The quaternary organization and dynamics of the molecular chaperone HSP26 are thermally regulated

Authors

J. L. Benesch, Physical and Theoretical Chemistry Laboratory
Andrew Aquilina, University of Wollongong
Andrew Baldwin, University of Toronto
Agata Rekas, Australian Nuclear Science and Technology Organisation
Florian Stengel, Physical and Theoretical Chemistry Laboratory
Robyn Lindner, Tyrian Diagnostics
Eman Basha, University of Arizona
G. Devlin, Monash University
J. Horwitz, University of California - Los Angeles
Elizabeth Vierling, University of Arizona
John Carver, University of Adelaide
C. V. Robinson, Physical and Theoretical Chemistry Laboratory

RIS ID

33993

Publication Details

Benesch, J. L. P., Aquilina, J. Andrew., Baldwin, A. J., Rekas, A., Stengel, F., Lindner, R. A., Basha, E., Devlin, G. L., Horwitz, J., Vierling, E., Carver, J. A. & Robinson, C. V. (2010). The quaternary organization and dynamics of the molecular chaperone HSP26 are thermally regulated. Chemistry and Biology, 17 (9), 1008-1017.

Abstract

The function of ScHSP26 is thermally controlled: the heat shock that causes the destabilization of target proteins leads to its activation as a molecular chaperone. We investigate the structural and dynamical properties of ScHSP26 oligomers through a combination of multiangle light scattering, fluorescence spectroscopy, NMR spectroscopy, and mass spectrometry. We show that ScHSP26 exists as a heterogeneous oligomeric ensemble at room temperature. At heat-shock temperatures, two shifts in equilibria are observed: toward dissociation and to larger oligomers. We examine the quaternary dynamics of these oligomers by investigating the rate of exchange of subunits between them and find that this not only increases with temperature but proceeds via two separate processes. This is consistent with a conformational change of the oligomers at elevated temperatures which regulates the disassembly rates of this thermally activated protein.