Extended Data Fig. 7: Cryo-EM reconstruction summary and validation.

a. Warp³⁶-denoised K3 micrograph of vitrified ^ΔN40P-Rex1^{T4L,Δ1119-1211}. Representative micrograph from a dataset of 9597 movies. b. RELION³⁴ 2D class averages (no alignments) after particle polishing. c. Comparison of 2D class averages between autoinhibited P-Rex1 (without T4L, ^ΔN40P-Rex1^{Δ1119-1211, Δ990-1007}), P-Rex1 (with T4L, ^ΔN40P-Rex1^{T4L,Δ1119-1211}), and a single class from the previously published P-Rex1:Gβγ dataset (EMPIAR 10285)¹⁵ showing all three constructs form an equivalent closed domain conformation. d. Final composite reconstruction coloured according to local resolution as estimated by windowed FSC with 0.5 threshold criterion. e. Local resolution histogram showing distribution for both localised refinements and the consensus. f. Angular distribution of final reconstruction and corresponding views (left). g. Gold-standard Fourier Shell Correlation curves of independent half-maps (masked, unmasked, noise substitution corrected, and phase randomised) for both the C-terminal and N-terminal localised reconstructions. h. As in (g) for the full consensus reconstruction.