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==The Role of Asn 242 in P450cin== | |||
<StructureSection load='3be0' size='340' side='right'caption='[[3be0]], [[Resolution|resolution]] 3.05Å' scene=''> | |||
== Structural highlights == | |||
<table><tr><td colspan='2'>[[3be0]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Citrobacter_braakii Citrobacter braakii]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3BE0 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3BE0 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]] 3.05Å</td></tr> | |||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CNL:1,3,3-TRIMETHYL-2-OXABICYCLO[2.2.2]OCTANE'>CNL</scene>, <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</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=3be0 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3be0 OCA], [https://pdbe.org/3be0 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3be0 RCSB], [https://www.ebi.ac.uk/pdbsum/3be0 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3be0 ProSAT]</span></td></tr> | |||
</table> | |||
== Function == | |||
[https://www.uniprot.org/uniprot/CINA_CITBR CINA_CITBR] Involved in the degradation of cineol (eucalyptol). Catalyzes the initial hydroxylation of cineole exclusively at the pro-R carbon to give the (S)-6beta-hydroxycineole. Cineole is the natural substrate of CinA. | |||
== 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/be/3be0_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=3be0 ConSurf]. | |||
<div style="clear:both"></div> | |||
<div style="background-color:#fffaf0;"> | |||
== Publication Abstract from PubMed == | |||
Cytochrome P450cin (CYP176A1) is a bacterial P450 isolated from Citrobacter braakii that catalyzes the hydroxylation of cineole to (S)-6beta-hydroxycineole. This initiates the biodegradation of cineole, enabling C. braakii to live on cineole as its sole source of carbon and energy. P450cin lacks the almost universally conserved threonine residue believed to be involved in dioxygen activation and instead contains an asparagine at this position (Asn-242). To investigate the role of Asn-242 in P450cin catalysis, it was converted to alanine, and the resultant mutant was characterized. The characteristic CO-bound spectrum and spectrally determined K(D) for substrate binding were unchanged in the mutant. The x-ray crystal structures of the substrate-free and -bound N242A mutant were determined and show that the only significant change is in a reorientation of the substrate such that (R)-6alpha-hydroxycineole should be a major product. Molecular dynamics simulations of both wild type and mutant are consistent with the change in regio- and stereoselectivity predicted from the crystal structure. The mutation has only a modest effect on enzyme activity and on the diversion of the NADPH-reducing equivalent toward unproductive peroxide formation. Product profile analysis shows that (R)-6alpha-hydroxycineole is the main product, which is consistent with the crystal structure. These results demonstrate that Asn-242 is not a functional replacement for the conserved threonine in other P450s but, rather, is critical in controlling regioselective substrate oxidation. | |||
The critical role of substrate-protein hydrogen bonding in the control of regioselective hydroxylation in p450cin.,Meharenna YT, Slessor KE, Cavaignac SM, Poulos TL, De Voss JJ J Biol Chem. 2008 Apr 18;283(16):10804-12. Epub 2008 Feb 12. PMID:18270198<ref>PMID:18270198</ref> | |||
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.<br> | |||
</div> | |||
<div class="pdbe-citations 3be0" style="background-color:#fffaf0;"></div> | |||
== | ==See Also== | ||
*[[Cytochrome P450 3D structures|Cytochrome P450 3D structures]] | |||
== References == | |||
<references/> | |||
__TOC__ | |||
</StructureSection> | |||
[[Category: Citrobacter braakii]] | [[Category: Citrobacter braakii]] | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: Meharenna | [[Category: Meharenna YT]] | ||
[[Category: Poulos | [[Category: Poulos TL]] | ||
Latest revision as of 17:44, 1 November 2023
The Role of Asn 242 in P450cinThe Role of Asn 242 in P450cin
Structural highlights
FunctionCINA_CITBR Involved in the degradation of cineol (eucalyptol). Catalyzes the initial hydroxylation of cineole exclusively at the pro-R carbon to give the (S)-6beta-hydroxycineole. Cineole is the natural substrate of CinA. 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 PubMedCytochrome P450cin (CYP176A1) is a bacterial P450 isolated from Citrobacter braakii that catalyzes the hydroxylation of cineole to (S)-6beta-hydroxycineole. This initiates the biodegradation of cineole, enabling C. braakii to live on cineole as its sole source of carbon and energy. P450cin lacks the almost universally conserved threonine residue believed to be involved in dioxygen activation and instead contains an asparagine at this position (Asn-242). To investigate the role of Asn-242 in P450cin catalysis, it was converted to alanine, and the resultant mutant was characterized. The characteristic CO-bound spectrum and spectrally determined K(D) for substrate binding were unchanged in the mutant. The x-ray crystal structures of the substrate-free and -bound N242A mutant were determined and show that the only significant change is in a reorientation of the substrate such that (R)-6alpha-hydroxycineole should be a major product. Molecular dynamics simulations of both wild type and mutant are consistent with the change in regio- and stereoselectivity predicted from the crystal structure. The mutation has only a modest effect on enzyme activity and on the diversion of the NADPH-reducing equivalent toward unproductive peroxide formation. Product profile analysis shows that (R)-6alpha-hydroxycineole is the main product, which is consistent with the crystal structure. These results demonstrate that Asn-242 is not a functional replacement for the conserved threonine in other P450s but, rather, is critical in controlling regioselective substrate oxidation. The critical role of substrate-protein hydrogen bonding in the control of regioselective hydroxylation in p450cin.,Meharenna YT, Slessor KE, Cavaignac SM, Poulos TL, De Voss JJ J Biol Chem. 2008 Apr 18;283(16):10804-12. Epub 2008 Feb 12. PMID:18270198[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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