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Antibiotics: The Need for Innovation
Published in Nathan Keighley, Miraculous Medicines and the Chemistry of Drug Design, 2020
There is a wide diversity of antibiotics designed to target bacterial protein synthesis. Tetracycline antibiotics are a broad spectrum class of antibiotics that also bind to the 30S subunit, but have a different mode of action. They prevent aminoacyl tRNA from binding and stop growth of the protein. Other antibiotics target the 50S subunit of ribosomes, such as chloramphenicol, and work by inhibiting the movement of ribosomes along the mRNA strand. Chloramphenicol is the drug of choice for treating typhoid in some parts of the world, where more expensive drugs cannot be afforded.
Biochemical Aspects of Fatty Liver
Published in Robert G. Meeks, Steadman D. Harrison, Richard J. Bull, Hepatotoxicology, 2020
The system for protein synthesis may become damaged at different levels: at that of DNA transcription, or at that of the synthesis of mRNA, or at that of the function of ribosomes. Moreover, this can be affected at several sites, as aminoacyl-tRNA fixation, translation, and initiation.
Translation and Post-Translational Modifications During Aging
Published in Alvaro Macieira-Coelho, Molecular Basis of Aging, 2017
The function of a tRNA in transferring the amino acid to the ribosome-mRNA complex is dependent upon a specific enzyme that catalyzes the ligation of the appropriate amino acid to its acceptor arm at the 3′ end. This process, aminoacylation of a tRNA, is also known as “charging”, and the enzymes involved in this process are called aminoacyl-tRNA synthetases (aaRS) or, more accurately, aminoacyl-tRNA ligases. A group of isoaccepting tRNAs are charged only by the single aaRS specific for their amino acid.69
Surface atomic arrangement of nanomaterials affects nanotoxicity
Published in Nanotoxicology, 2021
Kaiwen Li, Zhongwei Wang, Hui Zeng, Jing Sun, Yue Wang, Qixing Zhou, Xiangang Hu
Metabolomics analysis provides a global view of the biological response to external stimuli (Krivitsky et al. 2019; Grintzalis et al. 2019). Branched chain amino acids (BCAAs) such as valine, leucine, isoleucine and threonine play a crucial role in skeletal muscle, affecting muscle morphology and function in living organisms (Wang et al. 2016). The main function of the aminoacyl-tRNAs is in protein synthesis (Raina and Ibba 2014). Compared to 1 T-MoS2, 2H-MoS2 upregulated BCAAs biosynthesis and aminoacyl-tRNA biosynthesis, indicating a stress response (Figure 6). Arginine is a nutritionally essential amino acid for embryonic survival and maintenance of vascular tone (Wu et al. 2009), and downregulated by both 1 T-MoS2 and 2H-MoS2. Compared to 1 T-MoS2, 2H-MoS2 downregulated glyoxylate and dicarboxylate metabolism, where glyoxylate and dicarboxylate metabolism are energy metabolism processes (Germain et al. 2017), explaining the higher toxicity of 2H-MoS2.
Translational readthrough inducing drugs for the treatment of inherited retinal dystrophies
Published in Expert Review of Ophthalmology, 2020
Christopher M Way, Dulce Lima Cunha, Mariya Moosajee
Nonsense mutations are single in-frame nucleotide changes that result in the formation of a stop codon – UAG, UAA, or UGA – termed a premature termination codon (PTC). PTCs can also be introduced by indel frameshift mutations and splice-site variants causing defective intron removal from pre-mRNA [13,16] or via aberrant alternative splicing of mRNA [17,18]; however, these are usually out-of-frame and not amenable to nonsense suppression. During normal translation, the aminoacyl-tRNA complex binds the ribosomal A-site, the amino acid is added to the peptide chain and translation continues (Figure 1(a)). If a PTC-containing mRNA transcript enters the ribosomal A-site, translation is prematurely terminated [19]. The mRNA then meets one of the two fates. Either, it is translated into a truncated protein, which is often nonfunctional or can harm the cell in a number of ways including misfolding, aggregation, or binding to cellular machinery and disrupting its structure or function, or rarely causing pathological gain of function (Figure 1(b)) [20,21]. Or, PTC-containing mRNA transcripts are degraded by a natural cellular surveillance mechanism called nonsense-mediated decay (NMD) [22] (Figure 2).
Utility of boron in dermatology
Published in Journal of Dermatological Treatment, 2020
David G. Jackson, Leah A. Cardwell, Elias Oussedik, Steven R. Feldman
Aminoacyl-tRNA synthetases facilitate protein synthesis by catalyzing the attachment of the proper amino acid to the tRNA. Certain aminoacyl-tRNA synthetases, such as leucyl-tRNA synthetase, have editing sites which provide proofreading capability and assurance of correct amino acid attachment. Tavaborole, a boron-based therapy for onychomycosis inhibits the fungal leucyl tRNA-synthetase thereby preventing synthesis of leucyl-tRNA and proteins (20). The boron atom in the oxaborole ring of tavaborole is vital to this mechanism of leucyl-tRNA synthetase inhibition. Tavaborole forms an adduct with leucyl-tRNA in the editing site of the leucyl tRNA synthetase enzyme, occupying the amino acid binding pocket in the editing site. The trapping of this adduct in the editing site of leucyl-tRNA synthetase facilitates inhibition of the enzyme (Figure 3).