Interaction of C-reactive protein with artificial phosphatidylcholine bilayers.
C-Reactive protein (CRP), the most characteristic of the 'acute phase proteins' (ref. 1) is thought to participate in the mediation and/or modulation of acute inflammatory processes, but its exact function is unknown. CRP has a Ca2+-dependent binding specificity for phosphorylcholine, the polar head group of two widely distributed lipids, lecithin (phosphatidylcholine, PC) and sphingomyelin (SM). A number of observations suggest that at least some of the biological activities of CRP depend on its interaction with phospholipids of cell membranes. In addition, interaction of CRP with PC- and SM-containing lipid dispersions and with PC-containing liposomes can activate the complement system. We report here that binding of CRP to model membranes of PC requires the incorporation into the bilayer of lysophosphatidylcholine (LPC). Thus, a disturbance of the molecular organisation of the bilayer appears to be necessary for binding of CRP. These findings provide a possible biochemical explanation for binding of CRP to damaged but not intact cell membranes and might be relevant to its biological function.
D001665:Binding Sites; D002097:C-Reactive Protein; D003902:Detergents; D008081:Liposomes; D008244:Lysophosphatidylcholines; D008567:Membranes, Artificial; D010713:Phosphatidylcholines; D010767:Phosphorylcholine; D013329:Structure-Activity Relationship
D003902:Detergents; D008081:Liposomes; D008244:Lysophosphatidylcholines; D008567:Membranes, Artificial; D010713:Phosphatidylcholines; D010767:Phosphorylcholine; D002097:C-Reactive Protein