Crystal structure of the CHAD domain from the plant Ricinus communis

Experimental Data Snapshot

  • Resolution: 2.30 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.232 

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Molecular characterization of CHAD domains as inorganic polyphosphate-binding modules.

Lorenzo-Orts, L.Hohmann, U.Zhu, J.Hothorn, M.

(2019) Life Sci Alliance 2

  • DOI: https://doi.org/10.26508/lsa.201900385
  • Primary Citation of Related Structures:  
    6QV5, 6QV7, 6QVA

  • PubMed Abstract: 

    Inorganic polyphosphates (polyPs) are linear polymers of orthophosphate units linked by phosphoanhydride bonds. Here, we report that bacterial, archaeal, and eukaryotic conserved histidine α-helical (CHAD) domains are specific polyP-binding modules. Crystal structures reveal that CHAD domains are formed by two four-helix bundles, giving rise to a central pore surrounded by conserved basic surface patches. Different CHAD domains bind polyPs with dissociation constants ranging from the nano- to mid-micromolar range, but not nucleic acids. A CHAD-polyP complex structure reveals the phosphate polymer binding across the central pore and along the two basic patches. Mutational analysis of CHAD-polyP interface residues validates the complex structure. The presence of a CHAD domain in the polyPase ygiF enhances its enzymatic activity. The only known CHAD protein from the plant Ricinus communis localizes to the nucleus/nucleolus when expressed in Arabidopsis and tobacco, suggesting that plants may harbor polyPs in these compartments. We propose that CHAD domains may be used to engineer the properties of polyP-metabolizing enzymes and to specifically localize polyP stores in eukaryotic cells and tissues.

  • Organizational Affiliation

    Structural Plant Biology Laboratory, Department of Botany and Plant Biology, Faculty of Sciences, University of Geneva, Geneva, Switzerland michael.hothorn@unige.ch.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
CHAD domain303Ricinus communisMutation(s): 0 
Gene Names: RCOM_0386350
Find proteins for B9T8Q5 (Ricinus communis)
Explore B9T8Q5 
Go to UniProtKB:  B9T8Q5
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupB9T8Q5
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.30 Å
  • R-Value Free: 0.242 
  • R-Value Work: 0.232 
  • R-Value Observed: 0.232 
  • Space Group: P 61 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 116.427α = 90
b = 116.427β = 90
c = 119.248γ = 120
Software Package:
Software NamePurpose
XDSdata reduction
XDSdata scaling

Structure Validation

View Full Validation Report

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
European Research CouncilSwitzerland310856

Revision History  (Full details and data files)

  • Version 1.0: 2019-05-29
    Type: Initial release
  • Version 1.1: 2019-06-05
    Changes: Data collection, Database references