4UA1

Crystal structure of dual function transcriptional regulator MerR form Bacillus megaterium MB1 in complex with mercury (II) ion


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.56 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.226 
  • R-Value Observed: 0.232 

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This is version 1.1 of the entry. See complete history


Literature

Structural basis of the mercury(II)-mediated conformational switching of the dual-function transcriptional regulator MerR

Chang, C.C.Lin, L.Y.Zou, X.W.Huang, C.C.Chan, N.L.

(2015) Nucleic Acids Res 43: 7612-7623

  • DOI: 10.1093/nar/gkv681
  • Primary Citation of Related Structures:  
    4UA1, 4UA2

  • PubMed Abstract: 
  • The mer operon confers bacterial resistance to inorganic mercury (Hg(2+)) and organomercurials by encoding proteins involved in sensing, transport and detoxification of these cytotoxic agents. Expression of the mer operon is under tight control by the dual-function transcriptional regulator MerR ...

    The mer operon confers bacterial resistance to inorganic mercury (Hg(2+)) and organomercurials by encoding proteins involved in sensing, transport and detoxification of these cytotoxic agents. Expression of the mer operon is under tight control by the dual-function transcriptional regulator MerR. The metal-free, apo MerR binds to the mer operator/promoter region as a repressor to block transcription initiation, but is converted into an activator upon Hg(2+)-binding. To understand how MerR interacts with Hg(2+) and how Hg(2+)-binding modulates MerR function, we report here the crystal structures of apo and Hg(2+)-bound MerR from Bacillus megaterium, corresponding respectively to the repressor and activator conformation of MerR. To our knowledge, the apo-MerR structure represents the first visualization of a MerR family member in its intact and inducer-free form. And the Hg(2+)-MerR structure offers the first view of a triligated Hg(2+)-thiolate center in a metalloprotein, confirming that MerR binds Hg(2+) via trigonal planar coordination geometry. Structural comparison revealed the conformational transition of MerR is coupled to the assembly/disassembly of a buried Hg(2+) binding site, thereby providing a structural basis for the Hg(2+)-mediated functional switching of MerR. The pronounced Hg(2+)-induced repositioning of the MerR DNA-binding domains suggests a plausible mechanism for the transcriptional regulation of the mer operon.


    Organizational Affiliation

    Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei 100, Taiwan Institute of Biochemistry, College of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan Agricultural Biotechnology Centre, National Chung Hsing University, Taichung 402, Taiwan nlchan@ntu.edu.tw.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Regulatory proteinA, B132Priestia megateriumMutation(s): 0 
Gene Names: merRmerR1
UniProt
Find proteins for Q799U3 (Bacillus megaterium)
Explore Q799U3 
Go to UniProtKB:  Q799U3
Protein Feature View
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
HG
Query on HG

Download Ideal Coordinates CCD File 
C [auth A], D [auth A]MERCURY (II) ION
Hg
BQPIGGFYSBELGY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.56 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.226 
  • R-Value Observed: 0.232 
  • Space Group: P 2 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 70.005α = 90
b = 70.556β = 90
c = 71.614γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
Blu-Icedata collection
HKL-2000data scaling
HKL-2000data processing
PHENIXmodel building

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2015-07-22
    Type: Initial release
  • Version 1.1: 2015-09-16
    Changes: Database references