1M7T

Solution Structure and Dynamics of the Human-Escherichia coli Thioredoxin Chimera: Insights into Thermodynamic Stability


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 21 
  • Selection Criteria: Back calculated data agree with experimental NOESY spectrum,structures with acceptable covalent geometry,structures with favorable non-bond energy,structures with the least restraint violations,structures with the lowest energy,target function 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Solution Structure and Dynamics of the Human-Escherichia coli Thioredoxin Chimera: Insights into Thermodynamic Stability

Dangi, B.Dobrodumov, A.V.Louis, J.M.Gronenborn, A.M.

(2002) Biochemistry 41: 9376-9388


  • PubMed Abstract: 
  • We have determined the high-resolution solution structure of the oxidized form of a chimeric human and Escherichia coli thioredoxin (TRX(HE)) by NMR. The overall structure is well-defined with a rms difference for the backbone atoms of 0.27 +/- 0.06 ...

    We have determined the high-resolution solution structure of the oxidized form of a chimeric human and Escherichia coli thioredoxin (TRX(HE)) by NMR. The overall structure is well-defined with a rms difference for the backbone atoms of 0.27 +/- 0.06 A. The topology of the protein is identical to those of the human and E. coli parent proteins, consisting of a central five-stranded beta-sheet surrounded by four alpha-helices. Analysis of the interfaces between the two domains derived from the human and E. coli sequences reveals that the general hydrophobic packing is unaltered and only subtle changes in the details of side chain interactions are observed. The packing of helix alpha(4) with helix alpha(2) across the hybrid interface is less optimal than in the parent molecules, and electrostatic interactions between polar side chains are missing. In particular, lysine-glutamate salt bridges between residues on helices alpha(2) and alpha(4), which were observed in both human and E. coli proteins, are not present in the chimeric protein. The origin of the known reduced thermodynamic stability of TRX(HE) was probed by mutagenesis on the basis of these structural findings. Two mutants of TRX(HE), S44D and S44E, were created, and their thermal and chemical stabilities were examined. Improved stability toward chaotropic agents was observed for both mutants, but no increase in the denaturation temperature was seen compared to that of TRX(HE). In addition to the structural analysis, the backbone dynamics of TRX(HE) were investigated by (15)N NMR relaxation measurements. Analysis using the model free approach reveals that the protein is fairly rigid with an average S(2) of 0.88. Increased mobility is primarily present in two external loop regions comprising residues 72-74 and 92-94 that contain glycine and proline residues.


    Organizational Affiliation

    Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0560, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Chimera of Human and E. coli thioredoxin
A
107Homo sapiensSalmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720)
This entity is chimeric
Gene Names: TXN (TRDX, TRX, TRX1), trxA
Find proteins for P10599 (Homo sapiens)
Go to Gene View: TXN
Go to UniProtKB:  P10599
Find proteins for P0AA28 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720))
Go to UniProtKB:  P0AA28
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 21 
  • Selection Criteria: Back calculated data agree with experimental NOESY spectrum,structures with acceptable covalent geometry,structures with favorable non-bond energy,structures with the least restraint violations,structures with the lowest energy,target function 
  • Olderado: 1M7T Olderado

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2002-09-25
    Type: Initial release
  • Version 1.1: 2008-04-28
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance