title: RNP, Sm and SS-B antigens from calf thymus: molecular stability upon enzymatic digestion.
abstract: RNP, Sm and SS-B nuclear antigens from calf thymus were studied with respect to the size distribution on sucrose gradients as well as to the molecular integrity and related structural changes when they were subjected to enzymatic digestions under different conditions. Making a difference with RNP particles, the Sm size distribution is concentration dependent, a property in accordance with the complexity of the Sm particles in comparison with the RNPs. The use of combined effects of temperature, endogenous proteases and RNase A, allowed us to gain insight into the limits of stability of the three antigenic particles. Following treatments in the absence of RNAse A, the degradation products (32-38 Kd molecular weight) of the 70 Kd RNP polypeptide remain stable and associated with other molecules within the RNP particle. It was also found that the phosphate groups of the SS-B protein moiety are only accessible to alkaline phosphatase if the RNA of the SS-B particle is degraded by the action of RNAse A.
authors.affiliation: Institut de Biologia de Barcelona, C.S.I.C., Spain.
authors.forename: M D
authors.initials: MD
authors.lastname: Boleda
authors.forename: M
authors.initials: M
authors.lastname: Bach
authors.forename: N
authors.initials: N
authors.lastname: Durán
authors.forename: J
authors.initials: J
authors.lastname: Palau
mesh_terms: D000818:Animals; D001324:Autoantigens / Q000737:chemistry* / Q000276:immunology; D002417:Cattle; D002467:Cell Nucleus / Q000737:chemistry / Q000276:immunology; D002499:Centrifugation, Density Gradient; D004591:Electrophoresis, Polyacrylamide Gel; D010450:Endopeptidases; D006868:Hydrolysis; D015151:Immunoblotting; D008970:Molecular Weight; D011506:Proteins / Q000737:chemistry; D012259:Ribonuclease, Pancreatic; D012261:Ribonucleoproteins; D017411:Ribonucleoproteins, Small Nuclear; D013696:Temperature; D013950:Thymus Gland / Q000737:chemistry* / Q000276:immunology; D055517:snRNP Core Proteins; D000097585:SS-B Antigen
chemical_list: D001324:Autoantigens; D010450:Endopeptidases; D011506:Proteins; D012259:Ribonuclease, Pancreatic; D012261:Ribonucleoproteins; D017411:Ribonucleoproteins, Small Nuclear; D055517:snRNP Core Proteins; D000097585:SS-B Antigen