2Y2Z

ligand-free form of TetR-like repressor SimR


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.205 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Structures of the Tetr-Like Simocyclinone Efflux Pump Repressor, Simr, and the Mechanism of Ligand-Mediated Derepression.

Le, T.B.K.Stevenson, C.E.M.Fiedler, H.-P.Maxwell, A.Lawson, D.M.Buttner, M.J.

(2011) J.Mol.Biol. 408: 40

  • DOI: 10.1016/j.jmb.2011.02.035
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Simocyclinone D8 (SD8), a potent DNA gyrase inhibitor made by Streptomyces antibioticus, is exported from the producing organism by the SimX efflux pump. The expression of simX is under the control of SimR, a member of the TetR family of transcriptio ...

    Simocyclinone D8 (SD8), a potent DNA gyrase inhibitor made by Streptomyces antibioticus, is exported from the producing organism by the SimX efflux pump. The expression of simX is under the control of SimR, a member of the TetR family of transcriptional regulators. SimR represses simX transcription by binding to operators in the intergenic region between simR and simX. Previously, we have shown that the mature antibiotic SD8 or its biosynthetic intermediate, simocyclinone C4, can dissociate SimR from its operators, leading to derepression of simX and export of SD8 from the cell. This provides a mechanism that couples the biosynthesis of the antibiotic to its export. Here, we report the crystal structures of SimR alone and in complex with either SD8 or simocyclinone C4. The ligand-binding pocket is unusual compared to those of other characterized TetR-family transcriptional regulators: the structures show an extensive ligand-binding pocket spanning both monomers in the functional dimeric unit, with the aminocoumarin moiety of SD8 buried in the protein core, while the angucyclic polyketide moiety is partially exposed to bulk solvent. Through comparisons of the structures, we postulate a derepression mechanism for SimR that invokes rigid-body motions of the subunits relative to one another, coupled with a putative locking mechanism to restrict further conformational change.


    Organizational Affiliation

    Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
PUTATIVE REPRESSOR SIMREG2
A
267Streptomyces antibioticusMutation(s): 0 
Gene Names: simReg2 (sim16)
Find proteins for Q9AMH9 (Streptomyces antibioticus)
Go to UniProtKB:  Q9AMH9
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.234 
  • R-Value Work: 0.205 
  • Space Group: H 3 2
Unit Cell:
Length (Å)Angle (°)
a = 116.060α = 90.00
b = 116.060β = 90.00
c = 109.381γ = 120.00
Software Package:
Software NamePurpose
REFMACrefinement
SCALAdata scaling
MOSFLMdata reduction
SHELXphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-03-09
    Type: Initial release
  • Version 1.1: 2011-05-19
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2019-05-08
    Type: Data collection, Experimental preparation, Other