Glycosphingolipid N-linked acyl chain binding in GLTP crystal structures.

(A) To the left bound C18:1-GlcCer, C18:0-LacCer and ganglioside GM3 lipids in the sphingosine-in conformation found in the crystal structures of different GLTPs (3S0K, 1SX6 and 2BV7 respectively). On the right is bound 12:0-di-sulfatide, C12:0-sulfatide and C12:0-LacCer in the sphingosine-out conformation found in the crystal structures of different GLTPs (4GIX, 4H2Z and 2EVD respectively). The middle lower picture shows bound C24:1-sulfatide, C18:2-GalCer and C24:1-GalCer in the crystallized GLTP structures 3RZN, 2EVL and 2EUK respectively. The carbohydrate head groups are shown in white, sphingosine chains in red, and the N-linked acyl chains in blue. The sphingolipids all fit into the GLTP hydrophobic cavity in a similar manner, with a special kink area (black circle) where the N-linked acyl chains bend. (B) GLTP crystal structure (FFAT-like domain in blue) with bound C8:0-LacCer in the sphingosine-out conformation (PDB ID, 2EUM), (C) GLTP with bound C12:0-LacCer in the sphingosine-out conformation (PDB ID, 2EVD), (D) GLTP with bound C18:1-GlcCer in the sphingosine-in conformation (PDB ID, 3S0K), and (E) GLTP with bound C24:1-GalCer in the sphingosine-out conformation (PDB ID, 2EUK).