2O89

S. aureus thioredoxin P31T/C32S mutant


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.55 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.202 

wwPDB Validation   3D Report Full Report


This is version 1.5 of the entry. See complete history


Literature

The conserved active site proline determines the reducing power of Staphylococcus aureus thioredoxin

Roos, G.Garcia-Pino, A.Van Belle, K.Brosens, E.Wahni, K.Vandenbussche, G.Wyns, L.Loris, R.Messens, J.

(2007) J Mol Biol 368: 800-811

  • DOI: https://doi.org/10.1016/j.jmb.2007.02.045
  • Primary Citation of Related Structures:  
    2O7K, 2O85, 2O87, 2O89

  • PubMed Abstract: 

    Nature uses thioredoxin-like folds in several disulfide bond oxidoreductases. Each of them has a typical active site Cys-X-X-Cys sequence motif, the hallmark of thioredoxin being Trp-Cys-Gly-Pro-Cys. The intriguing role of the highly conserved proline in the ubiquitous reducing agent thioredoxin was studied by site-specific mutagenesis of Staphylococcus aureus thioredoxin (Sa_Trx). We present X-ray structures, redox potential, pK(a), steady-state kinetic parameters, and thermodynamic stabilities. By replacing the central proline to a threonine/serine, no extra hydrogen bonds with the sulphur of the nucleophilic cysteine are introduced. The only structural difference is that the immediate chemical surrounding of the nucleophilic cysteine becomes more hydrophilic. The pK(a) value of the nucleophilic cysteine decreases with approximately one pH unit and its redox potential increases with 30 mV. Thioredoxin becomes more oxidizing and the efficiency to catalyse substrate reduction (k(cat)/K(M)) decreases sevenfold relative to wild-type Sa_Trx. The oxidized form of wild-type Sa_Trx is far more stable than the reduced form over the whole temperature range. The driving force to reduce substrate proteins is the relative stability of the oxidized versus the reduced form Delta(T(1/2))(ox/red). This driving force is decreased in the Sa_Trx P31T mutant. Delta(T(1/2))(ox/red) drops from 15.5 degrees C (wild-type) to 5.8 degrees C (P31T mutant). In conclusion, the active site proline in thioredoxin determines the driving potential for substrate reduction.


  • Organizational Affiliation

    Department of Molecular and Cellular Interactions, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Thioredoxin107Staphylococcus aureusMutation(s): 2 
Gene Names: TrxA
UniProt
Find proteins for P0A0K6 (Staphylococcus aureus)
Explore P0A0K6 
Go to UniProtKB:  P0A0K6
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0A0K6
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.55 Å
  • R-Value Free: 0.255 
  • R-Value Work: 0.202 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 41.328α = 90
b = 49.228β = 90
c = 54.88γ = 90
Software Package:
Software NamePurpose
MAR345data collection
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2007-07-24
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-10-18
    Changes: Refinement description
  • Version 1.4: 2021-11-10
    Changes: Database references
  • Version 1.5: 2023-10-25
    Changes: Data collection, Refinement description