Figure 2.

Agave activases are highly thermostable. A, The activase isoforms were incubated for 10 min at the indicated temperature, and subsequently the remaining ATPase activity was assayed at 25°C (5 µm protomer). B, ATPase activity of OsRcaβ and AtRcaβ at various temperatures. Proteins were preincubated (10 min) and subsequently measured at the indicated temperatures under the conditions described in Figure 1C. Error bars show mean and sd of independent experiments with n indicated on top of the bars. Significant differences between activities at the same temperature (P < 0.05) are denoted by different letters at the base of each bar. C, AtRcaβ has higher Rubisco activase activity than OsRcaβ even at low temperature. Rubisco activation assays were performed as in Figure 1B at 15°C. A and C, error bars indicate mean and sd of independent experiments (n = 3–5).