The major elderberry (Sambucus nigra) fruit protein is a lectin derived from a truncated type 2 ribosome-inactivating protein |
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| Authors: | Els JM Van Damme Soma Roy Annick Barre Pierre Rougé Fred Van Leuven and Willy J Peumans |
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| Institution: | Laboratory for Phytopathology and Plant Protection, Katholieke Universiteit Leuven, Willem de Croylaan 42, 3001 Leuven, Belgium;Institut de Pharmacologie et Biologie Structurale, UniversitéPaul Sabatier, 35 Chemin des Maraîchers, UPR CNRS 9062, 31062 Toulouse Cedex, France;Center for Human Genetics, Katholieke Universiteit Leuven, Herestraat 49, 3001 Leuven, Belgium |
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| 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. |
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