3Q7T

2.15A resolution structure (I41 Form) of the ChxR receiver domain from Chlamydia trachomatis


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.205 

wwPDB Validation 3D Report Full Report


This is version 1.1 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: 10.1074/jbc.M111.220574
  • Primary Citation of Related Structures:  

  • 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. R ...

    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: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Transcriptional regulatory protein
A, B
121Chlamydia trachomatis serovar L2 (strain 434/Bu / ATCC VR-902B)Mutation(s): 0 
Gene Names: chxR
Find proteins for A0A0H3MDW1 (Chlamydia trachomatis serovar L2 (strain 434/Bu / ATCC VR-902B))
Go to UniProtKB:  A0A0H3MDW1
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NA
Query on NA

Download SDF File 
Download CCD File 
A
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.15 Å
  • R-Value Free: 0.247 
  • R-Value Work: 0.205 
  • Space Group: I 41
Unit Cell:
Length (Å)Angle (°)
a = 53.720α = 90.00
b = 53.720β = 90.00
c = 190.090γ = 90.00
Software Package:
Software NamePurpose
d*TREKdata scaling
PDB_EXTRACTdata extraction
PHENIXrefinement
PHASERphasing
d*TREKdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2011-07-20
    Type: Initial release
  • Version 1.1: 2011-11-02
    Type: Database references