Conformational change of chaperone Hsc70 upon binding to a decapeptide: a circular dichroism study.
The conformation of bovine Hsc70, a 70-kDa heat shock cognate protein, and its conformational change upon binding to decapeptides, was studied by CD spectroscopy and secondary structure prediction (Chou, P.Y. & Fasman, G.D., 1974, Biochemistry 13, 222-245). The CD spectra were analyzed by the LINCOMB method, as well as by the convex constraint analysis (CCA) method (Perczel, A., Park, K., & Fasman, G.D., 1992, Anal. Biochem. 203, 83-93). The result of the CD analysis of Hsc70 (15% alpha-helix, 24% beta-sheet, 24% beta-turn, and 38% remainder) was very similar to the predicted secondary structure for the beta-sheet (24%) and the beta-turn (29%). However, there is disagreement between the alpha-helical content by CD analysis (15%) and the predicted structure (30%). In spite of the fact that the decapeptides contained a considerable amount of beta-sheet (22%), the interaction of the heat shock protein with the peptide resulted in an overall decrease in the content of beta-sheet conformation (-15%) of the complex. This may be due to induction of a molten globule state. The result of the CCA analysis indicated that the Hsc70 undergoes a conformational change upon binding the decapeptides.
Park
K
K
Graduate Department of Biochemistry, Brandeis University, Waltham, Massachusetts 02254-9110.
Flynn
G C
GC
Rothman
J E
JE
Fasman
G D
GD
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D018833:Chaperonins; D002942:Circular Dichroism; D006360:Heat-Shock Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry*
D006360:Heat-Shock Proteins; D009842:Oligopeptides; D011506:Proteins; D018833:Chaperonins