Eukaryotic 80S ribosome aminoacyl-tRNA site (A-site) in the peptidyl transferase center (80S ribosome A-site)

The eukaryotic 80S ribosome A-site in the peptidyl transferase center (PTC) is a fundamental component of the cellular machinery responsible for protein synthesis [1]. This site is located within the large (60S) ribosomal subunit and is the location where the 3' end of the aminoacyl-tRNA is positioned to undergo peptide bond formation with the growing polypeptide chain [3]. While historically viewed as a target for antibiotics in prokaryotes, the eukaryotic A-site is increasingly recognized as a therapeutic target for nonsense suppression therapy in genetic disorders [5]. Small molecules, such as certain aminoglycosides and their derivatives like ELX-02, bind to this region to induce translational read-through of premature stop codons, potentially restoring the production of full-length proteins in diseases like cystic fibrosis [2]. Furthermore, the PTC is a target for various ribotoxic stress-inducing agents and translation inhibitors used in oncology research. Selective targeting of the eukaryotic ribosome remains a challenge due to the potential for systemic toxicity and interference with mitochondrial protein synthesis [1]. Understanding the structural nuances of the eukaryotic A-site is essential for developing selective modulators that minimize toxicity while restoring the production of essential proteins.

Other names

Eukaryotic ribosomal A-site80S PTC A-siteAminoacyl-tRNA binding siteRibosomal decoding center (eukaryotic)

Drugs targeting this site typically modulate the fidelity of the decoding process or inhibit peptide bond formation. In nonsense suppression therapy, molecules bind the A-site to induce a conformational change that allows near-cognate tRNA to pair with a premature stop codon, facilitating the synthesis of full-length proteins [1, 2].