scholarly journals Mechanism of Inhibition of Translation Termination by Blasticidin S

2018 ◽  
Vol 430 (5) ◽  
pp. 591-593 ◽  
Author(s):  
Egor Svidritskiy ◽  
Andrei A. Korostelev
2020 ◽  
Vol 477 (15) ◽  
pp. 2921-2934
Author(s):  
Rodrigo D. Requião ◽  
Géssica C. Barros ◽  
Tatiana Domitrovic ◽  
Fernando L. Palhano

Protein segments with a high concentration of positively charged amino acid residues are often used in reporter constructs designed to activate ribosomal mRNA/protein decay pathways, such as those involving nonstop mRNA decay (NSD), no-go mRNA decay (NGD) and the ribosome quality control (RQC) complex. It has been proposed that the electrostatic interaction of the positively charged nascent peptide with the negatively charged ribosomal exit tunnel leads to translation arrest. When stalled long enough, the translation process is terminated with the degradation of the transcript and an incomplete protein. Although early experiments made a strong argument for this mechanism, other features associated with positively charged reporters, such as codon bias and mRNA and protein structure, have emerged as potent inducers of ribosome stalling. We carefully reviewed the published data on the protein and mRNA expression of artificial constructs with diverse compositions as assessed in different organisms. We concluded that, although polybasic sequences generally lead to lower translation efficiency, it appears that an aggravating factor, such as a nonoptimal codon composition, is necessary to cause translation termination events.


2020 ◽  
Vol 16 (4) ◽  
pp. 531-543
Author(s):  
Shaheen Faizi ◽  
Tahira Sarfaraz ◽  
Saima Sumbul ◽  
Almas Jabeen ◽  
Sobia A. Halim ◽  
...  

Background: In continuation of our work on Mannich reaction on 8-hydroxyquinoline, fifteen different combinations of aromatic aldehydes and aniline were subjected to Mannich reaction from which twelve products (eight Mannich bases, two imines and two intramolecularly cyclized products with benzofuranone skeleton) were obtained. Among them six compounds (1, 2, 6, 8, 9 and 12) are the new compounds. The structures of the compounds were characterized by UV, IR, MS and 1H NMR. Method: The compounds were tested for the inhibition of pro-inflammatory cytokines tumor necrosis factor-α (TNF-α) and Interleukin-1β (IL-1β) at a concentration of 25 µg/mL. The cytokines were produced by THP-1 cells differentiated with PMA for 24hrs and stimulated with LPS for 4 hrs and supernatant were analyzed through ELISA technique. Results and Discussion: Compounds 1-5, 8 and 9 inhibited the production of TNF-α and IL-1β. Compounds 1, 3, and 8 exerted potent inhibitions of TNF-α with 71%, 71%, and 83% inhibition, respectively. Compounds 1 and 8 significantly inhibited the production of IL-1β with 64% and 78% inhibition, respectively. Conclusion: Compounds 1 and 8 significantly inhibited the production of IL-1β with 64% and 78% inhibition, respectively. Notably compound 8 showed the most potent inhibition of these cytokines. Additionally, the effect of compounds on viability of THP-1 cells was also evaluated. Moreover, molecular docking was carried out to study the mechanism of inhibition of TNF-α production.


1980 ◽  
Vol 45 (2) ◽  
pp. 641-652
Author(s):  
Petr Zbořil

Semiquinone is an intermediary product of the oxidation of daphnetin (7,8-dihydroxycoumarin) and esculetin (6,7-dihydroxycoumarin) by diphenol oxidase; its concentration rapidly decreases. When the oxidation is effected by ferricytochrome c, the concentration of the semiquinone remains practically constant for a long period. Similarly, the ability of the products of daphnetin oxidation by diphenol oxidase to inhibit succinate oxidase activity in mitochondrial fragments rapidly decreases with time; the decrease is considerably slower in the case of cytochrome c. The inhibitory activity of the product decreases with time also during esculetin oxidation by ferricyanide. This indicates that the inhibitory effects must be ascribed predominantly to the semiquinone, the quinone is less efficient. The inhibition of succinate oxidase or succinate dehydrogenase was strongly decreased when the enzyme preparation of Keilin and Hartree was incubated with esculetin and ferricyanide in the presence of KCN or under anaerobic conditions. This demonstrates that the reaction of the inhibitor with the enzyme either involves subsequent oxidations or that the inhibitor preferentially reacts with the oxidized form of the sensitive component of the respiratory chain. The second alternative is very little probable since there is no correlation between the degree of inhibition and the binding of the inhibitor to mitochondrial fragments.


1989 ◽  
Vol 37 (10) ◽  
pp. 2855-2857 ◽  
Author(s):  
Shigeharu NOCHI ◽  
Naoyuki SHIMOMURA ◽  
Teiichi HATTORI ◽  
Tadashi SATO ◽  
Yasuo MIYAKE ◽  
...  

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