Characterization and molecular cloning of two different type 2 ribosome-inactivating proteins from the monocotyledonous plant Polygonatum multiflorum.
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.
Van Damme
E J
EJ
Laboratory for Phytopathology and Plant Protection, Katholieke Universiteit Leuven, Belgium. Els.VanDamme@agr.kuleuven.ac.be
Hao
Q
Q
Charels
D
D
Barre
A
A
Rougé
P
P
Van Leuven
F
F
Peumans
W J
WJ
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D018548:Cotyledon; D018076:DNA, Complementary; D037102:Lectins / Q000737:chemistry / Q000302:isolation & purification; D019668:Liliaceae / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010802:Phylogeny; D037121:Plant Lectins; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D037102:Lectins; D037121:Plant Lectins; D010940:Plant Proteins