FIGURE 3.

Arrhenius analysis of the ATPase activity of the deletion mutants. ATPase activities were measured at different temperatures (25–50 °C) and were calculated as turnover rates (k_cat, in s^-1). From the negative slope of the regression lines, the activation energy, E_a, of the rate-limiting step of the overall reaction can be determined (see Table 3). Filled circles, wild-type PS3 ATP synthase; open circles, Δ³⁸⁰LQDI³⁸³ deletion mutant; filled squares, Δ³⁸⁴IAIL³⁸⁷; open squares, Δ³⁸⁸GMDE³⁹¹; filled triangles, Δ³⁹²LSD³⁹⁴; open triangles, Δ³⁸¹QDIIAIL³⁸⁷.