1GEQ

Entropic stabilization of the tryptophan synthase A-subunit from a hyperthermophile, pyrococcus furiosus: X-ray analysis and calorimetry


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.198 

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This is version 1.3 of the entry. See complete history

Literature

Entropic stabilization of the tryptophan synthase alpha-subunit from a hyperthermophile, Pyrococcus furiosus. X-ray analysis and calorimetry.

Yamagata, Y.Ogasahara, K.Hioki, Y.Lee, S.J.Nakagawa, A.Nakamura, H.Ishida, M.Kuramitsu, S.Yutani, K.

(2001) J.Biol.Chem. 276: 11062-11071

  • DOI: 10.1074/jbc.M009987200
  • Also Cited By: 2E09, 2DZX, 2DZW, 2DZV, 2DZU, 2DZT, 2DZS, 2DZP

  • PubMed Abstract: 
  • The structure of the tryptophan synthase alpha-subunit from Pyrococcus furiosus was determined by x-ray analysis at 2.0-A resolution, and its stability was examined by differential scanning calorimetry. Although the structure of the tryptophan syntha ...

    The structure of the tryptophan synthase alpha-subunit from Pyrococcus furiosus was determined by x-ray analysis at 2.0-A resolution, and its stability was examined by differential scanning calorimetry. Although the structure of the tryptophan synthase alpha(2)beta(2) complex from Salmonella typhimurium has been already determined, this is the first report of the structure of the alpha-subunit alone. The alpha-subunit from P. furiosus (Pf-alpha-subunit) lacked 12 and 6 residues at the N and C termini, respectively, and one residue each in two loop regions as compared with that from S. typhimurium (St-alpha-subunit), resulting in the absence of an N-terminal helix and the shortening of a C-terminal helix. The structure of the Pf-alpha-subunit was essentially similar to that of the St-alpha-subunit in the alpha(2)beta(2) complex. The differences between both structures were discussed in connection with the higher stability of the Pf-alpha-subunit and the complex formation of the alpha- and beta-subunits. Calorimetric results indicated that the Pf-alpha-subunit has extremely high thermostability and that its higher stability is caused by an entropic effect. On the basis of structural information of both proteins, we analyzed the contributions of each stabilization factor and could conclude that hydrophobic interactions in the protein interior do not contribute to the higher stability of the Pf-alpha-subunit. Rather, the increase in ion pairs, decrease in cavity volume, and entropic effects due to shortening of the polypeptide chain play important roles in extremely high stability in Pf-alpha-subunit.


    Organizational Affiliation

    Graduate School of Pharmaceutical Sciences, and Institute for Protein Research, Osaka University, Yamadaoka, Suita, Osaka 565-0871, Japan.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
TRYPTOPHAN SYNTHASE ALPHA-SUBUNIT
A, B
248Pyrococcus furiosus (strain ATCC 43587 / DSM 3638 / JCM 8422 / Vc1)Gene Names: trpA
EC: 4.2.1.20
Find proteins for Q8U094 (Pyrococcus furiosus (strain ATCC 43587 / DSM 3638 / JCM 8422 / Vc1))
Go to UniProtKB:  Q8U094
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.198 
  • Space Group: C 2 2 21
Unit Cell:
Length (Å)Angle (°)
a = 73.013α = 90.00
b = 78.997β = 90.00
c = 170.964γ = 90.00
Software Package:
Software NamePurpose
SHARPphasing
CNSrefinement
SCALEPACKdata scaling
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2000-12-13
    Type: Initial release
  • Version 1.1: 2008-04-24
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2011-11-16
    Type: Atomic model