Sub-micellar phospholipid accelerates amyloid formation by apolipoprotein C-II

Lipid-free human apolipoprotein C-II (apoC-II) forms amyloid fibrils with characteristic beta -structure, This conformation is distinct from the alpha -helical fold of lipid-bound apoC-II, We have investigated the effect of the short-chain phospholipid, dihcxanoylphosphatidylcholine (DHPC) on amyloid formation by apoC-II, The alpha -helical content of apoC-II increases in the presence of micellar DHPC (16 mM) and amyloid formation is inhibited. However, at sub-micellar DHPC concentrations (below 8 mM) amyloid formation is accelerated 6 fold. These results suggest that individual phospholipid molecules in vivo may exert significant effects on amyloid folding pathways. (C) 2001 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.