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

Lipid-free human apolipoprotein C-II (apoC-II) forms amyloid fibrils with c haracteristic beta -structure, This conformation is distinct from the alpha -helical fold of lipid-bound apoC-II, We have investigated the effect of t he short-chain phospholipid, dihcxanoylphosphatidylcholine (DHPC) on amyloi d 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. H owever, at sub-micellar DHPC concentrations (below 8 mM) amyloid formation is accelerated 6 fold. These results suggest that individual phospholipid m olecules 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.