Fig. 1: Structure of the yeast Seipin Sei1.

A Cryo-EM map of Sei1 homodecamer shown as (i) side view, depicting protein density (contour level of 0.007) with each Sei1 protomer colored in shades of blue, and the surrounding detergent micelle shown in transparent gray (contour level of 0.005) or (ii) 90-degree rotated view looking down from the cytosol, with detergent micelle omitted for clarity (contour level of 0.007). B Cartoon representation of the Sei1 homodecamer model depicted as (i) side view or (ii) 90-degree rotated view looking down from the cytosol, as depicted in (A). Individual Sei1 protomers are displayed in different shades of blue. C Cartoon of Sei1 protomer model colored as rainbow from N- (blue) to C-(red) termini). The various Sei1 domains are indicated: partial transmembrane helices (TM1 and TM2) capped by the short α3 helix; the luminal β-sandwich (β-strands 1–13); and central helices α1-2. D Structural alignment of the luminal domains of yeast (blue; residues 49–232), fly (residues 88-240 of PDB 6MLU; orange), and human (residues 60–219 of PDB 6DS5; yellow) Seipin protomers. Indicated RMSD is against the yeast protomer. Inset—detail of the luminal helices protruding towards the ER membrane.