3NXU

Crystal structure of human cytochrome P4503A4 bound to an inhibitor ritonavir

Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.232 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history. 

Literature

Structure and mechanism of the complex between cytochrome P4503A4 and ritonavir.

Sevrioukova, I.F., Poulos, T.L.

(2010) Proc.Natl.Acad.Sci.USA 107: 18422-18427

  • DOI: 10.1073/pnas.1010693107

  • PubMed Abstract: 

    • Ritonavir is a HIV protease inhibitor routinely prescribed to HIV patients that also potently inactivates cytochrome P4503A4 (CYP3A4), the major human drug-metabolizing enzyme. By inhibiting CYP3A4, ritonavir increases plasma concentrations of other ...

    Ritonavir is a HIV protease inhibitor routinely prescribed to HIV patients that also potently inactivates cytochrome P4503A4 (CYP3A4), the major human drug-metabolizing enzyme. By inhibiting CYP3A4, ritonavir increases plasma concentrations of other anti-HIV drugs oxidized by CYP3A4 thereby improving clinical efficacy. Despite the importance and wide use of ritonavir in anti-HIV therapy, the precise mechanism of CYP3A4 inhibition remains unclear. The available data are inconsistent and suggest that ritonavir acts as a mechanism-based, competitive or mixed competitive-noncompetitive CYP3A4 inactivator. To resolve this controversy and gain functional and structural insights into the mechanism of CYP3A4 inhibition, we investigated the ritonavir binding reaction by kinetic and equilibrium analysis, elucidated how the drug affects redox properties of the hemoprotein, and determined the 2.0 Å X-ray structure of the CYP3A4-ritonavir complex. Our results show that ritonavir is a type II ligand that perfectly fits into the CYP3A4 active site cavity and irreversibly binds to the heme iron via the thiazole nitrogen, which decreases the redox potential of the protein and precludes its reduction with the redox partner, cytochrome P450 reductase.

    Organizational Affiliation: 

    Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA. sevrioui@uci.edu




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Cytochrome P450 3A4
A, B
485Homo sapiensMutation(s): 0 
Gene Names: CYP3A4 (CYP3A3)
EC: 1.14.14.-
Find proteins for P08684 (Homo sapiens)
Go to Gene View: CYP3A4
Go to UniProtKB:  P08684
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HEM
Query on HEM
Download SDF File 
Download CCD File 
A, B
PROTOPORPHYRIN IX CONTAINING FE
HEME
C34 H32 Fe N4 O4
KABFMIBPWCXCRK-RGGAHWMASA-L
 Ligand Interaction
DMS
Query on DMS
Download SDF File 
Download CCD File 
A, B
DIMETHYL SULFOXIDE
C2 H6 O S
IAZDPXIOMUYVGZ-UHFFFAOYSA-N
 Ligand Interaction
RIT
Query on RIT
Download SDF File 
Download CCD File 
A, B
RITONAVIR
A-84538
C37 H48 N6 O5 S2
NCDNCNXCDXHOMX-XGKFQTDJSA-N
 Ligand Interaction
Biologically Interesting Molecules 1 Unique
IDChainsNameType/Class2D Diagram3D Interactions
PRD_001001 (RIT)
Query on PRD_001001		A,BRITONAVIRPeptide-like / Inhibitor

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External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
RITKi: 100 - 170 nM (100) BINDINGDB
RITIC50: 30 - 550 nM (100) BINDINGDB
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.262 
  • R-Value Work: 0.232 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 162.123α = 90.00
b = 94.690β = 124.25
c = 93.130γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
CNSrefinement
MOSFLMdata reduction
Blu-Icedata collection

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2010-10-20
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2012-12-12
    Type: Other
  • Version 1.3: 2017-11-08
    Type: Refinement description