European Biophysics Journal

, Volume 22, Issue 3, pp 185–194

The influence of the effectors of yeast pyruvate decarboxylase (PDC) on the conformation of the dimers and tetramers and their pH-dependent equilibrium

  • Stephan König
  • Dmitri Svergan
  • Michel H. J. Koch
  • G. Hübner
  • A. Schellenberger
Article

DOI: 10.1007/BF00185779

Cite this article as:
König, S., Svergan, D., Koch, M.H.J. et al. Eur Biophys J (1993) 22: 185. doi:10.1007/BF00185779
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Abstract

The influence of effectors of yeast pyruvate decarboxylase, phosphate, pyruvamide, thiamin diphosphate and Mg++, on the pH-dependent equilibrium between dimers and tetramers was studied by synchrotron radiation X-ray solution scattering. Thiamin diphosphate and phosphate shift the equilibrium to higher pH values without altering the structure of the oligomers. Pyruvamide, a substrate analogue activator, induces a significant change in the structure of the tetramer. By eliminating radiation damage by addition of dithioerythrol to the buffers, the scattering curves could be measured accurately over a large angular range. They were expanded in terms of spherical harmonics to obtain the shapes of the dimers and tetramers with higher resolution than was hitherto possible. This also allowed us to position the dimers, which are centrosymmetric at low resolution, in the tetramers which have 222 symmetry. The results indicate that addition of pyruvamide results in a less compact tetramer owing to structural changes in the dimers and to their displacements.

Key words

Allostery Molecular model Synchrotron radiation Solution scattering Spherical harmonics 

Copyright information

© Springer-Verlag 1993

Authors and Affiliations

  • Stephan König
    • 1
  • Dmitri Svergan
    • 2
  • Michel H. J. Koch
    • 2
  • G. Hübner
    • 1
  • A. Schellenberger
    • 1
  1. 1.Institute of Biochemistry, Department of EnzymologyMartin-Luther-University Halle WittenbergHalleGermany
  2. 2.European Molecular Biology LaboratoryHamburg OutstationHamburgGermany

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