Characterization of CP86-C4 samples treated with oxidized glutathione.

CP86-C4 was treated with oxidized glutathione as outlined in Materials and Methods. A. SDS-PAGE analysis of CP86-C4 samples in the absence of 2-mercaptoethanol, which shows a shift in gel position caused by formation of an intramolecular disulfide bond. B. Gdn-HCl unfolding profiles of wild type GroEL (open circles), GroEL CP86 (closed circles), and oxidized GroEL CP86-C4 (closed squares) monitored by the CD signal at 222 nm. GroEL was incubated in HEPES-KOH buffer, pH 7.8, containing 10 mM KCl, 5 mM magnesium acetate, and the indicated concentration of Gdn-HCl for 2 h at 25°C prior to measurement. A JASCO J-820 spectropolarimeter was used to measure the CD signal.