Aminoglycoside antibiotics and eukaryotic protein synthesis: stimulation of errors in the translation of natural messengers in extracts of cultured human cells

Inhibition of protein synthesis by aminoglycoside???arginine conjugates

“…Inhibitors of protein synthesis belong to an extremely important class of therapeutic drugs targeting bacterial ribosomes that are used in human and veterinary medicine+ Additionally, protein synthesis inhibitors have been useful tools to help assign ribosome functional domains and identify key steps of the translation process+ Aminoglycosides are not very effective at inhibiting eukaryotic cytoplasmic ribosomes (Fig+ 1A,B; 140 mM neomycin is required to achieve 60% inhibition of wheat germ ribosomes; Wilhelm et al+, 1978aWilhelm et al+, , 1978b)+ Arginine is also not a very good inhibitor of eukaryotic translation (50% inhibition at 20 mM; Palacian & Vazquez, 1979)+ However, the conjugation of aminoglycosides with arginine appears to generate a series of peptidomimetic compounds that show good activity in inhibiting eukaryotic translation (this study)+ Given the structural differences between the AACs and the parental compounds from which they are derived, we had no reason to suspect that AACs should have this property+ To our surprise, several of the AACs proved to be low micromolar inhibitors of eukaryotic translation (Fig+ 2)-a feature not associated with the original parental building blocks+…”

“…RNA contains complex and sophisticated higher order structures that are essential for recognition by other macromolecules and/or required for catalytic processes+ As such, it offers an interesting target for small molecule ligands and, indeed, the ability of RNA to interact with small molecules has long been recognized+ Antibiotics are a chemically and structurally diverse collection of molecules, with some classes capable of interacting with rRNA to exert profound effects on the translation process+ Functional insights from structural studies of compounds bound to ribosomal subunits have revealed that rRNA/small molecule ligand recognition is based on a combination of shape recognition, electrostatic, and hydrogen-bonding interactions Pioletti et al+, 2001;Schlunzen et al+, 2001)+ Additionally, RNA SELEX (Systematic Evolution of Ligands by Exponential Enrichment) has enabled the identification of minimal nucleic acid recognition motifs for ligand binding, demonstrating that RNA three-dimensional structures can form a large number of highly specific ligand-binding sites (Gold et al+, 1995)+ The ribosome is the target for many important antibacterial agents; these compounds interfere with essential steps of protein synthesis (Pestka, 1977;Gale et al+, 1981;Noller, 1991)+ Among these, 2-deoxystreptamine aminoglycosides (small polycationic compounds possessing linked ring systems consisting of aminosugars and an aminocyclitol) cause codon misreading by interfering with the decoding process + These compounds have found clinical use as antibacterial agents due to their ability to specifically bind bacterial ribosomes (Gale et al+, 1981) and are thought to exert their effects by increasing the error rate of the ribosome + Eukary-otic cytoplasmic ribosomes are relatively insensitive to 2-deoxystreptamine aminoglycosides (Kurtz, 1974;Palmer & Wilhelm, 1978;Wilhelm et al+, 1978aWilhelm et al+, , 1978b, and it has been suggested that the sensitivity of a ribosomal system to antibiotics is determined by the sequence of its rRNA (Sor & Fukuhara, 1984;Beckers et al+, 1995)+ Indeed, the nephrotoxicity and ototoxicity associated with use of aminoglycosides in the clinical setting may be linked to the susceptibility of mitochondrial ribosomes to these compounds (Bottger et al+, 2001)+ Aminoglycosides are also capable of binding to and affecting the activity of a large number of other RNAs, including the HIV TAR element (Mei et al+, 1997), HIV Rev-responsive element (Zapp et al+, 1993), hammerhead ribozymes (Stage et al+, 1995;Jenne et al+, 2001), hairpin ribozymes (Earnshaw & Gait, 1998), ribonuclease P RNA …”

Correction of genetic disease by making sense from nonsense

“…Commentary misreading in in vitro translation assays (18). Therefore, compounds such as paromomycin may be effective at lower doses and may display less toxicity than compounds such as gentamicin.…”

Aminoglycosides Affect IntracellularSalmonella entericaSerovars Typhimurium and Virchow

“…Other evidence suggested that aminoglycosides are able to penetrate the eukaryotic host cells and can even bind to the A site of the eukaryotic ribosome, promoting mistranslation (4,12,41). Aminoglycosides are thought to penetrate the eukaryotic cell through pinocytosis and to reach the phagosomes by fusion of the endosomes with the phagosomes (10).…”