8ekb

From Proteopedia

Crystal structure of the Thermus thermophilus 70S ribosome in complex with mRNA, deacylated P-site tRNAmet, and thermorubin at 2.70A resolution

Structural highlights

8ekb is a 20 chain structure with sequence from Thermus thermophilus HB8. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.7Å
Ligands:	, , , , , , , , , , , , , , , , , ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

RL2_THET8 One of the primary rRNA binding proteins. Required for association of the 30S and 50S subunits to form the 70S ribosome, for tRNA binding and peptide bond formation. It has been suggested to have peptidyltransferase activity; this is somewhat controversial (By similarity). Makes several contacts with the 16S rRNA (forming bridge B7b) in the 70S ribosome.[HAMAP-Rule:MF_01320_B]

Publication Abstract from PubMed

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.

Insights into the molecular mechanism of translation inhibition by the ribosome-targeting antibiotic thermorubin.,Paranjpe MN, Marina VI, Grachev AA, Maviza TP, Tolicheva OA, Paleskava A, Osterman IA, Sergiev PV, Konevega AL, Polikanov YS, Gagnon MG Nucleic Acids Res. 2023 Jan 11;51(1):449-462. doi: 10.1093/nar/gkac1189. PMID:36546783^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Paranjpe MN, Marina VI, Grachev AA, Maviza TP, Tolicheva OA, Paleskava A, Osterman IA, Sergiev PV, Konevega AL, Polikanov YS, Gagnon MG. Insights into the molecular mechanism of translation inhibition by the ribosome-targeting antibiotic thermorubin. Nucleic Acids Res. 2023 Jan 11;51(1):449-462. PMID:36546783 doi:10.1093/nar/gkac1189