scholarly journals Ribosome-inactivating proteins from plant cells in culture

1989 ◽  
Vol 257 (3) ◽  
pp. 801-807 ◽  
Author(s):  
L Barbieri ◽  
A Bolognesi ◽  
P Cenini ◽  
A I Falasca ◽  
A Minghetti ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Phytolacca Americana ◽  
Pokeweed Antiviral Protein ◽  
Antiviral Protein ◽  
Ribosome Inactivating Protein ◽  
Intact Cells ◽  
Ribosome Inactivating Proteins ◽  
Reticulocyte Lysate ◽  
Ic50 Concentration

1. Ribosome-inactivating proteins were found in high amounts in one line of cells of Phytolacca americana (pokeweed) cultured in vitro and, in less quantity, in lines of Saponaria officinalis (soapwort) and of Zea mays (corn) cells. 2. The main ribosome-inactivating protein from pokeweed cells was purified to homogeneity. It is a protein with Mr 29,000 and basic pI, similar to the ‘pokeweed antiviral protein’ (PAP), a ribosome-inactivating protein from pokeweed leaves. We propose to call the pokeweed antiviral protein isolated from pokeweed cells PAP-C. 3. PAP-C inactivates ribosomes in a less-than-equimolar ratio, thus inhibiting protein synthesis by a rabbit reticulocyte lysate with an IC50 (concentration causing 50% inhibition) of 0.067 nM (2 ng/ml), and modifies rRNA in a manner apparently identical to that of ricin and other ribosome-inactivating proteins. It inhibits protein synthesis by intact cells with an IC50 of 0.7-3.4 microM, and is toxic to mice with an LD50 of 0.95 mg/kg.

scholarly journals Purification and partial characterization of another form of the antiviral protein from the seeds of Phytolacca americana L. (pokeweed)

1982 ◽  
Vol 203 (1) ◽  
pp. 55-59 ◽  
Author(s):  
L Barbieri ◽  
G M Aron ◽  
J D Irvin ◽  
F Stirpe
Keyword(s):  
Protein Synthesis ◽  
High Yield ◽  
Phytolacca Americana ◽  
Pokeweed Antiviral Protein ◽  
Antiviral Protein ◽  
Whole Cells ◽  
Reticulocyte Lysate ◽  
Simplex Virus

1. The pokeweed antiviral protein, previously identified in two forms (PAP and PAP II) in the leaves of Phytolacca americana (pokeweed) [Obrig. Irvin & Hardesty (1973) Arch. Biochem. Biophys. 155, 278-289; Irvin, Kelly & Robertus (1980) Arch. Biochem. Biophys. 200, 418-425] is a protein that prevents replication of several viruses and inactivates ribosomes, thus inhibiting protein synthesis. 2. PAP is present in several forms in the seeds of pokeweed. One of them, which we propose to call ‘pokeweed antiviral protein from seeds’ (PAP-S) was purified in high yield (180 mg per 100 g of seeds) by chromatography on CM-cellulose, has mol.wt. 30 000, and is similar to, but not identical with. PAP and PAP II. 3. PAP-S inhibits protein synthesis in a rabbit reticulocyte lysate with an ID50 (concentration giving 50% inhibition) of 1.1 ng/ml (3.6 × 10(-11) M), but has much less effect on protein synthesis by whole cells, with an ID50 of 1 mg/ml (3.3 × 10(-5) M), and inhibits replication of herpes simplex virus type 1.

scholarly journals Seed extracts inhibiting protein synthesis in vitro

1980 ◽  
Vol 186 (2) ◽  
pp. 439-441 ◽  
Author(s):  
A Gasperi-Campani ◽  
L Barbieri ◽  
P Morelli ◽  
F Stirpe
Keyword(s):  
Protein Synthesis ◽  
Rabbit Reticulocyte Lysate ◽  
Intact Cells ◽  
Euonymus Europaeus ◽  
Lower Extent ◽  
Reticulocyte Lysate ◽  
Dialysis Membranes ◽  
Inhibiting Protein ◽  
Seed Extracts

Of 33 seed extracts examined, 12 inhibited protein synthesis in a rabbit reticulocyte lysate. This activity seems to be due to a protein, since (i) it was recovered with the (NH4)2SO4 precipitate, (ii) it was retained by dialysis membranes, and (iii) in all cases but one was destroyed by boiling. Only the extracts from the seeds of Adenia digitata and, to a lower extent, of Euonymus europaeus inhibited protein synthesis in intact cells.

scholarly journals Inhibition of protein synthesis in vitro by a lectin from Momordica charantia and by other haemagglutinins

1979 ◽  
Vol 182 (2) ◽  
pp. 633-635 ◽  
Author(s):  
L Barbieri ◽  
E Lorenzoni ◽  
F Stirpe
Keyword(s):  
Protein Synthesis ◽  
Ricinus Communis ◽  
Rutilus Rutilus ◽  
Momordica Charantia ◽  
Phytolacca Americana ◽  
Commercial Preparation ◽  
Reticulocyte Lysate ◽  
Vicia Cracca ◽  
Mitogenic Lectin

Protein synthesis by a rabbit reticulocyte lysate is inhibited by the haemagglutinating lectins from Momordica charantia and Crotalaria juncea seeds and from the roe of Rutilus rutilus, and by a commercial preparation of the mitogenic lectin from Phytolacca americana. The haemagglutinins from the seeds of Ricinus communis and of Vicia cracca acquired inhibitory activity after their reduction with 2-mercaptoethanol.

scholarly journals Some ribosome-inactivating proteins depurinate ribosomal RNA at multiple sites

1992 ◽  
Vol 286 (1) ◽  
pp. 1-4 ◽  
Author(s):  
L Barbieri ◽  
J M Ferreras ◽  
A Barraco ◽  
P Ricci ◽  
F Stirpe
Keyword(s):  
Rat Liver ◽  
Ribosomal Rna ◽  
House Fly ◽  
Phytolacca Americana ◽  
Antiviral Protein ◽  
Ribosome Inactivating Protein ◽  
Ribosome Inactivating Proteins ◽  
Plant Enzymes ◽  
Trichosanthes Kirilowii ◽  
Liver Ribosomes

Saporin-S6, a ribosome-inactivating protein (RIP) from Saponaria officinalis released more than 1 mol of adenine/mol of ribosomes from house fly (Musca domestica) larvae and from rat liver. The release of adenine from rat liver ribosomes by several RIPs (plant enzymes with RNA N-glycosidase activity) was examined. Saporins, pokeweed antiviral protein from roots of Phytolacca americana (PAP-R), and trichokirin from Trichosanthes kirilowii seeds depurinated rat liver ribosomes at more than one site. Up to 33 mol of adenine were released from 1 mol of ribosomes. This property is not common to all RIPS.

scholarly journals Generation of a mutant form of protein synthesis initiation factor eIF-2 lacking the site of phosphorylation by eIF-2 kinases.

1988 ◽  
Vol 8 (2) ◽  
pp. 993-995 ◽  
Author(s):  
V K Pathak ◽  
D Schindler ◽  
J W Hershey
Keyword(s):  
Protein Synthesis ◽  
Mammalian Cells ◽  
Covalent Modification ◽  
Site Directed Mutagenesis ◽  
Initiation Factor ◽  
Alpha Subunit ◽  
Mutant Form ◽  
Two Dimensional Gel Electrophoresis ◽  
Reticulocyte Lysate

The phosphorylation of the alpha-subunit of initiation factor eIF-2 leads to an inhibition of protein synthesis in mammalian cells. We have performed site-directed mutagenesis on a cDNA encoding the alpha-subunit of human eIF-2 and have replaced the candidate sites of phosphorylation, Ser-48 and Ser-51, with alanines. The cDNAs were expressed in vitro by SP6 polymerase transcription and rabbit reticulocyte lysate translation, and the radiolabeled protein products were analyzed by high-resolution two-dimensional gel electrophoresis. The wild-type and Ser-48 mutant proteins became extensively phosphorylated by eIF-2 kinases present in the reticulocyte lysate, and when additional heme-controlled repressor or double-stranded RNA-activated kinase was present, phosphorylation of the proteins was enhanced. The Ser-51 mutant showed little covalent modification by the endogenous enzymes and showed no increase in the acidic variant with additional eIF-2 kinases, thereby suggesting that Ser-51 is the site of phosphorylation leading to repression of protein synthesis.

TXU (Anti-CD7)-Pokeweed Antiviral Protein as a Potent Inhibitor of Human Immunodeficiency Virus

1998 ◽  
Vol 42 (2) ◽  
pp. 383-388 ◽  
Author(s):  
Fatih M. Uckun ◽  
Lisa M. Chelstrom ◽  
Lisa Tuel-Ahlgren ◽  
Ilker Dibirdik ◽  
James D. Irvin ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Scid Mouse ◽  
Pokeweed Antiviral Protein ◽  
Antiviral Protein ◽  
Cynomolgus Monkeys ◽  
Immunodeficiency Virus ◽  
Scid Mouse Model ◽  
Anti Hiv ◽  
Hiv 1

ABSTRACT We have evaluated the clinical potential of TXU (anti-CD7)-pokeweed antiviral protein (PAP) immunoconjugate (TXU-PAP) as a new biotherapeutic anti-human immunodeficiency virus (anti-HIV) agent by evaluating its anti-HIV type 1 (anti-HIV-1) activity in vitro, as well as in a surrogate human peripheral blood lymphocyte-severe combined immunodeficient (Hu-PBL-SCID) mouse model of human AIDS. The present report documents in a side-by-side comparison the superior in vitro anti-HIV-1 activity of TXU-PAP compared to the activities of zidovudine, 2′,3′-didehydro-2′,3′-dideoxythymidine, unconjugated PAP, and B53-PAP, an anti-CD4-PAP immunoconjugate. Notably, TXU-PAP elicited potent anti-HIV activity in the Hu-PBL-SCID mouse model of human AIDS without any side effects and at doses that were very well tolerated by cynomolgus monkeys. Furthermore, plasma samples from TXU-PAP-treated cynomolgus monkeys showed potent anti-HIV-1 activity in vitro.

scholarly journals Structure-Based Design and Engineering of a Nontoxic Recombinant Pokeweed Antiviral Protein with Potent Anti-Human Immunodeficiency Virus Activity

2003 ◽  
Vol 47 (3) ◽  
pp. 1052-1061 ◽  
Author(s):  
Fatih M. Uckun ◽  
Francis Rajamohan ◽  
Sharon Pendergrass ◽  
Zahide Ozer ◽  
Barbara Waurzyniak ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Scid Mouse ◽  
Pokeweed Antiviral Protein ◽  
Antiviral Protein ◽  
Immunodeficiency Virus ◽  
Scid Mouse Model ◽  
Anti Hiv ◽  
Hiv 1

ABSTRACT A molecular model of pokeweed antiviral protein (PAP)-RNA interactions was used to rationally engineer FLP-102(151AA152) and FLP-105(191AA192) as nontoxic PAPs with potent anti-human immunodeficiency virus (anti-HIV) activities. FLP-102 and FLP-105 have been produced in Escherichia coli and tested both in vitro and in vivo. These proteins depurinate HIV type 1 (HIV-1) RNA much better than rRNA and are more potent anti-HIV agents than native PAP or recombinant wild-type PAP. They are substantially less toxic than native PAP in BALB/c mice and exhibit potent in vivo activities against genotypically and phenotypically nucleoside reverse transcriptase inhibitor-resistant HIV-1 in a surrogate human peripheral blood lymphocyte (Hu-PBL) SCID mouse model of human AIDS. Rationally engineered nontoxic recombinant PAPs such as FLP-102 and FLP-105 may provide the basis for effective salvage therapies for patients harboring highly drug-resistant strains of HIV-1. The documented in vitro potencies of FLP-102 and FLP-105, their in vivo antiretroviral activities in the HIV-infected Hu-PBL SCID mouse model, and their favorable toxicity profiles in BALB/c mice warrant the further development of these promising new biotherapeutic agents.

scholarly journals A Neutralizing Antibody to the A Chain of Abrin Inhibits Abrin Toxicity both In Vitro and In Vivo

2008 ◽  
Vol 15 (5) ◽  
pp. 737-743 ◽  
Author(s):  
Kalpana Surendranath ◽  
Anjali A. Karande
Keyword(s):  
Monoclonal Antibody ◽  
Protein Synthesis ◽  
Neutralizing Antibody ◽  
Type Ii ◽  
Inhibit Protein Synthesis ◽  
Ribosome Inactivating Proteins ◽  
A Chain ◽  
Lethal Doses

ABSTRACT Plant ribosome-inactivating proteins (RIPs) are RNA N-glycosidases that inhibit protein synthesis in cells. Abrin, a type II RIP, is an AB type toxin, which is one of the most lethal types of toxin known. The B chain facilitates the entry of the molecule into the cell, whereas the A chain exerts the toxic effect. We have generated hybridomas secreting antibodies of the immunoglobulin G class specific to the recombinant A chain of abrin. One monoclonal antibody, namely, D6F10, rescued cells from abrin toxicity. Importantly, the antibody also protected mice from lethal doses of the toxin. The neutralizing effect of the antibody was shown to be due to interference with abrin attachment to the cell surface.

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