Biology subjects

Grachev, A. A.

Publications and source records attributed to Grachev, A. A..

2 recordsLinked to original sources

bioRxiv2025

Insights into the bottromycin A2 mechanism of action

The spread of antimicrobial resistance among pathogenic bacteria poses a threat for modern medicine, highlighting the need for the discovery and development of new potential therapeutic agents. Bottromycin A2 (BotA2) represents a promising candidate for future drug development, exhibiting activity against clinically relevant methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and mycoplasma. However, its exact mechanism of action has not been fully elucidated until now. Here, we demonstrate that BotA2 inhibits bacterial translation showing unique context specificity with regard to the mRNA coding sequence. By using high-throughput toe-printing combined with deep sequencing (toe-seq analysis), we show that BotA2 induces ribosome stalling predominantly when a glycine codon enters the A-site of the ribosome, with stalling efficiency independent of codons located in the P- and E-sites. Our biochemical and biophysical data reveal that BotA2 arrests glycine-containing ternary complexes on the ribosome thereby preventing the full accommodation of incoming Gly-tRNAGly in the peptidyl transferase center. Altogether, our findings uncover a completely novel, previously undescribed mechanism of translation inhibition based on the context-specific immobilization of ternary complexes on elongating ribosomes. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=63 SRC="FIGDIR/small/671025v3_ufig1.gif" ALT="Figure 1"> View larger version (17K): org.highwire.dtl.DTLVardef@16ef44forg.highwire.dtl.DTLVardef@16984d0org.highwire.dtl.DTLVardef@8e7469org.highwire.dtl.DTLVardef@7cb57a_HPS_FORMAT_FIGEXP M_FIG GRAPHICAL ABSTRACT C_FIG

molecular biology↗

bioRxiv2022

Insights into the molecular mechanism of translation inhibition by the ribosome-targeting antibiotic thermorubin.

Thermorubin (THR) is an aromatic anthracenopyranone antibiotic active against both Gram-positive and Gram-negative bacteria. It is known to bind to the 70S ribosome at the intersubunit bridge B2a and was thought to inhibit factor-dependent initiation of translation and obstruct the accommodation of tRNAs into the A site. Here, we show that thermorubin causes ribosomes to stall in vivo and in vitro at internal and termination codons, thereby allowing the ribosome to initiate protein synthesis and translate at least a few codons before stalling. Our biochemical data show that THR affects multiple steps of translation elongation with a significant impact on the binding stability of the tRNA in the A site, explaining premature cessation of translation. Our high-resolution crystal and cryo-EM structures of the 70S-THR complex show that THR can co-exist with P- and A-site tRNAs, explaining how ribosomes can elongate in the presence of the drug. Remarkable is the ability of THR to arrest ribosomes at the stop codons. Our data suggest that by causing structural re-arrangements in the decoding center, THR interferes with the accommodation of tRNAs or release factors into the ribosomal A site. HIGHLIGHTSO_LIThermorubin is a potent inhibitor of protein synthesis both in vivo and in vitro; C_LIO_LIThermorubin does not prevent the binding of P- and A-site tRNAs; C_LIO_LIThermorubin affects multiple steps of translation elongation with a major impact on binding stability of the A-site tRNA; C_LIO_LIThermorubin can act as an inhibitor of translation termination on some ORFs. C_LI

molecular biology↗