Circular Dichroism Measurements on C‐Terminal Fragment of Heat Shock Protein from Rat

The secondary structure of the C‐terminal fragment (10 kDa) of rat hsc70 (a. a. #546–646) was analyzed according to circular dichroism spectra. In the pH range 5–9 and at concentrations of Na+ up to 0.18 M, the protein is estimated to contain 32‐34% a helix, 18–16% of β sheet, approximately 25% for both turns and disordered structures. This protein is most stable at pH between 6 and 7 in solution with 0.055 M Na + concentration. However, all T m are relatively large (57–73 °C) and alterations from one condition to another are small. Thus, the C‐fragment (10 kDa) of hsc70 is a stably folded protein under physiological conditions.