Eukaryotic 80S ribosome aminoacyl-tRNA binding site (A-site) (80S A-site)

The eukaryotic 80S ribosome A-site (aminoacyl-tRNA binding site) is a fundamental functional region within the protein-synthesizing machinery of eukaryotic cells, comprising components of both the 40S small subunit and the 60S large subunit [2, 5]. It serves as the entry point for aminoacyl-tRNA molecules, where the anticodon of the tRNA is matched against the mRNA codon in the decoding center of the 40S subunit, while the acceptor stem extends into the peptidyl transferase center (PTC) of the 60S subunit [4, 6]. This site is a major target for therapeutic intervention in oncology and genetic medicine [5]. In cancer, inhibitors like homoharringtonine (omacetaxine mepesuccinate) bind to the A-site of the PTC to prevent the correct positioning of aminoacyl-tRNAs, thereby halting translation elongation and inducing apoptosis in rapidly dividing cells [4, 5]. In the context of genetic diseases, specialized molecules such as ELX-02 (NB124) target the A-site decoding center to promote the read-through of premature stop codons, enabling the synthesis of full-length, functional proteins from genes containing nonsense mutations [1, 9]. A critical challenge in drug development for this target is achieving high selectivity for the eukaryotic cytosolic ribosome over the structurally similar bacterial and mitochondrial ribosomes to minimize toxicities like ototoxicity and nephrotoxicity [8, 9].

Other names

Aminoacyl-tRNA binding siteRibosomal A-siteEukaryotic decoding center80S aminoacyl siteA-site of the 80S ribosome

Inhibition of translation elongation by blocking aminoacyl-tRNA binding or induction of translational read-through of premature stop codons by altering decoding fidelity.