Experimental Data Snapshot

  • Resolution: 2.40 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.184 

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Structure analysis of two CheY mutants: importance of the hydrogen-bond contribution to protein stability.

Wilcock, D.Pisabarro, M.T.Lopez-Hernandez, E.Serrano, L.Coll, M.

(1998) Acta Crystallogr D Biol Crystallogr 54: 378-385

  • DOI: https://doi.org/10.1107/s0907444997012158
  • Primary Citation of Related Structures:  
    1AB5, 1AB6

  • PubMed Abstract: 

    The crystal structures of two double mutants (F14N/V21T and F14N/V86T) of the signal transduction protein CheY have been determined to a resolution of 2.4 and 2.2 A, respectively. The structures were solved by molecular replacement and refined to final R values of 18.4 and 19.2%, respectively. Together with urea-denaturation experiments the structures have been used to analyse the effects of mutations where hydrophobic residues are replaced by residues capable of establishing hydrogen bonds. The large increase in stabilization (-12.1 kJ mol-1) of the mutation Phe14Asn arises from two factors: a reverse hydrophobic effect and the formation of a good N-cap at alpha-helix 1. In addition, a forward-backward hydrogen-bonding pattern, resembling an N-capping box and involving Asn14 and Arg18, has been found. The two Val to Thr mutations at the hydrophobic core have different thermodynamic effects: the mutation Val21Thr does not affect the stability of the protein while the mutation Val86Thr causes a small destabilization of 1.7 kJ mol-1. At site 21 a backward side chain-to-backbone hydrogen bond is formed inside alpha-helix 1 with the carbonyl O atom of the i - 4 residue without movement of the mutated side chain. The destabilizing effect of introducing a polar group in the core is efficiently compensated for by the formation of an extra hydrogen bond. At site 86 the new Ogamma atom escapes from the hydrophobic environment by a chi1 rotation into an adjacent hydrophilic cavity to form a new hydrogen bond. In this case the isosteric Val to Thr substitution is disruptive but the loss in stabilization energy is partly compensated by the formation of a hydrogen bond. The two crystal structures described in this work underline the significance of the hydrogen-bond component to protein stability.

  • Organizational Affiliation

    Departament de Biologia Molecular i Cel.lular, Centre d'Investigació i Desenvolupament-CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
125Escherichia coliMutation(s): 2 
Find proteins for P0AE67 (Escherichia coli (strain K12))
Explore P0AE67 
Go to UniProtKB:  P0AE67
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0AE67
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.40 Å
  • R-Value Free: 0.264 
  • R-Value Work: 0.184 
  • R-Value Observed: 0.184 
  • Space Group: P 31
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 54.31α = 90
b = 54.31β = 90
c = 91.83γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1998-02-04
    Type: Initial release
  • Version 1.1: 2008-03-24
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-11-03
    Changes: Database references
  • Version 1.4: 2023-08-02
    Changes: Refinement description