Fig. 2: MD simulation reveals protein-specific heterogeneity of membrane curvature.

Snapshots of the chromatophore vesicle at the beginning (A) and after 500 ns (B) of the MD simulation. The membrane is nearly flat in the vicinity of the bc₁ complexes [magenta] but convex near other proteins (also see Figs. S8 and S10). (Insets) Zoom-in view of two proximal bc₁ complexes that are found to induce the highest degree of local membrane curvature change. Tilt-angle, θ, between these two proximal bc₁ complexes decrease during the simulation, reflecting a gradual increase in the local radius of curvature (tilt angle-radius of curvature relationship discussed in Supplementary Method 7: Eq. 3). Dotted-line indicates the radius of the membrane vesicle at the beginning of the MD simulation (see Fig. S6c). (C) Flat-to-convex curvature in the vicinity of the bc₁ complexes observed in the all-atom (AA) and coarse-grained (CG) MD simulations; phosphate head-groups of POPE, POPG, POPC are labeled as red, green and blue beads respectively. (D) 2D-Mollweide projection map of the chromatophore vesicle annotated with the locations of all four membrane protein types. (E) (upper panels) Mollweide maps of the chromatophore membrane illustrating the radial distances of its atoms to the vesicle’s center of mass at 0, 250 and 500 ns of the AA MD simulation. The distance is the highest for the ATP synthase motors that protrude the most, the smallest for the bc₁-rich areas, and almost uniform across the rest of the chromatophore membrane. (lower panels) Local radius of curvature obtained at every point on the chromatophore membrane derived with a 2-D curve fitting protocol (Supplementary Method 7: Eqs. 1–2) at 0, 250 and 500 ns of AA MD. The radius of curvature is uniform across the chromatophore membrane, except for the bc₁-rich patches where the membrane is considerably flatter, and the radius exceeds 500 Å.