Figure 4.

Effect of Mn²⁺ ions on GroEL/GroES-mediated refolding of mtMDH. The time-dependent reactivation of GroEL-bound mtMDH (4 μM GroEL, 0.3 μM mtMDH) was measured in the presence of 1 mM ATP and an ATP-regeneration system [equimolar (4 μM) GroES] in folding buffer as in Figs. 1–3 but with a near-limiting 6 mM concentration of divalent ions instead of 20 mM Mg²⁺. Open symbols: 6 mM Mg²⁺. Filled symbols: 4 mM Mg²⁺ and 2 mM Mn²⁺. A 6.25-fold excess of free GroEL (22 μM) was added 11 min after initiation of reactivation at 25°C with (○, ▴) or without (□, ♦) ATP added to the reaction.