Demonstration of calcium-induced conformational change(s) in C-reactive protein by using monoclonal antibodies.
Three out of four anti-C-reactive protein monoclonal antibodies [HB3-2, (micro, k)], EA4-1 (gamma 2a, k) and FB2-1 (gamma 1, k) bind to C-reactive protein in the presence of 2.5 mM Ca2+ but not in the presence of 1.0 mM EDTA, indicating that the conformation of the antigenic determinant(s) recognized by these three antibodies is dependent upon Ca2+. This Ca2+-dependent binding can be inhibited by 1.0 mM phosphocholine, indicating that this antigenic determinant is at or near the phosphocholine-binding site of C-reactive protein. The binding of the fourth monoclonal antibody [HD2-4 (gamma 2-k)] is independent of the presence of Ca2+ and is not inhibited by phosphocholine. HB3-2 (micro, k) recognizes an antigenic determinant on the structurally related proteins, rabbit CRP and serum amyloid P.
D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D002097:C-Reactive Protein / Q000276:immunology; D002118:Calcium / Q000494:pharmacology*; D003429:Cross Reactions; D004492:Edetic Acid / Q000494:pharmacology; D000939:Epitopes; D007074:Immunoglobulin G / Q000276:immunology; D010767:Phosphorylcholine / Q000494:pharmacology; D011487:Protein Conformation / Q000187:drug effects
D000911:Antibodies, Monoclonal; D000939:Epitopes; D007074:Immunoglobulin G; D010767:Phosphorylcholine; D002097:C-Reactive Protein; D004492:Edetic Acid; D002118:Calcium