C-reactive protein binds to the 3beta-OH group of cholesterol in LDL particles.

C-reactive protein (CRP) has been suggested to contribute to the development of atherosclerosis. We previously found binding of CRP to cholesterol in modified low density lipoprotein (LDL) particles. Here, we characterize the interaction between CRP and cholesterol in more detail. When lipids of native LDL were separated by thin-layer chromatography, CRP bound only to cholesterol. When various cholesterol analogues were compared for their ability to bind CRP, we found that any modification of the 3beta-OH group blocked binding of CRP to cholesterol. Similarly, enrichment of LDL with cholesterol but not with its analogues triggered the binding of CRP to LDL. Finally, with the aid of anti-CRP monoclonal antibodies and by molecular modeling, we obtained evidence for involvement of the phosphorylcholine-binding site of CRP in cholesterol binding. Thus, CRP can bind to cholesterol, and the interaction is mediated by the phosphorylcholine-binding site of CRP and the 3beta-hydroxyl group of cholesterol.