Oxidized Low-Density Lipoprotein-Binding Specificity of the Asp-Hemolysin-Related Synthetic Peptides from Aspergillus fumigatus

Abstract

Oxidatively modified low-density lipoprotein (OxLDL) is present in atherosclerotic lesions and has been proposed to play an important role in atherogenesis. In the present study, in order to clarify the structure-binding activity relationship of Asp-hemolysin-related peptides to OxLDL, we investigated the interaction between Asp-hemolysin-related peptides consisting of 4 to 29 amino acid residues and OxLDL. The incubation of OxLDL with each Asp-hemolysin-related peptide resulted in the formation of an Asp-hemolysin/OxLDL complex. In particular, the tetrapeptide, YKDG (P-4), bound to OxLDL and inhibited the OxLDL-induced macrophage proliferation in a dose-dependent manner. Furthermore, we demonstrated that lysophosphatidylcholine (LysoPC) extracted from OxLDL inhibited the binding of P-21 to OxLDL in a dose-dependent manner and synthetic [¹⁴C]LysoPC bound to P-21. We propose here that the YKDG region is one of the important sites for the binding of these peptides to OxLDL, and LysoPC as a typical lipid moiety of OxLDL is attributed to the binding of OxLDL to these peptides.