Extended Data Fig. 4: Atomic modelling of Ste2 structures in the cryo-EM density maps.
From: Activation mechanism of the class D fungal GPCR dimer Ste2
a-d, Densities were visualized using UCSF ChimeraX36 and encompass a carve radius of 2 Å around the indicated region. Density maps and models are shown for all seven transmembrane helices of Ste2•Ant (contour level 0.024), Ste2•LF (contour level 0.62), Ste2•AgIL (contour level 0.6 for TM1-TM6 and 0.49 for TM7), and Ste2•AgAL (contour level 0.6 for TM1-TM6 and 0.49 for TM7), respectively. e, Densities for intracellular and extracellular loops (ICL and ECL) 1, 2 and 3 are shown for the indicated structures. Ste2•Ant is contoured at 0.0125 (except ECL1 contoured at 0.02). Ste2•LF is contoured at 0.3 (except ICL1 contoured at 0.45 and ECL1 contoured at 0.6). Ste2•AgIL is contoured at 0.4 (except ECL1 and ECL2 contoured at 0.6). Ste2•AgAL is contoured at 0.6 (except ICL2 and ICL3 contoured at 0.4). f, Densities for antagonistB (contour level 0.022), α-factorB in Ste2•AgIL (contour level 0.6) and α-factorB in Ste2•AgAL (contour level 0.9) are shown as a mesh. g, A belt of putative CHS molecules surrounding Ste2•Ant are shown along with modelled ordered water molecules (contour level 0.018). h, Densities for N-acetylglucosamine molecules attached to Asn25 and Asn32 of Ste2A and Ste2B were present in all cryo-EM maps, and representative densities from Ste2•Ant are shown (contour level 0.015). Asn25 and Asn32 are well-characterized N-glycosylation sites in Ste21,71. i, Densities for N-terminal domain and TM1 dimer interface are shown for Ste2•Ant (contour level 0.04), Ste2•LF (contour level (contour level 0.62), Ste2•AgIL (contour level 0.7), and Ste2•AgAL (contour level 0.7). j, Model versus Map Fourier shell correlation (FSC) curves obtained from validation of atomic models against cryo-EM maps are shown. At FSC = 0.5, model resolutions were 2.9 Å, 3.3 Å, 3.8 Å, and 3.7 Å for Ste2•Ant, Ste2•LF, Ste2•AgIL and Ste2•AgAL, respectively.
