1AUC

HUMAN THIOREDOXIN (OXIDIZED WITH DIAMIDE)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.270 
  • R-Value Work: 0.190 
  • R-Value Observed: 0.190 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Human thioredoxin homodimers: regulation by pH, role of aspartate 60, and crystal structure of the aspartate 60 --> asparagine mutant.

Andersen, J.F.Sanders, D.A.Gasdaska, J.R.Weichsel, A.Powis, G.Montfort, W.R.

(1997) Biochemistry 36: 13979-13988

  • DOI: 10.1021/bi971004s
  • Primary Citation of Related Structures:  
    1AIU, 1AUC

  • PubMed Abstract: 
  • Thioredoxins are a group of ca. 12 kDa redox proteins that mediate numerous cytosolic processes in all cells. Human thioredoxin can be exported out of the cell where it has additional functions including the ability to stimulate cell growth. A recent ...

    Thioredoxins are a group of ca. 12 kDa redox proteins that mediate numerous cytosolic processes in all cells. Human thioredoxin can be exported out of the cell where it has additional functions including the ability to stimulate cell growth. A recent crystal structure determination of human thioredoxin revealed an inactive dimeric form of the protein covalently linked through a disulfide bond involving Cys 73 from each monomer [Weichsel et al. (1996) Structure 4, 735-751]. In the present study, apparent dissociation constants (Kapp) for the noncovalently linked dimers were determined at various pHs using a novel assay in which preformed dimers, but not monomers, were rapidly linked through oxidation (with diamide) of the Cys 73 disulfide bond, and the relative amounts of monomer and dimer were detected by gel filtration. The values obtained were pH-dependent, varying between 6.1 and 166 microM for the pH range of 3.8-8.0, and were consistent with the titration of a single ionizable group having a pKa of 6.5. A similar value was obtained using gel filtration at pH 3.8 (Kapp = 164 microM), and the crystal structure of the diamide-oxidized protein was determined to be nearly identical to that obtained in the absence of diamide. Asp 60 lies in the dimer interface and was found to be responsible for the pH dependence for dimer formation, and therefore must have a pKa elevated by approximately 2.5 pH units. Mutation of Asp 60 to asparagine abolished nearly all of the pH dependence for dimer formation. The crystal structure of the D60N mutant revealed a dimer nearly identical to the wild type, but, surprisingly, it had the Asn 60 side chain rotated out of the dimer interface and replaced with two water molecules. The values obtained for Kapp suggest human thioredoxin may dimerize in vivo and possible roles for such dimers are discussed.


    Related Citations: 
    • Crystal Structures of Reduced, Oxidized, and Mutated Human Thioredoxins: Evidence for a Regulatory Homodimer
      Weichsel, A., Gasdaska, J.R., Powis, G., Montfort, W.R.
      (1996) Structure 4: 735

    Organizational Affiliation

    Department of Biochemistry and Arizona Cancer Center, University of Arizona, Tucson, Arizona 85721, USA.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
THIOREDOXINA105Homo sapiensMutation(s): 0 
Gene Names: TXNTRDXTRXTRX1
Find proteins for P10599 (Homo sapiens)
Explore P10599 
Go to UniProtKB:  P10599
NIH Common Fund Data Resources
PHAROS  P10599
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 0.270 
  • R-Value Work: 0.190 
  • R-Value Observed: 0.190 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 67.75α = 90
b = 26.29β = 95.14
c = 51.62γ = 90
Software Package:
Software NamePurpose
X-PLORmodel building
X-PLORrefinement
MADNESdata reduction
PROCORdata reduction
FBSCALEdata reduction
X-PLORphasing

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 1998-02-25
    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: 2018-04-18
    Changes: Data collection, Other