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spherical membrane vesicles, the photosynthetic chromato- their curvature properties: although LH2s induce isotropicphores, that house these proteins (6). The mechanisms by which LH1 and LH2 shape the photo-synthetic membrane were found to differ from each other (6). LH1, in complex with the reaction center (RC) and an addi-tional polypeptide at an undetermined location (7–14), PufX, forms an S-shaped (RC-LH1-PufX)2 dimeric complex that measures ~200 A ̊ along the long dimer axis and 100 A ̊ along the short dimer axis (Fig. 1). A modeled RC-LH1-PufX dimer placed in a membrane developed a bend at its dimeriz-ing interface in an all-atom simulation within 20 ns, forcing the surrounding membrane to adapt to the dimer’s shape and curvature and form spherical vesicles, RC-LH1-PufX dimers induce anisotropic curvature and form cylindrical tubes as seen in Rba. sphaeroides mutants lacking LH2 (8,15–19). This difference in directionality was also observed in th