Applying kinetics and footprinting analysis, we show that telithromycin, a ketolide antibiotic, binds to Escherichia coli ribosomes in a two-step process. During the first, rapidly equilibrated step, telithromycin binds to a low-affinity site (K(T) = 500 nM), in which the lactone ring is positioned at the upper portion of the peptide exit tunnel, while the alkyl-aryl side chain of the drug inserts a groove formed by nucleotides A789 and U790 of 23S rRNA. During the second step, telithromycin shifts slowly to a high-affinity site (K(T)* = 8.33 nM), in which the lactone ring remains essentially at the same position, while the side chain interacts with the base pair U2609:A752 and the extended loop of protein L22. Consistently, mutations perturbing either the base pair U2609:A752 or the L22-loop hinder shifting of telithromycin to the final position, without affecting the initial step of binding. In contrast, mutation Lys63Glu in protein L4 placed on the opposite side of the tunnel, exerts only a minor effect on telithromycin binding. Polyamines disfavor both sequential steps of binding. Our data correlate well with recent crystallographic data and rationalize the changes in the accessibility of ribosomes to telithromycin in response to ribosomal mutations and ionic changes.
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http://dx.doi.org/10.1093/nar/gks174 | DOI Listing |
Cell Discov
July 2024
Key Laboratory of Medicinal Molecule Science and Pharmaceutical Engineering, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, China.
Conventional macrolide-lincosamide-streptogramin B-ketolide (MLSK) antibiotics are unable to counter the growing challenge of antibiotic resistance that is conferred by the constitutive methylation of rRNA base A2058 or its G2058 mutation, while the presence of unmodified A2058 is crucial for high selectivity of traditional MLSK in targeting pathogens over human cells. The absence of effective modes of action reinforces the prevailing belief that constitutively antibiotic-resistant Staphylococcus aureus remains impervious to existing macrolides including telithromycin. Here, we report the design and synthesis of a novel series of macrolides, featuring the strategic fusion of ketolide and quinolone moieties.
View Article and Find Full Text PDFJ Biomol Struct Dyn
September 2024
School of Biochemical Engineering, Indian Institute of Technology (BHU), Varanasi, India.
In the pursuit of developing novel anti-leishmanial agents, we conducted an extensive computational study to screen inhibitors from the FDA-approved ZINC database against glutathione synthetase. The three-dimensional structure of glutathione synthetase was constructed by homology modeling, using the crystallographic structure of glutathione synthetase as a template. Subsequently, molecular docking studies were carried out for a large number of compounds using AutoDock Vina.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
November 2021
Department of Theory, Max-Planck-Institut für Kohlenforschung, 45470 Mülheim an der Ruhr, Germany;
Antibiotic resistance is a major threat to global health; this problem can be addressed by the development of new antibacterial agents to keep pace with the evolutionary adaptation of pathogens. Computational approaches are essential tools to this end since their application enables fast and early strategical decisions in the drug development process. We present a rational design approach, in which acylide antibiotics were screened based on computational predictions of solubility, membrane permeability, and binding affinity toward the ribosome.
View Article and Find Full Text PDFNat Commun
July 2021
Institute for Biochemistry and Molecular Biology, University of Hamburg, Hamburg, Germany.
Macrolides and ketolides comprise a family of clinically important antibiotics that inhibit protein synthesis by binding within the exit tunnel of the bacterial ribosome. While these antibiotics are known to interrupt translation at specific sequence motifs, with ketolides predominantly stalling at Arg/Lys-X-Arg/Lys motifs and macrolides displaying a broader specificity, a structural basis for their context-specific action has been lacking. Here, we present structures of ribosomes arrested during the synthesis of an Arg-Leu-Arg sequence by the macrolide erythromycin (ERY) and the ketolide telithromycin (TEL).
View Article and Find Full Text PDFNat Commun
May 2021
Center for Biomolecular Sciences, University of Illinois at Chicago, Chicago, IL, USA.
Macrolide antibiotics bind in the nascent peptide exit tunnel of the bacterial ribosome and prevent polymerization of specific amino acid sequences, selectively inhibiting translation of a subset of proteins. Because preventing translation of individual proteins could be beneficial for the treatment of human diseases, we asked whether macrolides, if bound to the eukaryotic ribosome, would retain their context- and protein-specific action. By introducing a single mutation in rRNA, we rendered yeast Saccharomyces cerevisiae cells sensitive to macrolides.
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