Abstract
Deciphering translation is of paramount importance for the understanding of many diseases, and antibiotics played a pivotal role in this endeavour. Blasticidin S (BlaS) targets translation by binding to the peptidyl transferase center of the large ribosomal subunit. Using biochemical, structural and cellular approaches, we show here that BlaS inhibits both translation elongation and termination in Mammalia. Bound to mammalian terminating ribosomes, BlaS distorts the 3′CCA tail of the P-site tRNA to a larger extent than previously reported for bacterial ribosomes, thus delaying both, peptide bond formation and peptidyl-tRNA hydrolysis. While BlaS does not inhibit stop codon recognition by the eukaryotic release factor 1 (eRF1), it interferes with eRF1’s accommodation into the peptidyl transferase center and subsequent peptide release. In human cells, BlaS inhibits nonsense-mediated mRNA decay and, at subinhibitory concentrations, modulates translation dynamics at premature termination codons leading to enhanced protein production.
Highlights
Ribosome-targeting antibiotics are priceless tools in biochemistry and structural biology to dissect individual steps of translation and probe the modes of action of these antibiotics as well as of the factors involved in translation.A plethora of such compounds target translation initiation and elongation, and many of the antibiotics compromising elongation have been implemented in clinical practice [1]
We identified three 3D classes with ribosome bound to Blasticidin S (BlaS) with (i) an empty A-site (EmptyA), (ii) eukaryotic release factor 1 (eRF1) bound A-site and (iii) adopting hybrid P/E and A/P tRNA state (Hybrid) comprising 103,842, 18,397 and 29,879 particles respectively (Supplementary Figure S2)
Similar to the situation in bacteria, we found that BlaS slows down peptide release mediated by eRF1, eRF3a and GTP and partially prevents peptidyl-tRNA hydrolysis
Summary
Ribosome-targeting antibiotics are priceless tools in biochemistry and structural biology to dissect individual steps of translation and probe the modes of action of these antibiotics as well as of the factors involved in translation.A plethora of such compounds target translation initiation and elongation, and many of the antibiotics compromising elongation have been implemented in clinical practice [1]. Only very few antibiotics interfere with translation termination [1,2]. Blasticidin S (BlaS) is an inhibitor of translation termination in bacteria [3]. As early as in the 1960s, BlaS was known to inhibit protein synthesis in all kingdoms of life [3,4,5,6,7]. Structures show that BlaS binds to the P-site loop formed by ribosomal RNA within the peptidyl transferase center in the large ribosomal subunit of Thermus thermophilus [3], the archaea Haloarcula marismorui [8] and Saccharomyces cerevisiae [9]. Other antibiotics known to interfere with peptide bond formation, such as puromycin or anisomycin, bind to the Asite in the peptidyl transferase center and inhibit aminoacyltRNA binding in archaea and yeast [8,9]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
