8EWQ image
Entry Detail
PDB ID:
8EWQ
Title:
Crystal structure of CYP3A4 bound to an inhibitor
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2022-10-24
Release Date:
2023-02-01
Method Details:
Experimental Method:
Resolution:
2.25 Å
R-Value Free:
0.26
R-Value Work:
0.23
R-Value Observed:
0.23
Space Group:
I 2 2 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Cytochrome P450 3A4
Mutations:residues 3-22 deleted, C-terminal 4-histidine tag
Chain IDs:A
Chain Length:487
Number of Molecules:1
Biological Source:Homo sapiens
Primary Citation
Dynamic Ir(III) Photosensors for the Major Human Drug-Metabolizing Enzyme Cytochrome P450 3A4.
Inorg.Chem. 62 3305 3320 (2023)
PMID: 36758158 DOI: 10.1021/acs.inorgchem.3c00059

Abstact

Probing the activity of cytochrome P450 3A4 (CYP3A4) is critical for monitoring the metabolism of pharmaceuticals and identifying drug-drug interactions. A library of Ir(III) probes that detect occupancy of the CYP3A4 active site were synthesized and characterized. These probes show selectivity for CYP3A4 inhibition, low cellular toxicity, Kd values as low as 9 nM, and are highly emissive with lifetimes up to 3.8 μs in cell growth media under aerobic conditions. These long emission lifetimes allow for time-resolved gating to distinguish probe from background autofluorescence from growth media and live cells. X-ray crystallographic analysis revealed structure-activity relationships and the preference or indifference of CYP3A4 toward resolved stereoisomers. Ir(III)-based probes show emission quenching upon CYP3A4 binding, then emission increases following displacement with CYP3A4 inhibitors or substrates. Importantly, the lead probes inhibit the activity of CYP3A4 at concentrations as low as 300 nM in CYP3A4-overexpressing HepG2 cells that accurately mimic human hepatic drug metabolism. Thus, the Ir(III)-based agents show promise as novel chemical tools for monitoring CYP3A4 active site occupancy in a high-throughput manner to gain insight into drug metabolism and drug-drug interactions.

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