title: A new pentraxin (serum amyloid P-component) in the rat: evidence for two quaternary structures and effect of ligands on self-association.
abstract: A new rat serum protein has been isolated by affinity chromatography using ethanolamine- or phosphoethanolamine-substituted agarose gels. This protein has the morphological and functional characteristics of serum amyloid P-component and C-reactive protein. It comprises C5 cyclic symmetry structure with non covalently cross-linked subunits which have calcium-dependent binding sites. We have called this protein rat serum amyloid P-component since it has all the properties typical of human serum amyloid P-component: it is made up to 10 subunits, it contains sialic acid and hexoses, it forms macroscopic polymers and its does not precipitate with pneumococcal C-polysaccharide. Rat amyloid P-component has three remarkable properties. Electron microscopy has shown that apart from pentagonal figures and stacked discs, rat P-component has a C10 cyclic symmetry structure. Rat amyloid P-component has an affinity for specific ligands, such as phosphorylcholine or phosphoethanolamine. These ligands are able to depolymerize self-associated rat P-component. With these characteristics, rat serum amyloid P-component could prove to be an important model in the study of the relations between amyloid P-component and amyloidosis.
mesh_terms: D000682:Amyloid / Q000097:blood / Q000302:isolation & purification*; D000818:Animals; D002846:Chromatography, Affinity; D004587:Electrophoresis, Agar Gel; D004591:Electrophoresis, Polyacrylamide Gel; D007123:Immunoelectrophoresis, Two-Dimensional; D046911:Macromolecular Substances; D008297:Male; D008854:Microscopy, Electron; D008970:Molecular Weight; D051381:Rats; D011919:Rats, Inbred Strains; D000683:Serum Amyloid P-Component
chemical_list: D000682:Amyloid; D046911:Macromolecular Substances; D000683:Serum Amyloid P-Component