1R4V

1.9A crystal structure of protein AQ328 from Aquifex aeolicus


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.181 
  • R-Value Observed: 0.182 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

The crystal structure of Aq_328 from the hyperthermophilic bacteria Aquifex aeolicus shows an ancestral histone fold.

Qiu, Y.Tereshko, V.Kim, Y.Zhang, R.Collart, F.Yousef, M.Kossiakoff, A.Joachimiak, A.

(2006) Proteins 62: 8-16

  • DOI: https://doi.org/10.1002/prot.20590
  • Primary Citation of Related Structures:  
    1R4V

  • PubMed Abstract: 

    The structure of Aq_328, an uncharacterized protein from hyperthermophilic bacteria Aquifex aeolicus, has been determined to 1.9 A by using multi-wavelength anomalous diffraction (MAD) phasing. Although the amino acid sequence analysis shows that Aq_328 has no significant similarity to proteins with a known structure and function, the structure comparison by using the Dali server reveals that it: (1) assumes a histone-like fold, and (2) is similar to an ancestral nuclear histone protein (PDB code 1F1E) with z-score 8.1 and RMSD 3.6 A over 124 residues. A sedimentation equilibrium experiment indicates that Aq_328 is a monomer in solution, with an average sedimentation coefficient of 2.4 and an apparent molecular weight of about 20 kDa. The overall architecture of Aq_328 consists of two noncanonical histone domains in tandem repeat within a single chain, and is similar to eukaryotic heterodimer (H2A/H2B and H3/H4) and an archaeal histone heterodimer (HMfA/HMfB). The sequence comparisons between the two histone domains of Aq_328 and six eukaryotic/archaeal histones demonstrate that most of the conserved residues that underlie the Aq_328 architecture are used to build and stabilize the two cross-shaped antiparallel histone domains. The high percentage of salt bridges in the structure could be a factor in the protein's thermostability. The structural similarities to other histone-like proteins, molecular properties, and potential function of Aq_328 are discussed in this paper.


  • Organizational Affiliation

    Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, Illinois 60637, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Hypothetical protein AQ_328171Aquifex aeolicus VF5Mutation(s): 7 
Gene Names: AQ_328
UniProt
Find proteins for O66665 (Aquifex aeolicus (strain VF5))
Explore O66665 
Go to UniProtKB:  O66665
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO66665
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.90 Å
  • R-Value Free: 0.213 
  • R-Value Work: 0.181 
  • R-Value Observed: 0.182 
  • Space Group: P 65 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 56.036α = 90
b = 56.036β = 90
c = 244.768γ = 120
Software Package:
Software NamePurpose
REFMACrefinement
HKL-2000data reduction
SCALEPACKdata scaling
SOLVEphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2004-03-30
    Type: Initial release
  • Version 1.1: 2008-04-29
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Source and taxonomy, Version format compliance