5M7O

Crystal structure of NtrX from Brucella abortus processed with the CrystalDirect automated mounting and cryo-cooling technology


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.269 
  • R-Value Work: 0.227 
  • R-Value Observed: 0.230 

wwPDB Validation   3D Report Full Report


This is version 1.1 of the entry. See complete history


Literature

Three-Dimensional Structure of Full-Length NtrX, an Unusual Member of the NtrC Family of Response Regulators.

Fernandez, I.Cornaciu, I.Carrica, M.D.Uchikawa, E.Hoffmann, G.Sieira, R.Marquez, J.A.Goldbaum, F.A.

(2017) J Mol Biol 429: 1192-1212

  • DOI: https://doi.org/10.1016/j.jmb.2016.12.022
  • Primary Citation of Related Structures:  
    5M7N, 5M7O, 5M7P

  • PubMed Abstract: 

    Bacteria sense and adapt to environmental changes using two-component systems. These signaling pathways are formed by a histidine kinase that phosphorylates a response regulator (RR), which finally modulates the transcription of target genes. The bacterium Brucella abortus codes for a two-component system formed by the histidine kinase NtrY and the RR NtrX that participates in sensing low oxygen tension and generating an adaptive response. NtrX is a modular protein with REC, AAA+, and DNA-binding domains, an architecture that classifies it among the NtrC subfamily of RRs. However, it lacks the signature GAFTGA motif that is essential for activating transcription by the mechanism proposed for canonical members of this subfamily. In this article, we present the first crystal structure of full-length NtrX, which is also the first structure of a full-length NtrC-like RR with all the domains solved, showing that the protein is structurally similar to other members of the subfamily. We also report that NtrX binds nucleotides and the structures of the protein bound to ATP and ADP. Despite binding ATP, NtrX does not have ATPase activity and does not form oligomers in response to phosphorylation or nucleotide binding. We also identify a nucleotide sequence recognized by NtrX that allows it to bind to a promoter region that regulates its own transcription and to establish a negative feedback mechanism to modulate its expression. Overall, this article provides a detailed description of the NtrX RR and supports that it functions by a mechanism different to classical NtrC-like RRs.


  • Organizational Affiliation

    Fundación Instituto Leloir, IIBBA-CONICET, Patricias Argentinas 435, C1405BWE Buenos Aires, Argentina.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Nitrogen assimilation regulatory protein
A, B
454Brucella abortus str. 2308 AMutation(s): 0 
Gene Names: BAAA_2000042
UniProt
Find proteins for C4IRH0 (Brucella abortus str. 2308 A)
Explore C4IRH0 
Go to UniProtKB:  C4IRH0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupC4IRH0
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.20 Å
  • R-Value Free: 0.269 
  • R-Value Work: 0.227 
  • R-Value Observed: 0.230 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 124.778α = 90
b = 191.228β = 90
c = 111.85γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata reduction
SCALAdata scaling
SHELXCDphasing

Structure Validation

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Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Agencia Nacional de Promocion Cientifica y TecnologicaArgentinaPICT-2013-1629
BioStruct-XFrance283570
iNEXTFrance653706

Revision History  (Full details and data files)

  • Version 1.0: 2017-01-25
    Type: Initial release
  • Version 1.1: 2017-04-26
    Changes: Database references