3r1b: Difference between revisions
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==Open crystal structure of cytochrome P450 2B4 covalently bound to the mechanism-based inactivator tert-butylphenylacetylene== | ==Open crystal structure of cytochrome P450 2B4 covalently bound to the mechanism-based inactivator tert-butylphenylacetylene== | ||
<StructureSection load='3r1b' size='340' side='right' caption='[[3r1b]], [[Resolution|resolution]] 3.00Å' scene=''> | <StructureSection load='3r1b' size='340' side='right'caption='[[3r1b]], [[Resolution|resolution]] 3.00Å' scene=''> | ||
== Structural highlights == | == Structural highlights == | ||
<table><tr><td colspan='2'>[[3r1b]] is a 4 chain structure with sequence from [ | <table><tr><td colspan='2'>[[3r1b]] is a 4 chain structure with sequence from [https://en.wikipedia.org/wiki/Oryctolagus_cuniculus Oryctolagus cuniculus]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=3R1B OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=3R1B FirstGlance]. <br> | ||
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat"><scene name='pdbligand=CM5:5-CYCLOHEXYL-1-PENTYL-BETA-D-MALTOSIDE'>CM5</scene>, <scene name='pdbligand= | </td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 3Å</td></tr> | ||
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=CM5:5-CYCLOHEXYL-1-PENTYL-BETA-D-MALTOSIDE'>CM5</scene>, <scene name='pdbligand=FRU:FRUCTOSE'>FRU</scene>, <scene name='pdbligand=GLC:ALPHA-D-GLUCOSE'>GLC</scene>, <scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=PRD_900003:sucrose'>PRD_900003</scene>, <scene name='pdbligand=TB2:(4-TERT-BUTYLPHENYL)ACETALDEHYDE'>TB2</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=3r1b FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=3r1b OCA], [https://pdbe.org/3r1b PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=3r1b RCSB], [https://www.ebi.ac.uk/pdbsum/3r1b PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=3r1b ProSAT]</span></td></tr> | |||
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[ | |||
</table> | </table> | ||
== Function == | == Function == | ||
[ | [https://www.uniprot.org/uniprot/CP2B4_RABIT CP2B4_RABIT] Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally unrelated compounds, including steroids, fatty acids, and xenobiotics. In the epoxidation of arachidonic acid it has a unique preference for the 5,6-olefin. | ||
<div style="background-color:#fffaf0;"> | <div style="background-color:#fffaf0;"> | ||
== Publication Abstract from PubMed == | == Publication Abstract from PubMed == | ||
| Line 23: | Line 21: | ||
==See Also== | ==See Also== | ||
*[[Cytochrome P450|Cytochrome P450]] | *[[Cytochrome P450 3D structures|Cytochrome P450 3D structures]] | ||
== References == | == References == | ||
<references/> | <references/> | ||
__TOC__ | __TOC__ | ||
</StructureSection> | </StructureSection> | ||
[[Category: | [[Category: Large Structures]] | ||
[[Category: | [[Category: Oryctolagus cuniculus]] | ||
[[Category: Gay | [[Category: Gay SC]] | ||
[[Category: Halpert | [[Category: Halpert JR]] | ||
[[Category: Hollenberg | [[Category: Hollenberg PF]] | ||
[[Category: Stout | [[Category: Stout CD]] | ||
[[Category: Zhang | [[Category: Zhang H]] | ||
Latest revision as of 13:22, 6 November 2024
Open crystal structure of cytochrome P450 2B4 covalently bound to the mechanism-based inactivator tert-butylphenylacetyleneOpen crystal structure of cytochrome P450 2B4 covalently bound to the mechanism-based inactivator tert-butylphenylacetylene
Structural highlights
FunctionCP2B4_RABIT Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It oxidizes a variety of structurally unrelated compounds, including steroids, fatty acids, and xenobiotics. In the epoxidation of arachidonic acid it has a unique preference for the 5,6-olefin. Publication Abstract from PubMedA combined structural and computational analysis of rabbit cytochrome P450 2B4 covalently bound to the mechanism-based inactivator tert-butylphenylacetylene (tBPA) has yielded insight into how the enzyme retains partial activity. Since conjugation to tBPA modifies a highly conserved active site residue, the residual activity of tBPA-labeled 2B4 observed in previous studies was puzzling. Here we describe the first crystal structures of a modified mammalian P450, which show an oxygenated metabolite of tBPA conjugated to Thr 302 of helix I. These results are consistent with previous studies that identified Thr 302 as the site of conjugation. In each structure, the core of 2B4 remains unchanged, but the arrangement of plastic regions differs. This results in one structure that is compact and closed. In this conformation, tBPA points toward helix B', making a 31 degrees angle with the heme plane. This conformation is in agreement with previously performed in silico experiments. However, dimerization of 2B4 in the other structure, which is caused by movement of the B/C loop and helices F through G, alters the position of tBPA. In this case, tBPA lies almost parallel to the heme plane due to the presence of helix F' of the opposite monomer entering the active site to stabilize the dimer. However, docking experiments using this open form show that tBPA is able to rotate upward to give testosterone and 7-ethoxy-4-trifluoromethylcoumarin access to the heme, which could explain the previously observed partial activity. Structural Analysis of Mammalian Cytochrome P450 2B4 Covalently Bound to the Mechanism-Based Inactivator tert-Butylphenylacetylene: Insight into Partial Enzymatic Activity.,Gay SC, Zhang H, Wilderman PR, Roberts AG, Liu T, Li S, Lin HL, Zhang Q, Woods VL, Stout CD, Hollenberg PF, Halpert JR Biochemistry. 2011 Apr 21. PMID:21510666[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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