Fluorescence analysis of the lipid binding-induced conformational change of apolipoprotein E4.

摘要: Apolipoprotein (apo) E is thought to undergo conformational changes in the N-terminal helix bundle domain upon lipid binding, modulating its receptor binding activity. In this study, site-specific fluorescence labeling of (S94) and C-terminal (W264 or S290) helices apoE4 by pyrene maleimide acrylodan was employed probe organization behavior N- domains. Guanidine denaturation experiments monitored demonstrated less organized, more solvent-exposed structure compared bundle. Pyrene excimer together with gel filtration chromatography indicated that there are extensive intermolecular helix–helix contacts through apoE4. Comparison increases pyrene-labeled egg phosphatidylcholine small unilamellar vesicles suggests a two-step lipid-binding process; initially...