Open AccessCharacterization and molecular cloning of two different type 2 ribosome‐inactivating proteins from the monocotyledonous plant Polygonatum multiflorum
Author(s) -
Van Damme Els J. M.,
Hao Qiang,
Charels Diana,
Barre Annick,
Rougé Pierre,
Van Leuven Fred,
Peumans Willy J.
Publication year - 2000
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.2000.01295.x
Subject(s) - ribosome inactivating protein , tetramer , lectin , ricin , biochemistry , biology , affinity chromatography , molecular cloning , microbiology and biotechnology , peptide sequence , rna , ribosome , toxin , gene , enzyme
Leaves of the monocotyledonous plant Polygonatum multiflorum L. (Solomon's seal) contain besides a monocot mannose‐binding lectin two galactose/ N ‐acetylgalactosamine (Gal/GalNAc)‐binding type 2 ribosome‐inactivating proteins (RIPs). Both RIPs were purified using a combination of classical protein purification techniques and affinity chromatography. Although both RIPs consist of protomers of 65 kDa, the P. multiflorum RIP monomer (PMRIPm) occurs as a monomer of approximately 60 kDa, whereas the tetramer (PMRIPt) is a tetramer of 240 kDa. Both RIPs exhibit similar RNA N‐glycosidase activity but differ in their specific agglutination activity and carbohydrate‐binding specificity, PMRIPt being a GalNAc‐specific lectin whereas PMRIPm is Gal/GalNAc‐specific. Toxicity tests indicated that both Polygonatum RIPs exhibit a very low cytotoxicity towards human and animal cells. Analysis of the genomic clones encoding both RIPs revealed a high degree of sequence similarity to other type 2 RIPs. Molecular modelling confirmed that both Polygonatum RIPs have a similar structure to ricin.