The lysine cluster in the collagen-like domain of the scavenger receptor provides for its ligand binding and ligand specificity.

Scavenger receptors bind modified low-density lipoproteins (LDL) on a collagen-like domain which possesses a lysine cluster at the carboxy end. We previously constructed a receptor model peptide containing the lysine cluster. In the present study, we evaluated the ligand specificity of the receptor model peptide. It selectively bound modified-LDLs, and not LDL. The binding of acetylated-LDL (Ac-LDL) was inhibited by dextran sulfate, fucoidan, and sulfatides in a manner similar to that of the natural receptor. Both polyguanylic and polyinosinic acids inhibit the Ac-LDL binding whereas polycytidylic acid did not. These results indicate that the lysine cluster in the collagen-like domain has important roles in both ligand binding and ligand specificity.