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A thermodynamic analysis of conformational change due to the alpha 2 beta 2 complex formation of tryptophan synthase.

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  • المؤلفون: Hiraga K;Hiraga K; Yutani K
  • المصدر:
    European journal of biochemistry [Eur J Biochem] 1996 Aug 15; Vol. 240 (1), pp. 63-70.
  • نوع النشر :
    Journal Article; Research Support, Non-U.S. Gov't
  • اللغة:
    English
  • معلومة اضافية
    • المصدر:
      Publisher: Blackwell Science Ltd. on behalf of the Federation of European Biochemical Societies Country of Publication: England NLM ID: 0107600 Publication Model: Print Cited Medium: Print ISSN: 0014-2956 (Print) Linking ISSN: 00142956 NLM ISO Abbreviation: Eur J Biochem Subsets: MEDLINE
    • بيانات النشر:
      Publication: -2004: Oxford, UK : Blackwell Science Ltd. on behalf of the Federation of European Biochemical Societies
      Original Publication: Berlin, New York, Springer.
    • الموضوع:
    • نبذة مختصرة :
      A characteristic property of the tryptophan synthase alpha 2 beta 2 complex is the mutual activation of the alpha and beta subunit upon complex formation. It has been speculated that this mutual activation results from the conformational change due to the alpha/beta subunit interaction. To elucidate this mechanism, we investigated the thermodynamic parameters of association for the various combinations of the alpha and beta subunits from Escherichia coli and Salmonella typhimurium using isothermal titration calorimetry. The negative association enthalpy of the S. typhimurium alpha subunit with the beta subunit from E. coli (or S. typhimurium) was about 20 kJ mol-1 larger than that of the E. coli alpha subunit at 40 degrees C. However, the favorable enthalpy of the S. typhimurium alpha subunit was perfectly compensated by the unfavorable association entropy, therefore, the Gibbs energy of association was similar to that of the E. coli alpha subunit. Furthermore, the site-directed mutagenesis study revealed that a single mutation (K109N; [Asn109] alpha subunit) of the E coli alpha subunit at the subunit interface from E. coli to the S. typhimurium type could change the characteristics of the thermodynamic parameters of association to the S. typhimurium alpha subunit type. The heat-capacity changes of the association of the alpha subunit with the beta subunit were quite great, 6.37-8.21 kJ mol-1 K-1, compared with that due to a decrease in accessible surface area in the subunit interface. The analysis of the thermodynamic parameters of association suggested that the complex formation couples with the folding (rearrangements) of the alpha subunit monomer or/and beta subunit dimer.
    • الرقم المعرف:
      0 (Macromolecular Substances)
      0 (Recombinant Proteins)
      7006-34-0 (Asparagine)
      EC 4.2.1.20 (Tryptophan Synthase)
    • الموضوع:
      Date Created: 19960815 Date Completed: 19961104 Latest Revision: 20190620
    • الموضوع:
      20221213
    • الرقم المعرف:
      10.1111/j.1432-1033.1996.0063h.x
    • الرقم المعرف:
      8797836