Fig. 3: Structures of TTYH2 in complex with delipidated APOE.
From: Interactions between TTYH2 and APOE facilitate endosomal lipid transfer
a, Low-resolution 3D reconstruction of TTYH2 in complex with APOE containing a nanogold label shown in two orientations. A slice through the density that defines the position of the gold label located between the two extracellular domains of the dimer is shown on the left. b, Cryo-EM density (4 Å) of detergent-solubilized TTYH2 in complex with delipidated APOE expressed in E. coli. c, Cryo-EM density (3.95 Å) of detergent-solubilized TTYH2 in complex with the delipidated C-terminal domain of APOE (APOE(CTD)) expressed in E. coli. d, Cryo-EM density (4.3 Å) of detergent-solubilized TTYH2 in complex with APOE in an uncontrolled lipidation state obtained after the coexpression of both proteins in HEK293 cells (APOE(CE)). For b–d, The lower resolution of the density of APOE (gold) reflects the high local mobility of the bound protein. e, High-resolution (2.7 Å) structure of TTYH2 obtained by combining particles that did not contain APOE from all datasets reveals its interaction with lipids (yellow) that remained bound during purification. A low-pass-filtered density (right) illustrates the local distortion of the detergent or lipid environment (yellow) reaching into the lipid-filled cavity. f, Magnification of the region surrounding the hydrophobic cavity emerging from the membrane with interacting lipids. The protein is shown as a ribbon. Refined positions of selected lipid molecules are shown as space-filling models. The molecular surface is shown in white. For b–f, the two subunits of TTYH2 are shown in different colours.
