6c71: Difference between revisions
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<StructureSection load='6c71' size='340' side='right' caption='[[6c71]], [[Resolution|resolution]] 2.65Å' scene=''> | <StructureSection load='6c71' size='340' side='right' caption='[[6c71]], [[Resolution|resolution]] 2.65Å' scene=''> | ||
== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>[[6c71]] is a 4 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6C71 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6C71 FirstGlance]. <br> | <table><tr><td colspan='2'>[[6c71]] is a 4 chain structure with sequence from [http://en.wikipedia.org/wiki/Psep6 Psep6]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=6C71 OCA]. For a <b>guided tour on the structure components</b> use [http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=6C71 FirstGlance]. <br> | ||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=FAD:FLAVIN-ADENINE+DINUCLEOTIDE'>FAD</scene>, <scene name='pdbligand=NCT:(S)-3-(1-METHYLPYRROLIDIN-2-YL)PYRIDINE'>NCT</scene></td></tr> | </td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=FAD:FLAVIN-ADENINE+DINUCLEOTIDE'>FAD</scene>, <scene name='pdbligand=NCT:(S)-3-(1-METHYLPYRROLIDIN-2-YL)PYRIDINE'>NCT</scene></td></tr> | ||
<tr id='gene'><td class="sblockLbl"><b>[[Gene|Gene:]]</b></td><td class="sblockDat">PPS_4081 ([http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&srchmode=5&id=1042876 PSEP6])</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=6c71 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6c71 OCA], [http://pdbe.org/6c71 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6c71 RCSB], [http://www.ebi.ac.uk/pdbsum/6c71 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6c71 ProSAT]</span></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=6c71 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6c71 OCA], [http://pdbe.org/6c71 PDBe], [http://www.rcsb.org/pdb/explore.do?structureId=6c71 RCSB], [http://www.ebi.ac.uk/pdbsum/6c71 PDBsum], [http://prosat.h-its.org/prosat/prosatexe?pdbcode=6c71 ProSAT]</span></td></tr> | ||
</table> | </table> | ||
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__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
[[Category: Psep6]] | |||
[[Category: Allen, K N]] | [[Category: Allen, K N]] | ||
[[Category: Tararina, M A]] | [[Category: Tararina, M A]] | ||
Revision as of 12:43, 18 July 2018
Nicotine Oxidoreductase in Complex with S-nicotineNicotine Oxidoreductase in Complex with S-nicotine
Structural highlights
Publication Abstract from PubMedNicotine oxidoreductase (NicA2) is a bacterial flavoenzyme, which catalyzes the first step of nicotine catabolism by oxidizing S-nicotine into N-methyl-myosmine. It has been proposed as a biotherapeutic for nicotine addiction because of its nanomolar substrate binding affinity. The first crystal structure of NicA2 has been reported, establishing NicA2 as a member of the monoamine oxidase (MAO) family. However, substrate specificity and structural determinants of substrate binding and/or catalysis have not been explored. Herein, analysis of the pH-rate profile, single-turnover kinetics, and binding data establish that pH does not significantly affect the catalytic rate and product release is not rate-limiting. The X-ray crystal structure of NicA2 with S-nicotine refined to 2.65 A resolution reveals a hydrophobic binding site with a solvent exclusive cavity. Hydrophobic interactions predominantly orient the substrate, promoting the binding of a deprotonated species and supporting a hydride-transfer mechanism. Notably, NicA2 showed no activity against neurotransmitters oxidized by the two isoforms of human MAO. To further probe the substrate range of NicA2, enzyme activity was evaluated using a series of substrate analogues, indicating that S-nicotine is the optimal substrate and substitutions within the pyridyl ring abolish NicA2 activity. Moreover, mutagenesis and kinetic analysis of active-site residues reveal that removal of a hydrogen bond between the pyridyl ring of S-nicotine and the hydroxyl group of T381 has a 10-fold effect on KM, supporting the role of this bond in positioning the catalytically competent form of the substrate. Together, crystallography combined with kinetic analysis provides a deeper understanding of this enzyme's remarkable specificity. Crystallography Coupled with Kinetic Analysis Provides Mechanistic Underpinnings of a Nicotine-Degrading Enzyme.,Tararina MA, Xue S, Smith LC, Muellers SN, Miranda PO, Janda KD, Allen KN Biochemistry. 2018 Jul 3;57(26):3741-3751. doi: 10.1021/acs.biochem.8b00384. Epub, 2018 Jun 13. PMID:29812904[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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