Extended Data Fig. 3: MRAS SWI/SWII loops adopt a closed conformation.

a. MRAS shifts towards a closed conformation in the ternary complex. Zoom in of SWI and SWII region of bound MRAS-GppNHp (grey) aligned with apo MRAS-GppNHp (teal pdb: 1x1s). Movement of SWII F74 from unbound open (teal) to closed bound (pale green) is illustrated. SWI of bound MRAS is shown in pink. b. Bound MRAS SWI (pink) exhibits a closed conformation similar to active NRAS (purple, pdb: 5uhv). MRAS SWII (pale green) is conformationally shifted relative to NRAS-GppNHp as well. Movement of SWII F74 from NRAS counterpart Y64 is shown. MRAS-GppNHp is shown in grey. c. Cutout view of the water network mediated by critical residues: PP1C R188 and MRAS SWI E47, D48 and S49 mediate a coordinated network that connects all subunits of the complex.