Chemical Modifications of Momordin-a and Luffin-a, Ribosome-Inactivating Proteins from the Seeds ofMomordica charantiaandLuffa cylindrica: Involvement of His140, Tyr165, and Lys231 in the Protein-Synthesis Inhibitory Activity

1998 ◽  
Vol 62 (5) ◽  
pp. 959-964 ◽  
Author(s):  
Yuji MINAMI ◽  
M. Rafiqul ISLAM ◽  
Gunki FUNATSU
Keyword(s):  
Protein Synthesis ◽  
Inhibitory Activity ◽  
Chemical Modifications ◽  
Ribosome Inactivating Proteins

Ribosome-inactivating proteins (RIPs) and their important health promoting property

RSC Advances ◽  
2016 ◽  
Vol 6 (52) ◽  
pp. 46794-46805 ◽  
Author(s):  
Shuzhen Wang ◽  
Zhiliang Li ◽  
Shiming Li ◽  
Rong Di ◽  
Chi-Tang Ho ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Large Subunit ◽  
Ribosomal Rnas ◽  
Inhibit Protein Synthesis ◽  
Ribosome Inactivating Proteins ◽  
Important Health ◽  
Health Promoting

Ribosome-inactivating proteins (RIPs), widely present in plants, certain fungi and bacteria, can inhibit protein synthesis by removing one or more specific adenine residues from the large subunit of ribosomal RNAs (rRNAs).

Fungal ribotoxins: a family of naturally engineered targeted toxins?

1995 ◽  
Vol 73 (11-12) ◽  
pp. 1151-1159 ◽  
Author(s):  
Richard Kao ◽  
Julian Davies
Keyword(s):  
Protein Synthesis ◽  
Ribosomal Subunits ◽  
Site Specific ◽  
Phosphodiester Bond ◽  
Ribosome Inactivating Proteins ◽  
Diagnostic Agents ◽  
Molecular Studies ◽  
Related Proteins ◽  
Targeted Toxins

α-Sarcin, mitogillin, and restrictocin are small (~17 kDa) basic ribosome-inactivating proteins (RIPs) produced by the Aspergilli that catalytically inactivate the large ribosomal subunits of all organisms tested to date. These three fungal ribotoxins act as specific ribonucleases by hydrolyzing one single phosphodiester bond in the universally conserved α-sarcin domain of 23–28S rRNAs and are among the most potent inhibitors of protein synthesis known. Previous molecular studies of ribotoxins indicated that they belong to the superfamily of ribonucleases and analysis of the mitogillin gene employing PCR-mediated site-specific mutagenesis suggests that certain domains in ribotoxins, which share homologies with motifs in ribosome-related proteins, may be responsible for the targeting of ribotoxins to the ribosome. The applications of the ribotoxins as tools in research and their uses as therapeutic and diagnostic agents are also reviewed in this paper.Key words: ribotoxins, mitogillin, α-sarcin loop, protein synthesis, aspergillosis, immunotoxins.

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.

A Series of Extremely Potent Thrombin-Inhibitors Newly Synthetized

1975 ◽  
Author(s):  
S. Okamoto ◽  
A. Hijikata ◽  
R. Kikumoto ◽  
S. Tonomura ◽  
Y. Tamao
Keyword(s):  
Inhibitory Activity ◽  
High Selectivity ◽  
Animal Experiments ◽  
Chemical Compounds ◽  
Basic Structure ◽  
Thrombin Inhibitors ◽  
Chemical Modifications ◽  
Thrombin Activity ◽  
Low Toxicity ◽  
Very High

Starting with the simple arginine derivatives having weak thrombin-inhibitory activity, ca. 320 chemical compounds were designed and synthetized by the authors, in such a way as increasing the inhibitory activity by stepwise chemical modifications. The extremely potent inhibitors thus obtained are described.These inhibitors are chemcially naphthalene-sulfonyl-arginine derivatives, the basic structure being composed of three functional sub-units and designed, to reflect the part of fibrinogen peptide to be split by thrombin.One of the representatives, dansyl-arginine-ethyl-piperidine amide, inhibited 50% of thrombin activity at 0.1 μM when 5 μM fibrinogen was substrate. Similar result was also obtained when benzoyl-Phe-Val-Arg-pNA was substrate. The mode of inhibition was found competitive.The inhibitors suppressed the platelets aggregation due to thrombin satisfactorily. However, the inhibition on plasmin, reptilase or trypsin was far weaker, indicating the very high selectivity to thrombin. Their relatively low toxicity led the authors to extend the studies toward the animal experiments and results obtained will be reported elsewhere.

scholarly journals Levels of sdRNAs in cytoplasm and their association with ribosomes are dependent upon stress conditions but independent from snoRNA expression

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Anna M. Mleczko ◽  
Piotr Machtel ◽  
Mateusz Walkowiak ◽  
Anna Wasilewska ◽  
Piotr J. Pietras ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Protein Synthesis ◽  
Small Rna ◽  
Inhibitory Activity ◽  
Small Rnas ◽  
Stress Conditions ◽  
Dependent Manner ◽  
Rna Molecules ◽  
Stress Dependent ◽  
Ribosome Association

AbstractIn recent years, a number of small RNA molecules derived from snoRNAs have been observed. Findings concerning the functions of snoRNA-derived small RNAs (sdRNAs) in cells are limited primarily to their involvement in microRNA pathways. However, similar molecules have been observed in Saccharomyces cerevisiae, which is an organism lacking miRNA machinery. Here we examined the subcellular localization of sdRNAs in yeast. Our findings reveal that both sdRNAs and their precursors, snoRNAs, are present in the cytoplasm at levels dependent upon stress conditions. Moreover, both sdRNAs and snoRNAs may interact with translating ribosomes in a stress-dependent manner. Likely consequential to their ribosome association and protein synthesis suppression features, yeast sdRNAs may exert inhibitory activity on translation. Observed levels of sdRNAs and snoRNAs in the cytoplasm and their apparent presence in the ribosomal fractions suggest independent regulation of these molecules by yet unknown factors.

scholarly journals New ribosome-inactivating proteins and other proteins with protein synthesis–inhibiting activities

2020 ◽  
Vol 104 (10) ◽  
pp. 4211-4226 ◽  
Author(s):  
Jack Ho Wong ◽  
Hui Bao ◽  
Tzi Bun Ng ◽  
Helen Hei Ling Chan ◽  
Charlene Cheuk Wing Ng ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Ribosome Inactivating Proteins

scholarly journals Ribosome-inactivating proteins from the seeds of Saponaria officinalis L. (soapwort), of Agrostemma githago L. (corn cockle) and of Asparagus officinalis L. (asparagus), and from the latex of Hura crepitans L. (sandbox tree)

1983 ◽  
Vol 216 (3) ◽  
pp. 617-625 ◽  
Author(s):  
F Stirpe ◽  
A Gasperi-Campani ◽  
L Barbieri ◽  
A Falasca ◽  
A Abbondanza ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Sugar Content ◽  
Asparagus Officinalis ◽  
Inhibit Protein Synthesis ◽  
Nicotiana Glutinosa ◽  
Ribosome Inactivating Proteins ◽  
Local Lesions ◽  
Hura Crepitans ◽  
Reticulocyte Lysate ◽  
Saponaria Officinalis

Ribosome-inactivating proteins, similar to those already known [Barbieri & Stirpe (1982) Cancer Surveys 1, 489-520] were purified from the seeds of Saponaria officinalis (two proteins), of Agrostemma githago (three proteins), and of Asparagus officinalis (three proteins), and from the latex of Hura crepitans (one protein). The yield ranged from 8 to 400 mg/100 g of starting material. All proteins have an Mr of approx. 30000 and an alkaline isoelectric point. Their sugar content varies from 0 (proteins from S. officinalis) to 40% (protein from H. crepitans). The ribosome-inactivating proteins inhibit protein synthesis by rabbit reticulocyte lysate, the ID50 (concentration giving 50% inhibition) ranging from 1 ng/ml (a protein from S. officinalis) to 18 ng/ml (a protein from A. githago). Those which were tested (the proteins from S. officinalis and from A. githago) also inhibit polymerization of phenylalanine by isolated ribosomes, acting in an apparently catalytic manner. The protein from H. crepitans inhibited protein synthesis by HeLa cells, with an ID50 of 4 micrograms/ml, whereas the proteins from S. officinalis and from A. githago had an ID50 of more than 50-100 micrograms/ml. The ribosome-inactivating proteins from S. officinalis and from A. githago reduced the number of local lesions by tobacco-mosaic virus in the leaves of Nicotiana glutinosa.

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.

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