Figure 6.
The built-in lid affects inter-ring communication of group II chaperonins. (a) Nested allosteric coupling in group II chaperonins. Positive cooperativity among the subunits of one ring is nested into negative cooperativity between the two rings. (b,c) The second allosteric transition, occurring at high ATP concentrations, is absent in the lidless chaperonin variants. Initial velocities of ATP hydrolysis by cTRiC (b) and Cpn Δlid (c) were plotted against ATP concentration and fit to equation (2) (see Methods). Each data point shows the average of at least three independent experiments. Error bars represent s.e.m.