A slice through a filtered tomogram showing SR vesicles in contact with a putative T‐tubule. Individual RyR1 molecules are indicated by the red circles. The dense protein coat on the surface of the SR vesicles corresponds to the SERCA pump. Areas circled in yellow indicate accumulation of density inside the SR. Scale bar: 20 nm.
A slice through the structure of RyR1 in contact with putative TT membrane.
A middle slice through the in situ structure of RyR1 at 12.6‐Å resolution. The observed additional transmembrane density is indicated by the red arrows. Scale bars in B, C: 10 nm.
Slice through the structures of apoRyR1 with the putative TT membrane (left) and the standalone apoRyR1 (right, with the flipped handedness and reduced resolution for comparison) 22 Å away from the middle slice (Y = 92 in the volume coordinates). Scale bar: 10 nm.
Volume‐rendered visualizations of the average structure of RyR1 with the RyR1 atomic model fit (PDB: 5TB2). The left panel is a thin section through the centre of the volume.
The location of the CaM/S100A1 binding site is marked with red circles in slices through maps of the in situ structure (left) and the single‐particle structure (EMDB: 8393) in the same orientation as the in situ structure and filtered to 15 Å (right). Scale bar: 10 nm.
The in situ structure with an atomic model (PDB: 5TB2) fitted showing an unaccommodated density. Red circles are sites of potential interaction between RyR1 and the regulatory proteins.