Figure 3.

A subset of the ΔΔG^‡ surface when tensile and compressive forces are applied along the ribosome exit tunnel axis. (a) ΔΔG^‡ surface in the region φ ∈ [−186°, −174°] × θ ∈ [84°, 96°], representing the directions in which compressive forces are applied. (b) Directions of the tensile forces (blue arrow and cone) and compressive forces (red arrow and cone) applied respectively parallel and antiparallel along the exit tunnel axis. The PTC is represented in the same manner as in Figure 1b, except that the most probable transition state structure is shown. The cones represent 6° off axis from the arrows. (c) ΔΔG^‡ surface on the region φ ∈ [−6°, 6°] × θ ∈ [84°, 96°], representing the tensile forces applied along the exit tunnel. Panels a and c have the same colormap as used in Figure 2b but have a smaller range. Note that while the tensile force lowers the activation barrier by a statistically significant amount, the compressive force does not result in a statistically significant change in barrier height.