Expression and analysis of heparin-binding regions of the amyloid precursor protein of Alzheimer's disease

Deletion mutagenesis studies have suggested that there are two domains within APP which bind heparan sulphate. These domains have been cloned and expressed in the yeast Pichia pastoris. Both recombinant proteins bound to heparin. One domain (APP316–447) was further characterised by binding studies with peptides encompassing this region. Peptides homologous to APP316–346 and APP416–447 were found to bind heparin. Circular dichroism studies show that APP416–447 shifted towards an α-helical conformation in the presence of heparin. This study suggests that heparin-binding domains may lie within regions high in α-helical structure.