The quaternary organization and dynamics of the molecular chaperone HSP26 are thermally regulated.
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.
Benesch
Justin L P
JL
Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford, UK.
Aquilina
J Andrew
JA
Baldwin
Andrew J
AJ
Rekas
Agata
A
Stengel
Florian
F
Lindner
Robyn A
RA
Basha
Eman
E
Devlin
Glyn L
GL
Horwitz
Joseph
J
Vierling
Elizabeth
E
Carver
John A
JA
Robinson
Carol V
CV
D002850:Chromatography, Gel; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000378:metabolism; D008027:Light; D019906:Nuclear Magnetic Resonance, Biomolecular; D020836:Protein Structure, Quaternary; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism; D012542:Scattering, Radiation; D013050:Spectrometry, Fluorescence; D021241:Spectrometry, Mass, Electrospray Ionization; D013696:Temperature
C499528:HSP26 protein, S cerevisiae; D006360:Heat-Shock Proteins; D029701:Saccharomyces cerevisiae Proteins