2TRX

CRYSTAL STRUCTURE OF THIOREDOXIN FROM ESCHERICHIA COLI AT 1.68 ANGSTROMS RESOLUTION


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.68 Å
  • R-Value Observed: 0.165 

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This is version 1.3 of the entry. See complete history


Literature

Crystal structure of thioredoxin from Escherichia coli at 1.68 A resolution.

Katti, S.K.LeMaster, D.M.Eklund, H.

(1990) J Mol Biol 212: 167-184

  • DOI: https://doi.org/10.1016/0022-2836(90)90313-B
  • Primary Citation of Related Structures:  
    2TRX

  • PubMed Abstract: 

    The crystal structure of thioredoxin from Escherichia coli has been refined by the stereochemically restrained least-squares procedure to a crystallographic R-factor of 0.165 at 1.68 A resolution. In the final model, the root-mean-square deviation from ideality for bond distances is 0.015 A and for angle distances 0.035 A. The structure contains 1644 protein atoms from two independent molecules, two Cu2+, 140 water molecules and seven methylpentanediol molecules. Ten residues have been modeled in two alternative conformations. E. coli thioredoxin is a compact molecule with 90% of its residues in helices, beta-strands or reverse turns. The molecule consists of two conformational domains, beta alpha beta alpha beta and beta beta alpha, connected by a single-turn alpha-helix and a 3(10) helix. The beta-sheet forms the core of the molecule packed on either side by clusters of hydrophobic residues. Helices form the external surface. The active site disulfide bridge between Cys32 and Cys35 is located at the amino terminus of the second alpha-helix. The positive electrostatic field due to the helical dipole is probably important for stabilizing the anionic intermediate during the disulfide reductase function of the protein. The more reactive cysteine, Cys32, has its sulfur atom exposed to solvent and also involved in a hydrogen bond with a backbone amide group. Residues 29 to 37, which include the active site cysteine residues, form a protrusion on the surface of the protein and make relatively fewer interactions with the rest of the structure. The disulfide bridge exhibits a right-handed conformation with a torsion angle of 81 degrees and 72 degrees about the S-S bond in the two molecules. Twenty-five pairs of water molecules obey the noncrystallographic symmetry. Most of them are involved in establishing intramolecular hydrogen-bonding interactions between protein atoms and thus serve as integral parts of the folded protein structure. Methylpentanediol molecules often pack against the loops and stabilize their structure. Cu2+ used for crystallization exhibit a distorted octahedral square bipyramid co-ordination and provide essential packing interactions in the crystal. The two independent protein molecules are very similar in conformation but distinctly different in atomic detail (root-mean-square = 0.94 A). The differences, which may be related to the crystal contacts, are localized mostly to regions far from the active site.


  • Organizational Affiliation

    Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
THIOREDOXIN
A, B
108Escherichia coliMutation(s): 0 
UniProt
Find proteins for P0AA25 (Escherichia coli (strain K12))
Explore P0AA25 
Go to UniProtKB:  P0AA25
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0AA25
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.68 Å
  • R-Value Observed: 0.165 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 89.5α = 90
b = 51.06β = 113.5
c = 60.45γ = 90
Software Package:
Software NamePurpose
PROFFTrefinement

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1991-10-15
    Type: Initial release
  • Version 1.1: 2008-03-25
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance
  • Version 1.3: 2017-11-29
    Changes: Derived calculations, Other