Fig. 4. Structure of RyR1 in native membranes at subnanometer resolution.

a A slice through a tomogram of native SR vesicles extracted from rabbit skeletal muscle. Red circles highlight RyR1 particles on the membrane of SR vesicles. Scale bar: 50 nm. b Slices through a subtomogram average generated from 2715 particles at a resolution of 12.9 Å. c Slices though a refined map at 9.1 Å resolution generated from 2563 particles. Scale bars in b, c: 10 nm. d Corresponding FSC curves between the respective independently processed half-sets. e A volume rendered visualization of the transmembrane domain of the refined map of RyR1 with a rigidly fit atomic model (PDB ID: 5TB2 from reference⁴³).