Thermally induced structural changes of intrinsically disordered small heat shock protein Hsp22.
We applied different methods (differential scanning calorimetry, circular dichroism, Fourier transform infrared spectroscopy, and intrinsic fluorescence) to investigate the thermal-induced changes in the structure of small heat shock protein Hsp22. It has been shown that this protein undergoes thermal-induced unfolding that occurs within a very broad temperature range (from 27 degrees C to 80 degrees C and above), and this is accompanied by complete disappearance of alpha-helices, significant decrease in beta-sheets content, and by pronounced changes in the intrinsic fluorescence. The results confirm predictions that Hsp22 belongs to the family of intrinsically disordered proteins (IDP) with certain parts of its molecule (presumably, in the alpha-crystallin domain) retaining folded structure and undergoing reversible thermal unfolding. The results are also discussed in terms of downhill folding scenario.
A. N. Bach Institute of Biochemistry, Russian Academy of Sciences, Leninsky Prosp. 33, 119071 Moscow, Russia.
Alexey S
AS
Kazakov
Denis I
DI
Markov
Nikolai B
NB
Gusev
Dmitrii I
DI
Levitsky
D000199:Actins / Q000378:metabolism; D002152:Calorimetry, Differential Scanning; D006360:Heat-Shock Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D006358:Hot Temperature; D006801:Humans; D018832:Molecular Chaperones; D009154:Mutation; D011485:Protein Binding / Q000187:drug effects; D011489:Protein Denaturation; D017510:Protein Folding; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000494:pharmacology; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D038201:alpha-Crystallins / Q000737:chemistry
D000199:Actins; C413214:HSPB8 protein, human; D006360:Heat-Shock Proteins; D018832:Molecular Chaperones; D038201:alpha-Crystallins; D017346:Protein Serine-Threonine Kinases