Structure and mechanism of a eukaryotic ceramide synthase complex

A

Overall structure of a Lac1‐Lip1 heterodimer. The two interaction interfaces between Lac1 and Lip1, namely the TM interaction interface and the luminal interaction interface, are highlighted with gray and red boxes, respectively.

B, C

Detailed views of the TM interaction interface between Lac1 and Lip1 (B) and the luminal interaction interface between Lac1 and Lip (C). All potential polar interactions are displayed by red dashed lines.

D

Functional characterization of Lip1 residues at the luminal interaction interface between Lac1 and Lip1 by CerS activity. Each data point is the average ± SEM of three independent experiments.

E

Structural superposition of the Lac1‐Lip1^WT heterodimer (colored based on the subunits and domains) and the Lac1‐Lip1^S74F heterodimer (colored light gray).

F

Collapse of the C26 acyl chain binding tunnel within Lac1 in the Lac1‐Lip1^S74F mutant structure.

G

Local conformational changes of residues lining the C26‐CoA binding site in the Lac1‐Lip1^S74F mutant structure.

Figure 4. Interactions between Lac1 and Lip1.