7sen: Difference between revisions
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The | ==Crystal structure of Fab containing a fluorescent noncanonical amino acid with blocked excited state proton transfer== | ||
<StructureSection load='7sen' size='340' side='right'caption='[[7sen]], [[Resolution|resolution]] 2.09Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[7sen]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7SEN OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7SEN 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]] 2.09Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=DV7:(2S)-2-amino-4-(7-hydroxy-2-oxo-2H-1-benzopyran-4-yl)butanoic+acid'>DV7</scene>, <scene name='pdbligand=PCA:PYROGLUTAMIC+ACID'>PCA</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=7sen FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=7sen OCA], [https://pdbe.org/7sen PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=7sen RCSB], [https://www.ebi.ac.uk/pdbsum/7sen PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=7sen ProSAT]</span></td></tr> | |||
</table> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
The fluorescent non-canonical amino acid (fNCAA) L-(7-hydroxycoumarin-4-yl)ethylglycine (7-HCAA) contains a photoacidic 7-hydroxycoumarin (7-HC) side chain whose fluorescence properties can be tuned by its environment. In proteins, many alterations to 7-HCAA's fluorescence spectra have been reported including increases and decreases in intensity and red- and blue-shifted emission maxima. The ability to rationally design protein environments that alter 7-HCAA's fluorescence properties in predictable ways could lead to novel protein-based sensors of biological function. However, these efforts are likely limited by a lack of structural characterization of 7-HCAA-containing proteins. Here, we report the steady-state spectroscopic and x-ray crystallographic characterization of a 7-HCAA-containing antibody fragment (in the apo and antigen-bound forms) in which a substantially blue-shifted 7-HCAA emission maximum ( approximately 70 nm) is observed relative to the free amino acid. Our structural characterization of these proteins provides evidence that the blue shift is a consequence of the fact that excited state proton transfer (ESPT) from the 7-HC phenol has been almost completely blocked by interactions with the protein backbone. Furthermore, a direct interaction between a residue in the antigen and the fluorophore served to further block proton transfer relative to the apoprotein. The structural basis of the unprecedented blue shift in 7-HCAA emission reported here provides a framework for the development of new fluorescent protein-based sensors. | |||
Structural Basis for Blocked Excited State Proton Transfer in a Fluorescent, Photoacidic Non-Canonical Amino Acid-Containing Antibody Fragment.,Henderson JN, Simmons CR, Mills JH J Mol Biol. 2022 Apr 30;434(8):167455. doi: 10.1016/j.jmb.2022.167455. Epub 2022 , Jan 13. PMID:35033559<ref>PMID:35033559</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
[[Category: | </div> | ||
[[Category: | <div class="pdbe-citations 7sen" style="background-color:#fffaf0;"></div> | ||
[[Category: Mills | |||
[[Category: | ==See Also== | ||
*[[Antibody 3D structures|Antibody 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Homo sapiens]] | |||
[[Category: Large Structures]] | |||
[[Category: Henderson JN]] | |||
[[Category: Mills JH]] | |||
[[Category: Simmons CR]] | |||
Latest revision as of 12:10, 17 October 2024
Crystal structure of Fab containing a fluorescent noncanonical amino acid with blocked excited state proton transferCrystal structure of Fab containing a fluorescent noncanonical amino acid with blocked excited state proton transfer
Structural highlights
Publication Abstract from PubMedThe fluorescent non-canonical amino acid (fNCAA) L-(7-hydroxycoumarin-4-yl)ethylglycine (7-HCAA) contains a photoacidic 7-hydroxycoumarin (7-HC) side chain whose fluorescence properties can be tuned by its environment. In proteins, many alterations to 7-HCAA's fluorescence spectra have been reported including increases and decreases in intensity and red- and blue-shifted emission maxima. The ability to rationally design protein environments that alter 7-HCAA's fluorescence properties in predictable ways could lead to novel protein-based sensors of biological function. However, these efforts are likely limited by a lack of structural characterization of 7-HCAA-containing proteins. Here, we report the steady-state spectroscopic and x-ray crystallographic characterization of a 7-HCAA-containing antibody fragment (in the apo and antigen-bound forms) in which a substantially blue-shifted 7-HCAA emission maximum ( approximately 70 nm) is observed relative to the free amino acid. Our structural characterization of these proteins provides evidence that the blue shift is a consequence of the fact that excited state proton transfer (ESPT) from the 7-HC phenol has been almost completely blocked by interactions with the protein backbone. Furthermore, a direct interaction between a residue in the antigen and the fluorophore served to further block proton transfer relative to the apoprotein. The structural basis of the unprecedented blue shift in 7-HCAA emission reported here provides a framework for the development of new fluorescent protein-based sensors. Structural Basis for Blocked Excited State Proton Transfer in a Fluorescent, Photoacidic Non-Canonical Amino Acid-Containing Antibody Fragment.,Henderson JN, Simmons CR, Mills JH J Mol Biol. 2022 Apr 30;434(8):167455. doi: 10.1016/j.jmb.2022.167455. Epub 2022 , Jan 13. PMID:35033559[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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