Characterization and Molecular Cloning of Sambucus nigra Agglutinin V (Nigrin b), A Galnac‐specific Type‐2 Ribosome‐Inactivating Protein from the Bark of Elderberry ( Sambucus nigra )
1996; Wiley; Volume: 237; Issue: 2 Linguagem: Inglês
10.1111/j.1432-1033.1996.0505k.x
ISSN1432-1033
AutoresEls J. M. Van Damme, Annick Barre, Pierre Rougé, Fred Van Leuven, Willy J. Peumans,
Tópico(s)Transgenic Plants and Applications
ResumoThe molecular structure of the Sambucus nigra agglutinin V (SNAV), which has been described previously as a type‐2 ribosome‐inactivating protein called nigrin b, has been studied in detail by analysis of the purified protein combined with cDNA cloning and molecular modelling. Native SNAV is a dimer of two [A‐s‐s‐B] pairs. Hapten inhibition assays indicated that GalNAc is a 20‐fold more potent inhibitor of SNAV than Gal. A cDNA clone encoding SNAV was isolated from a cDNA library constructed with mRNA from the bark. Sequence analysis of this cDNA revealed a striking similarity to the recently cloned NeuAc α‐2,6‐gal/GalNAc‐specific S. nigra bark agglutinin I (SNAI) and to the previously sequenced type‐2 ribosome‐inactivating proteins from Ricinus communis and Abrus precatorius. In addition, molecular modelling of SNAV further suggested that its structure closely resembles that of ricin. The N‐terminal sequence of the B chain of SNAV also shows a marked similarity with the polypeptide of the previously described GalNAc‐specific S. nigra bark agglutinin II (SNAII), which unlike SNAV and SNAI has no ribosome‐inactivating activity. It appears, therefore, that elderberry bark contains at least two different type‐2 ribosome‐inativating proteins and a lectin built up of subunits which are closely related to the B chain of SNAV.
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