title: The major elderberry (Sambucus nigra) fruit protein is a lectin derived from a truncated type 2 ribosome-inactivating protein.
abstract: The major protein of elderberry (Sambucus nigra L.) fruits is a lectin, called Sambucus nigra agglutinin IVf or SNAIVf. This lectin is composed of subunits that strongly resemble the B chain of the type 2 ribosome-inactivating protein (RIP), called SNAVf, present in the same tissue. To corroborate the possible relationship between both proteins their corresponding cDNAs were cloned and compared. Alignment of the deduced amino acid sequences revealed that the cDNA encoding SNAIVf is almost identical to that of SNAVf except that its A chain is truncated. Northern blot analysis confirmed that the mRNA encoding SNAIVf is about 500 nucleotides shorter than the SNAVf mRNA. In addition, the occurrence of a truncated type 2 RIP gene was unambiguously demonstrated by the analysis of PCR amplified genomic sequences. These results not only demonstrate for the first time that a plant lectin is encoded by a truncated type 2 RIP gene but also address important questions with respect to the molecular evolution of RIP and lectins.
authors.affiliation: Laboratory for Phytopathology and Plant Protection, Katholieke Universiteit Leuven, Belgium. els.vandamme@agr.kuleuven.ac.be
authors.forename: E J
authors.initials: EJ
authors.lastname: Van Damme
authors.forename: S
authors.initials: S
authors.lastname: Roy
authors.forename: A
authors.initials: A
authors.lastname: Barre
authors.forename: P
authors.initials: P
authors.lastname: Rougé
authors.forename: F
authors.initials: F
authors.lastname: Van Leuven
authors.forename: W J
authors.initials: WJ
authors.lastname: Peumans
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005638:Fruit / Q000378:metabolism*; D015723:Gene Library; D007438:Introns; D037102:Lectins / Q000096:biosynthesis* / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009699:N-Glycosyl Hydrolases; D037121:Plant Lectins; D010940:Plant Proteins / Q000378:metabolism*; D018547:Plant Stems; D017433:Protein Structure, Secondary; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry; D054788:Ribosome Inactivating Proteins; D054790:Ribosome Inactivating Proteins, Type 2; D012276:Ricin / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D018076:DNA, Complementary; D037102:Lectins; D037121:Plant Lectins; D010940:Plant Proteins; D011994:Recombinant Proteins; D054790:Ribosome Inactivating Proteins, Type 2; C050600:Sambucus nigra lectins; D012276:Ricin; D009699:N-Glycosyl Hydrolases; D054788:Ribosome Inactivating Proteins