf_key_small.gif|200px|right]] | |||
Check<jmol> | |||
<jmolCheckbox> | |||
<scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/ky/1kyp_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked> | |||
<text>to colour the structure by Evolutionary Conservation</text> | |||
</jmolCheckbox> | |||
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=1kyp ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
We designed a green fluorescent protein mutant (BFPms1) that preferentially binds Zn(II) (enhancing fluorescence intensity) and Cu(II) (quenching fluorescence) directly to a chromophore ligand that resembles a dipyrrole unit of a porphyrin. Crystallographic structure determination of apo, Zn(II)-bound, and Cu(II)-bound BFPms1 to better than 1.5 A resolution allowed us to refine metal centers without geometric restraints, to calculate experimental standard uncertainty errors for bond lengths and angles, and to model thermal displacement parameters anisotropically. The BFPms1 Zn(II) site (KD = 50 muM) displays distorted trigonal bipyrimidal geometry, with Zn(II) binding to Glu222, to a water molecule, and tridentate to the chromophore ligand. In contrast, the BFPms1 Cu(II) site (KD = 24 muM) exhibits square planar geometry similar to metalated porphyrins, with Cu(II) binding to the chromophore chelate and Glu222. The apo structure reveals a large electropositive region near the designed metal insertion channel, suggesting a basis for the measured metal cation binding kinetics. The preorganized tridentate ligand is accommodated in both coordination geometries by a 0.4 A difference between the Zn and Cu positions and by distinct rearrangements of Glu222. The highly accurate metal ligand bond lengths reveal different protonation states for the same oxygen bound to Zn vs Cu, with implications for the observed metal ion specificity. Crystallographic anisotropic thermal factor analysis validates metal ion rigidification of the chromophore in enhancement of fluorescence intensity upon Zn(II) binding. Thus, our high-resolution structures reveal how structure-based design has effectively linked selective metal binding to changes in fluorescent properties. Furthermore, this protein Zn(II) biosensor provides a prototype suitable for further optimization by directed evolution to generate metalloprotein variants with desirable physical or biochemical properties. | |||
Structural chemistry of a green fluorescent protein Zn biosensor.,Barondeau DP, Kassmann CJ, Tainer JA, Getzoff ED J Am Chem Soc. 2002 Apr 10;124(14):3522-4. PMID:11929238<ref>PMID:11929238</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1kyp" style="background-color:#fffaf0;"></div> | |||
== | ==See Also== | ||
*[[Green Fluorescent Protein 3D structures|Green Fluorescent Protein 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
== | |||
[[Category: Aequorea victoria]] | [[Category: Aequorea victoria]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Barondeau | [[Category: Barondeau DP]] | ||
[[Category: Getzoff | [[Category: Getzoff ED]] | ||
[[Category: Kassmann | [[Category: Kassmann CJ]] | ||
[[Category: Tainer | [[Category: Tainer JA]] | ||