Ribosome-inactivating proteins in edible plants and purification and characterization of a new ribosome-inactivating protein from Cucurbita moschata.
The basic protein fraction of tissue extracts from 40 edible plants inhibited cell-free protein synthesis and released adenine from herring sperm DNA, thus having adenine glycosylase activity. This suggested the presence of ribosome-inactivating proteins (RIPs) in the plant extracts. This indication was further strengthened by the presence of the two activities after a partial chromatographic purification of three extracts, including that from Lycopersicon esculentum (tomato), which had very low activity. From the extract of Cucurbita moschata (pumpkin), the most active one, a glycoprotein of 30,665 Da was purified which had the properties of a RIP, in that (i) it inhibited protein synthesis by a rabbit reticulocyte lysate with IC50 (concentration giving 50% inhibition) 0.035 nM (1.08 ng ml(-1)) and by HeLa, HT29 and JM cells with IC50 in the 100 nM range, (ii) deadenylated hsDNA and other polynucleotidic substrates, and (iii) depurinated yeast rRNA at a concentration of 0.1 ng ml(-1), all values being comparable to those of other RIPs. The C. moschata RIP gave a weak cross-reaction only with an antiserum against dianthin 32, but not with antisera against other RIPs, and had superoxide dismutase, antifungal and antibacterial activities.
Dipartimento di Patologia sperimentale, Università di Bologna, I-40126 Bologna, Italy.
Luigi
L
Barbieri
Letizia
L
Polito
Andrea
A
Bolognesi
Marialibera
M
Ciani
Emanuele
E
Pelosi
Valentina
V
Farini
Ajay K
AK
Jha
Neelam
N
Sharma
Jorge M
JM
Vivanco
Angela
A
Chambery
Augusto
A
Parente
Fiorenzo
F
Stirpe
D000595:Amino Acid Sequence; D000818:Animals; D000900:Anti-Bacterial Agents / Q000276:immunology / Q000302:isolation & purification* / Q000494:pharmacology; D000935:Antifungal Agents / Q000276:immunology / Q000302:isolation & purification* / Q000494:pharmacology; D002457:Cell Extracts / Q000737:chemistry / Q000494:pharmacology; D003429:Cross Reactions; D028464:Cucurbita / Q000378:metabolism*; D004247:DNA / Q000187:drug effects; D006023:Glycoproteins / Q000276:immunology / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D020128:Inhibitory Concentration 50; D018551:Solanum lycopersicum / Q000378:metabolism; D008969:Molecular Sequence Data; D010940:Plant Proteins / Q000276:immunology / Q000302:isolation & purification / Q000494:pharmacology*; D014176:Protein Biosynthesis / Q000187:drug effects*; D012335:RNA, Ribosomal / Q000187:drug effects; D011817:Rabbits; D054789:Ribosome Inactivating Proteins, Type 1; D012270:Ribosomes / Q000187:drug effects*
D000900:Anti-Bacterial Agents; D000935:Antifungal Agents; D002457:Cell Extracts; D006023:Glycoproteins; D010940:Plant Proteins; D012335:RNA, Ribosomal; D054789:Ribosome Inactivating Proteins, Type 1; D004247:DNA