Crystal structure of T. celer L30e E90A/R92A variant

Experimental Data Snapshot

  • Resolution: 1.80 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.165 
  • R-Value Observed: 0.167 

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Stabilizing salt-bridge enhances protein thermostability by reducing the heat capacity change of unfolding.

Chan, C.H.Yu, T.H.Wong, K.B.

(2011) PLoS One 6: e21624-e21624

  • DOI: https://doi.org/10.1371/journal.pone.0021624
  • Primary Citation of Related Structures:  
    3LFO, 3RA5, 3RA6

  • PubMed Abstract: 

    Most thermophilic proteins tend to have more salt bridges, and achieve higher thermostability by up-shifting and broadening their protein stability curves. While the stabilizing effect of salt-bridge has been extensively studied, experimental data on how salt-bridge influences protein stability curves are scarce. Here, we used double mutant cycles to determine the temperature-dependency of the pair-wise interaction energy and the contribution of salt-bridges to ΔC(p) in a thermophilic ribosomal protein L30e. Our results showed that the pair-wise interaction energies for the salt-bridges E6/R92 and E62/K46 were stabilizing and insensitive to temperature changes from 298 to 348 K. On the other hand, the pair-wise interaction energies between the control long-range ion-pair of E90/R92 were negligible. The ΔC(p) of all single and double mutants were determined by Gibbs-Helmholtz and Kirchhoff analyses. We showed that the two stabilizing salt-bridges contributed to a reduction of ΔC(p) by 0.8-1.0 kJ mol⁻¹ K⁻¹. Taken together, our results suggest that the extra salt-bridges found in thermophilic proteins enhance the thermostability of proteins by reducing ΔC(p), leading to the up-shifting and broadening of the protein stability curves.

  • Organizational Affiliation

    School of Life Sciences, Centre for Protein Science and Crystallography, The Chinese University of Hong Kong, Hong Kong, Shatin, Hong Kong SAR, China.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
50S ribosomal protein L30e101Thermococcus celerMutation(s): 2 
Gene Names: rpl30erpl30
Find proteins for P29160 (Thermococcus celer)
Explore P29160 
Go to UniProtKB:  P29160
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP29160
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.80 Å
  • R-Value Free: 0.204 
  • R-Value Work: 0.165 
  • R-Value Observed: 0.167 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 23.913α = 90
b = 53.097β = 108.57
c = 33.466γ = 90
Software Package:
Software NamePurpose
CrystalCleardata collection
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-04-14
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2012-02-01
    Changes: Database references
  • Version 1.3: 2017-11-01
    Changes: Refinement description
  • Version 1.4: 2021-11-10
    Changes: Database references
  • Version 1.5: 2023-11-01
    Changes: Data collection, Refinement description