3F8P

Structure of Sulfolobus solfataricus TrxR-B3


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.205 

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Literature

Structure and stability of a thioredoxin reductase from Sulfolobus solfataricus: a thermostable protein with two functions

Ruggiero, A.Masullo, M.Ruocco, M.R.Grimaldi, P.Lanzotti, M.A.Arcari, P.Zagari, A.Vitagliano, L.

(2009) Biochim Biophys Acta 1794: 554-562

  • DOI: 10.1016/j.bbapap.2008.11.011
  • Primary Citation of Related Structures:  
    3F8D, 3F8P, 3F8R

  • PubMed Abstract: 
  • Recent investigations have demonstrated that disulfide bridges may play a crucial role in the stabilization of proteins in hyperthermophilic organisms. A major role in the process of disulfide formation is played by ubiquitous proteins belonging to the thioredoxin superfamily, which includes thioredoxins (Trx), thioredoxin reductases (TrxR), and disulfide oxidases/isomerases (PDO/PDI) ...

    Recent investigations have demonstrated that disulfide bridges may play a crucial role in the stabilization of proteins in hyperthermophilic organisms. A major role in the process of disulfide formation is played by ubiquitous proteins belonging to the thioredoxin superfamily, which includes thioredoxins (Trx), thioredoxin reductases (TrxR), and disulfide oxidases/isomerases (PDO/PDI). Here we report a characterization of the structure and stability of the TrxR (SsTrxRB3) isolated from the archaeon Sulfolobus solfataricus. This protein is particularly interesting since it is able to process different substrates (Trxs and PDO) and it is endowed with an additional NADH oxidase activity. The crystal structure of the wild-type enzyme, of its complex with NADP and of the C147A mutant provides interesting clues on the enzyme function. In contrast to what is observed for class II TrxRs, in the structure of the oxidized enzyme, the FAD binding site is occupied by a partially disordered NAD molecule. In the active site of the C147A mutant, which exhibits a marginal NADH oxidase activity, the FAD is canonically bound to the enzyme. Molecular modeling indicates that a FAD molecule can be accommodated in the site of the reduced SsTrxRB3. Depending on the oxidation state, SsTrxRB3 can bind a different cofactor in its active site. This peculiar feature has been related to its dual activity. Denaturation experiments followed by circular dichroism indicate that electrostatic interactions play an important role in the stabilization of this thermostable protein. The analysis of the enzyme 3D-structure has also provided insights into the bases of SsTrxRB3 stability.


    Organizational Affiliation

    Istituto di Biostrutture e Bioimmagini, CNR, Via Mezzocannone 16, I-80134 Napoli, Italy.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Thioredoxin reductase (TrxB-3)A, B, C, D323Saccharolobus solfataricusMutation(s): 0 
Gene Names: nox35
EC: 1.6.4.5 (PDB Primary Data), 1.6.99.3 (UniProt)
UniProt
Find proteins for Q8X236 (Saccharolobus solfataricus)
Explore Q8X236 
Go to UniProtKB:  Q8X236
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.200 
  • R-Value Observed: 0.205 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 76.766α = 90
b = 120.678β = 90
c = 126.855γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
AMoREphasing
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-01-13
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance