3MEX

Crystal structure of MexR in oxidized state

• PDB DOI: https://doi.org/10.2210/pdb3MEX/pdb

• Classification: Transcription, Transcription Regulation
• Organism(s): Pseudomonas aeruginosa PAO1
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): Yes 


• Deposited: 2010-04-01 Released: 2010-07-28 
• Deposition Author(s): Chen, H., Yi, C., Zhang, J., Zhang, W., Yang, C.-G., He, C.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.10 Å
• R-Value Free: 
  0.260 (Depositor), 0.260 (DCC) 
• R-Value Work: 
  0.215 (Depositor), 0.210 (DCC) 
• R-Value Observed: 
  0.218 (Depositor) 

Starting Model: experimental

Literature

Structural insight into the oxidation-sensing mechanism of the antibiotic resistance of regulator MexR

Chen, H., Yi, C., Zhang, J., Zhang, W., Ge, Z., Yang, C.-G., He, C.

(2010) EMBO Rep 11: 685-690

• PubMed: 20616806 
• DOI: https://doi.org/10.1038/embor.2010.96
• Primary Citation of Related Structures:  
  3MEX


• PubMed Abstract: 
  

  MexR functions as the primary regulator of the mexAB-oprM multidrug efflux expression in Pseudomonas aeruginosa. It has been shown that MexR senses oxidative stress by interprotomer disulphide bond formation between redox-active cysteines. This oxidation induces MexR to dissociate from the promoter DNA, thus activating the transcriptional expression of efflux pump genes. In this study, we present the crystal structure of MexR in its oxidized form at a resolution of 2.1 A. This crystal structure reveals the mechanism by which oxidative signal allosterically derepresses the MexR-controlled transcription activation.

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Organizational Affiliation: 

Coordination Chemistry Institute and the State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Hankou Road, Nanjing 210093, People's Republic of China. [e-mail]

Biological Assembly 1  

Global Symmetry: Cyclic - C2  (Explore in 3D)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 32.81 kDa 
• Atom Count: 2,396 
• Modelled Residue Count: 284 
• Deposited Residue Count: 284 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Multidrug resistance operon repressor	A, B	142	Pseudomonas aeruginosa PAO1	Mutation(s): 1  Gene Names: MEXR
UniProt
Find proteins for P52003 (Pseudomonas aeruginosa (strain ATCC 15692 / DSM 22644 / CIP 104116 / JCM 14847 / LMG 12228 / 1C / PRS 101 / PAO1)) Explore P52003  Go to UniProtKB:  P52003

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.10 Å
• R-Value Free:  0.260 (Depositor), 0.260 (DCC) 
• R-Value Work:  0.215 (Depositor), 0.210 (DCC) 
• R-Value Observed: 0.218 (Depositor) 

Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 39.554	α = 90
b = 72.183	β = 90
c = 98.173	γ = 90

Software Package:

Software Name	Purpose
HKL-2000	data collection
PHASES	phasing
REFMAC	refinement
HKL-2000	data reduction
HKL-2000	data scaling

Structure Validation

Entry History 

Deposition Data

• Released Date: 2010-07-28 
Deposition Author(s): Chen, H., Yi, C., Zhang, J., Zhang, W., Yang, C.-G., He, C.

Revision History  

• Version 1.0: 2010-07-28
  Type: Initial release
  
• Version 1.1: 2011-07-13
  Changes: Version format compliance
• Version 1.2: 2023-11-01
  Changes: Data collection, Database references, Refinement description
• Version 1.3: 2024-10-30
  Changes: Structure summary