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The low density lipoprotein receptor active conformation of apolipoprotein E. Helix organization in n-terminal domain-phospholipid disc particles.

par Raussens, Vincent ;Fisher, C A;Goormaghtigh, Erik ;Ryan, Robert O;Ruysschaert, Jean Marie
Référence The Journal of biological chemistry, 273, 40, page (25825-25830)
Publication Publié, 1998-10

Article révisé par les pairs

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Résumé :

Lipid association is a prerequisite for receptor interactions of apolipoprotein E (apoE). Disc complexes of the N-terminal 22-kDa apoE3 receptor binding domain and dimyristoylphosphatidylcholine display full receptor binding activity. Studies have been performed to characterize conformational adaptations of the globular, lipid-free four-helix bundle structure that culminate in stable association of its amphipathic alpha-helices with a lipid surface. Helix-lipid interactions in bilayer disc complexes can conceivably adopt two orientations: parallel or perpendicular to the phospholipid acyl chains. Evidence based on infrared dichroism, geometrical arguments, and x-ray crystallography support the view that defined helical segments in the four-helix bundle realign upon lipid association, orienting perpendicular to the phospholipid fatty acyl chains, circumscribing the bilayer disc. Thus, it is likely that paired helical segments align in tandem, presenting a convex receptor-active surface.