Figure 5.

Rotation of a mutant F₁(βE190D). [ATP] = 2 mM. (A) Time courses of rotation at 0.1 and 40 MPa, respectively. (B) Histograms of the angle from traces in A at 0.1 (upper) and 40 MPa (lower). Each pair of two peaks was fitted by a sum of two Gaussian curves to determine the peak positions and area intensities. Arrows indicate major peaks at every pair. (C) Histogram of the angular distance, Δθ, between the emerging angle position at 40–60 MPa (θ₂) and the nearest catalytic angle position on the minus direction side at 0.1 MPa (θ₁). The peak angle was 45 ± 9° (mean ± SD, n = 36). (D) Fraction of area intensity of left (circles) and right peaks (squares) (mean ± SD). Each peak intensity was obtained from the angular histograms as shown in C. (E) Ratio of catalytic angle position to binding angle position. (F) Rotational rate as a function of pressure (mean ± SD, n = 25–47, total = 217). The plots in E and F were fitted by k_p-dep/k_p-ind and Eq. 2, respectively, with k_p-ind = 2.5 ± 0.7 s⁻¹, k₀ = 4.0 ± 1.9 s⁻¹, and ΔV^‡ = +100 ± 30 Å³. To see this figure in color, go online.