7u2i

Crystal structure of the Thermus thermophilus 70S ribosome in complex with mRNA, aminoacylated A-site Gly-NH-tRNAgly, aminoacylated P-site fMet-NH-tRNAmet, deacylated E-site tRNAgly, and chloramphenicol at 2.55A resolution

spinqualitylabelsall models 7u2i, resolution 2.55Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7u2i 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 2.55Å Ligands: 0TD, 2MA, 2MG, 31H, 4OC, 4SU, 5MC, 5MU, CLM, G7M, K, L3X, M2G, MA6, MG, OMC, OMG, OMU, PSU, UR3, ZN 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 Ribosome serves as a universal molecular machine capable of synthesis of all the proteins in a cell. Small-molecule inhibitors, such as ribosome-targeting antibiotics, can compromise the catalytic versatility of the ribosome in a context-dependent fashion, preventing transpeptidation only between particular combinations of substrates. Classic peptidyl transferase center inhibitor chloramphenicol (CHL) fails to inhibit transpeptidation reaction when the incoming A site acceptor substrate is glycine, and the molecular basis for this phenomenon is unknown. Here, we present a set of high-resolution X-ray crystal structures that explain why CHL is unable to inhibit peptide bond formation between the incoming glycyl-tRNA and a nascent peptide that otherwise is conducive to the drug action. Our structures reveal that fully accommodated glycine residue can co-exist in the A site with the ribosome-bound CHL. Moreover, binding of CHL to a ribosome complex carrying glycyl-tRNA does not affect the positions of the reacting substrates, leaving the peptide bond formation reaction unperturbed. These data exemplify how small-molecule inhibitors can reshape the A-site amino acid binding pocket rendering it permissive only for specific amino acid residues and rejective for the other substrates extending our detailed understanding of the modes of action of ribosomal antibiotics. Structural basis for the inability of chloramphenicol to inhibit peptide bond formation in the presence of A-site glycine.,Syroegin EA, Aleksandrova EV, Polikanov YS Nucleic Acids Res. 2022 Jul 22;50(13):7669-7679. doi: 10.1093/nar/gkac548. PMID:35766409 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ribosomal protein THX 3D structures Ribosome 3D structures

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