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==Molecular Mechanism of Enantioselective Proton Transfer to Carbon in Catalytic Antibody 14D9== | |||
<StructureSection load='1uwg' size='340' side='right'caption='[[1uwg]], [[Resolution|resolution]] 2.79Å' scene=''> | |||
== Structural highlights == | |||
| | <table><tr><td colspan='2'>[[1uwg]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] and [https://en.wikipedia.org/wiki/Mus_musculus Mus musculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1UWG OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1UWG 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]] 2.79Å</td></tr> | ||
| | <tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=KHA:1-(4-{[(2-HYDROXYETHYL)AMINO]CARBONYL}BENZYL)-1-METHYLPIPERIDINIUM'>KHA</scene>, <scene name='pdbligand=PO4:PHOSPHATE+ION'>PO4</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=1uwg FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1uwg OCA], [https://pdbe.org/1uwg PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1uwg RCSB], [https://www.ebi.ac.uk/pdbsum/1uwg PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1uwg ProSAT]</span></td></tr> | |||
</table> | |||
== 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/uw/1uwg_consurf.spt"</scriptWhenChecked> | |||
<scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=1uwg ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Catalytic antibody 14D9 catalyzes the enantioselective protonation of prochiral enol ethers with high enantioselectivity (>99% ee) and a practical turnover (k(cat) = 0.4 s(-1)), allowing for preparative scale applications. This antibody represents one of the rare examples of catalytic antibodies promoting acid-catalyzed processes. Antibody 14D9 was cloned and expressed as a chimeric Fab fragment in Escherichia coli. Crystal structures of Fab 14D9 as apo form and of its close analog 19C9 in complex with the transition state analog were determined at 2.8-A resolution. A series of site-directed mutagenesis experiments was carried out to probe the role of individual active-site amino acids. Proton transfer to carbon is catalyzed by a hydrogen bond network formed by the side chains of Asp(H101) and Tyr(L36) with a water molecule serving as a relay. The intermediate oxocarbonium ion formed during the protonation step is trapped by the same water molecule, resulting in an overall syn-addition of water to the enol ether's double bond. The enantioselectivity is caused by steric crowding at the active site, mainly because of the side chain of Phe(H84). The 20-fold lower activity of 19C9 compared with 14D9 was traced down to residue Thr(L46), which forms a nonproductive hydrogen bond with the catalytic residue Asp(H101), which competes with the critical Asp(H101)-Tyr(L36) hydrogen bond and therefore reduces catalytic efficiency. The catalytic activity of 19C9 was restored to that of 14D9 by using either site-directed mutagenesis (Thr(L46)Ala) or chain shuffling. | |||
Molecular mechanism of enantioselective proton transfer to carbon in catalytic antibody 14D9.,Zheng L, Baumann U, Reymond JL Proc Natl Acad Sci U S A. 2004 Mar 9;101(10):3387-92. Epub 2004 Feb 26. PMID:14988504<ref>PMID:14988504</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 1uwg" style="background-color:#fffaf0;"></div> | |||
== | ==See Also== | ||
*[[Monoclonal Antibodies 3D structures|Monoclonal Antibodies 3D structures]] | |||
== References == | |||
<references/> | |||
[[Category: | __TOC__ | ||
[[Category: | </StructureSection> | ||
[[Category: | [[Category: Homo sapiens]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: | [[Category: Mus musculus]] | ||
[[Category: Baumann U]] | |||
[[Category: Reymond JL]] | |||
Latest revision as of 03:35, 21 November 2024
Molecular Mechanism of Enantioselective Proton Transfer to Carbon in Catalytic Antibody 14D9Molecular Mechanism of Enantioselective Proton Transfer to Carbon in Catalytic Antibody 14D9
Structural highlights
Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCatalytic antibody 14D9 catalyzes the enantioselective protonation of prochiral enol ethers with high enantioselectivity (>99% ee) and a practical turnover (k(cat) = 0.4 s(-1)), allowing for preparative scale applications. This antibody represents one of the rare examples of catalytic antibodies promoting acid-catalyzed processes. Antibody 14D9 was cloned and expressed as a chimeric Fab fragment in Escherichia coli. Crystal structures of Fab 14D9 as apo form and of its close analog 19C9 in complex with the transition state analog were determined at 2.8-A resolution. A series of site-directed mutagenesis experiments was carried out to probe the role of individual active-site amino acids. Proton transfer to carbon is catalyzed by a hydrogen bond network formed by the side chains of Asp(H101) and Tyr(L36) with a water molecule serving as a relay. The intermediate oxocarbonium ion formed during the protonation step is trapped by the same water molecule, resulting in an overall syn-addition of water to the enol ether's double bond. The enantioselectivity is caused by steric crowding at the active site, mainly because of the side chain of Phe(H84). The 20-fold lower activity of 19C9 compared with 14D9 was traced down to residue Thr(L46), which forms a nonproductive hydrogen bond with the catalytic residue Asp(H101), which competes with the critical Asp(H101)-Tyr(L36) hydrogen bond and therefore reduces catalytic efficiency. The catalytic activity of 19C9 was restored to that of 14D9 by using either site-directed mutagenesis (Thr(L46)Ala) or chain shuffling. Molecular mechanism of enantioselective proton transfer to carbon in catalytic antibody 14D9.,Zheng L, Baumann U, Reymond JL Proc Natl Acad Sci U S A. 2004 Mar 9;101(10):3387-92. Epub 2004 Feb 26. PMID:14988504[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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