View source for 6unj


==Human CYP3A4 bound to an inhibitor==
<StructureSection load='6unj' size='340' side='right'caption='[[6unj]], [[Resolution|resolution]] 2.60&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[6unj]] 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=6UNJ OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=6UNJ 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]] 2.6&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=HEM:PROTOPORPHYRIN+IX+CONTAINING+FE'>HEM</scene>, <scene name='pdbligand=QDY:~{tert}-butyl+~{N}-[(2~{R})-1-naphthalen-1-yl-3-[(2~{S})-1-oxidanylidene-3-phenyl-1-(2-pyridin-3-ylethylamino)propan-2-yl]sulfanyl-propan-2-yl]carbamate'>QDY</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=6unj FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=6unj OCA], [https://pdbe.org/6unj PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=6unj RCSB], [https://www.ebi.ac.uk/pdbsum/6unj PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=6unj ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CP3A4_HUMAN CP3A4_HUMAN] Cytochromes P450 are a group of heme-thiolate monooxygenases. In liver microsomes, this enzyme is involved in an NADPH-dependent electron transport pathway. It performs a variety of oxidation reactions (e.g. caffeine 8-oxidation, omeprazole sulphoxidation, midazolam 1'-hydroxylation and midazolam 4-hydroxylation) of structurally unrelated compounds, including steroids, fatty acids, and xenobiotics. Acts as a 1,8-cineole 2-exo-monooxygenase. The enzyme also hydroxylates etoposide.<ref>PMID:11159812</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
Identification of structural determinants required for potent inhibition of drug-metabolizing cytochrome P450 3A4 (CYP3A4) could help develop safer drugs and more effective pharmacoenhancers. We utilize a rational inhibitor design to decipher structure-activity relationships in analogues of ritonavir, a highly potent CYP3A4 inhibitor marketed as pharmacoenhancer. Analysis of compounds with the R1 side-group as phenyl or naphthalene and R2 as indole or naphthalene in different stereo configuration showed that (i) analogues with the R2-naphthalene tend to bind tighter and inhibit CYP3A4 more potently than the R2-phenyl/indole containing counterparts; (ii) stereochemistry becomes a more important contributing factor, as the bulky side-groups limit the ability to optimize protein-ligand interactions; (iii) the relationship between the R1/R2 configuration and preferential binding to CYP3A4 is complex and depends on the side-group functionality/interplay and backbone spacing; and (iv) three inhibitors, 5a-b and 7d, were superior to ritonavir (IC50 of 0.055-0.085 muM vs. 0.130 muM, respectively).

An increase in side-group hydrophobicity largely improves the potency of ritonavir-like inhibitors of CYP3A4.,Samuels ER, Sevrioukova IF Bioorg Med Chem. 2020 Mar 15;28(6):115349. doi: 10.1016/j.bmc.2020.115349. Epub, 2020 Jan 31. PMID:32044230<ref>PMID:32044230</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 6unj" style="background-color:#fffaf0;"></div>

==See Also==
*[[Cytochrome P450 3D structures|Cytochrome P450 3D structures]]
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Sevrioukova I]]