View source for 4ka9


==Crystal structure analysis of single amino acid deletion mutations in EGFP==
<StructureSection load='4ka9' size='340' side='right'caption='[[4ka9]], [[Resolution|resolution]] 1.58&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[4ka9]] 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=4KA9 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=4KA9 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]] 1.58&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><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>, <scene name='pdbligand=EDO:1,2-ETHANEDIOL'>EDO</scene>, <scene name='pdbligand=EPE:4-(2-HYDROXYETHYL)-1-PIPERAZINE+ETHANESULFONIC+ACID'>EPE</scene>, <scene name='pdbligand=NA:SODIUM+ION'>NA</scene>, <scene name='pdbligand=ZN:ZINC+ION'>ZN</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=4ka9 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=4ka9 OCA], [https://pdbe.org/4ka9 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=4ka9 RCSB], [https://www.ebi.ac.uk/pdbsum/4ka9 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=4ka9 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.
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== Publication Abstract from PubMed ==
Altering a protein's backbone through amino acid deletion is a common evolutionary mutational mechanism, but is generally ignored during protein engineering primarily because its effect on the folding-structure-function relationship is difficult to predict. Using directed evolution, enhanced green fluorescent protein (EGFP) was observed to tolerate residue deletion across the breadth of the protein, particularly within short and long loops, helical elements, and at the termini of strands. A variant with G4 removed from a helix (EGFP(G4Delta)) conferred significantly higher cellular fluorescence. Folding analysis revealed that EGFP(G4Delta) retained more structure upon unfolding and refolded with almost 100% efficiency but at the expense of thermodynamic stability. The EGFP(G4Delta) structure revealed that G4 deletion caused a beneficial helical registry shift resulting in a new polar interaction network, which potentially stabilizes a cis proline peptide bond and links secondary structure elements. Thus, deletion mutations and registry shifts can enhance proteins through structural rearrangements not possible by substitution mutations alone.

Random single amino acid deletion sampling unveils structural tolerance and the benefits of helical registry shift on GFP folding and structure.,Arpino JA, Reddington SC, Halliwell LM, Rizkallah PJ, Jones DD Structure. 2014 Jun 10;22(6):889-98. doi: 10.1016/j.str.2014.03.014. Epub 2014, May 22. PMID:24856363<ref>PMID:24856363</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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<div class="pdbe-citations 4ka9" style="background-color:#fffaf0;"></div>

==See Also==
*[[Green Fluorescent Protein 3D structures|Green Fluorescent Protein 3D structures]]
== References ==
<references/>
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</StructureSection>
[[Category: Aequorea victoria]]
[[Category: Large Structures]]
[[Category: Arpino JAJ]]
[[Category: Rizkallah PJ]]