title: Isolation and partial characterization of a novel and uncommon two-chain 64-kDa ribosome-inactivating protein from the bark of elder (Sambucus nigra L.).
abstract: A novel, strongly basic, two-chain ribosome-inactivating protein (RIP) with an apparent Mr of 64000 by SDS-PAGE and 63469 by mass spectrometry analysis, that we have named basic nigrin b, has been found in the bark of elder (Sambucus nigra L.). The new protein does not agglutinate red blood cells, even at high concentrations and displays an unusually and extremely high activity towards animal ribosomes (IC50 of 18 pg/ml for translation by rabbit reticulocyte lysates). However, it is inactive against plant and HeLa cells protein synthesis. Our functional and structural data are consistent with a heterodimeric structure for basic nigrin b of the type A-B*, B* being a truncated lectin lacking functional binding domains equivalent to the B (lectin) chain of the type 2 RIP SNA I and nigrin b present also in elder bark.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Valladolid, Spain.
authors.forename: F M
authors.initials: FM
authors.lastname: de Benito
authors.forename: L
authors.initials: L
authors.lastname: Citores
authors.forename: R
authors.initials: R
authors.lastname: Iglesias
authors.forename: J M
authors.initials: JM
authors.lastname: Ferreras
authors.forename: E
authors.initials: E
authors.lastname: Camafeita
authors.forename: E
authors.initials: E
authors.lastname: Méndez
authors.forename: T
authors.initials: T
authors.lastname: Girbés
mesh_terms: D000595:Amino Acid Sequence; D004264:DNA Topoisomerases, Type I / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D006367:HeLa Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D009699:N-Glycosyl Hydrolases / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification* / Q000378:metabolism / Q000494:pharmacology; D054788:Ribosome Inactivating Proteins; D054790:Ribosome Inactivating Proteins, Type 2; D012270:Ribosomes / Q000201:enzymology; D017386:Sequence Homology, Amino Acid; D014197:Trees / Q000737:chemistry*
chemical_list: D010940:Plant Proteins; D054790:Ribosome Inactivating Proteins, Type 2; D009699:N-Glycosyl Hydrolases; D054788:Ribosome Inactivating Proteins; D004264:DNA Topoisomerases, Type I