3Q7S

2.1A resolution structure of the ChxR receiver domain containing I3C from Chlamydia trachomatis


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.199 

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Ligand Structure Quality Assessment 


This is version 1.3 of the entry. See complete history


Literature

The atypical response regulator protein ChxR has structural characteristics and dimer interface interactions that are unique within the OmpR/PhoB subfamily.

Hickey, J.M.Lovell, S.Battaile, K.P.Hu, L.Middaugh, C.R.Hefty, P.S.

(2011) J Biol Chem 286: 32606-32616

  • DOI: https://doi.org/10.1074/jbc.M111.220574
  • Primary Citation of Related Structures:  
    3Q7R, 3Q7S, 3Q7T

  • PubMed Abstract: 

    Typically as a result of phosphorylation, OmpR/PhoB response regulators form homodimers through a receiver domain as an integral step in transcriptional activation. Phosphorylation stabilizes the ionic and hydrophobic interactions between monomers. Recent studies have shown that some response regulators retain functional activity in the absence of phosphorylation and are termed atypical response regulators. The two currently available receiver domain structures of atypical response regulators are very similar to their phospho-accepting homologs, and their propensity to form homodimers is generally retained. An atypical response regulator, ChxR, from Chlamydia trachomatis, was previously reported to form homodimers; however, the residues critical to this interaction have not been elucidated. We hypothesize that the intra- and intermolecular interactions involved in forming a transcriptionally competent ChxR are distinct from the canonical phosphorylation (activation) paradigm in the OmpR/PhoB response regulator subfamily. To test this hypothesis, structural and functional studies were performed on the receiver domain of ChxR. Two crystal structures of the receiver domain were solved with the recently developed method using triiodo compound I3C. These structures revealed many characteristics unique to OmpR/PhoB subfamily members: typical or atypical. Included was the absence of two α-helices present in all other OmpR/PhoB response regulators. Functional studies on various dimer interface residues demonstrated that ChxR forms relatively stable homodimers through hydrophobic interactions, and disruption of these can be accomplished with the introduction of a charged residue within the dimer interface. A gel shift study with monomeric ChxR supports that dimerization through the receiver domain is critical for interaction with DNA.


  • Organizational Affiliation

    Department of Molecular Biosciences, University of Kansas, Lawrence, Kansas 66045, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Transcriptional regulatory protein
A, B
121Chlamydia trachomatis L2/434/BuMutation(s): 0 
Gene Names: CTLon_0888
UniProt
Find proteins for A0A0H3MDW1 (Chlamydia trachomatis serovar L2 (strain ATCC VR-902B / DSM 19102 / 434/Bu))
Explore A0A0H3MDW1 
Go to UniProtKB:  A0A0H3MDW1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A0H3MDW1
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.196 
  • R-Value Observed: 0.199 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 149.766α = 90
b = 41.086β = 106.1
c = 45.069γ = 90
Software Package:
Software NamePurpose
SHELXphasing
SHELXmodel building
PHENIXrefinement
PDB_EXTRACTdata extraction
CrystalCleardata collection
HKL-2000data reduction
HKL-2000data scaling
SHELXDphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-07-20
    Type: Initial release
  • Version 1.1: 2011-11-02
    Changes: Database references
  • Version 1.2: 2018-06-06
    Changes: Data collection, Refinement description
  • Version 1.3: 2024-02-21
    Changes: Data collection, Database references, Derived calculations