Binding of C-reactive protein to chromatin and nucleosome core particles. A possible physiological role of C-reactive protein.
By using a variety of biochemical techniques, chromatin and chromatin fragments have been identified as probable physiological ligands for C-reactive protein. Studies using 14C-labeled C-reactive protein show that binding to chromatin is saturable with a Kd = 8 X 10(-7) M, a value indicating that the affinity of C-reactive protein for chromatin is at least four times its affinity for phosphorylcholine. At saturation, there is approximately one C-reactive protein-binding site for every 160 base pairs of DNA in chromatin. The interaction of C-reactive protein with chicken erythrocyte nucleosome core particle has been studied. Fifty per cent inhibition of the binding of C-reactive protein to phosphorylcholine is obtained at a core particle concentration of 1.25 X 10(-9) M, indicating that the affinity of C-reactive protein for one of the sites on core particles is at least 2400 times greater than the affinity of C-reactive protein for phosphorylcholine. The possibility that C-reactive protein may act as a scavenger for chromatin fragments released from damaged cells is discussed.
D000818:Animals; D002097:C-Reactive Protein / Q000502:physiology*; D002843:Chromatin / Q000378:metabolism*; D004247:DNA / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005347:Fibroblasts / Q000378:metabolism; D005779:Immunodiffusion; D007700:Kinetics; D008168:Lung / Q000378:metabolism; D009707:Nucleosomes / Q000378:metabolism*; D010587:Phagocytosis; D010713:Phosphatidylcholines / Q000378:metabolism; D011817:Rabbits; D012867:Skin / Q000378:metabolism
D002843:Chromatin; D009707:Nucleosomes; D010713:Phosphatidylcholines; D002097:C-Reactive Protein; D004247:DNA