L22 Ribosomal Protein and Effect of Its Mutation on Ribosome Resistance to Erythromycin

Davydova, Natalia; Streltsov, V.A.; Wilce, Matthew Charles James; Liljas, Anders; Garber, Maria

doi:10.1016/s0022-2836(02)00772-6

Cited by 48 publications

(45 citation statements)

References 32 publications

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“…These results explain the altered chemical reactivity in E. coli ⌬MKR ribosomes of 23S-RNA bases (13). Together, these results support a prevailing model in which the L22 ⌬MKR deletion confers antibiotic resistance by allowing nascent proteins to enter the ribosome exit tunnel despite bound macrolides (18,19).Here, we rule out the accepted model of L22-mediated macrolide resistance by showing that E. coli ⌬MKR ribosomes are inhibited by erythromycin in vitro and in vivo. Instead, the ⌬MKR mutation appears to reduce the intracellular concentration of macrolides.…”

supporting

confidence: 76%

supporting

confidence: 69%

“…Cryo-EM studies initially revealed a widened exit tunnel in E. coli ⌬MKR ribosomes (18). This loop is also displaced to create an expanded tunnel in structures of ⌬MKR ribosomes from Thermus thermophilus and Haloarcula marismortui (4,19). These results explain the altered chemical reactivity in E. coli ⌬MKR ribosomes of 23S-RNA bases (13).…”

mentioning

confidence: 99%

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Revisiting the mechanism of macrolide-antibiotic resistance mediated by ribosomal protein L22

Moore

Sauer²

2008

Proc. Natl. Acad. Sci. U.S.A.

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Bacterial antibiotic resistance can occur by many mechanisms. An intriguing class of mutants is resistant to macrolide antibiotics even though these drugs still bind to their targets. For example, a 3-residue deletion (⌬MKR) in ribosomal protein L22 distorts a loop that forms a constriction in the ribosome exit tunnel, apparently allowing nascent-chain egress and translation in the presence of bound macrolides. Here, however, we demonstrate that ⌬MKR and wild-type ribosomes show comparable macrolide sensitivity in vitro. In Escherichia coli, we find that this mutation reduces antibiotic occupancy of the target site on ribosomes in a manner largely dependent on the AcrAB-TolC efflux system. We propose a model for antibiotic resistance in which ⌬MKR ribosomes alter the translation of specific proteins, possibly via changes in programmed stalling, and modify the cell envelope in a manner that lowers steady-state macrolide levels.ermC ͉ erythromycin ͉ ribosome ͉ TolC M any antibiotics inhibit bacterial protein synthesis. Understanding how microbes become antibiotic resistant is important both for developing effective treatment regimens and designing new therapeutics. Macrolides consist of a 14-to 16-member lactone ring with different appended sugars and comprise a key group of inhibitors of bacterial translation (1, 2). The inhibitory activity of macrolides, including erythromycin, depends on binding to a site near the polypeptide exit tunnel of the large ribosomal subunit (3, 4). Because macrolides do not bind to ribosomes with an occupied exit tunnel and cause the synthesis of 2-10 residue peptides in translation assays in vitro, it has been proposed that drug binding physically blocks elongation of nascent proteins beyond this size (5-7).Some macrolide-resistance mutations alter the ribosomal target site and prevent binding (4,8). Intriguingly, other mutations confer resistance despite the fact that macrolides still bind the mutant ribosome well (8-10). For example, deletion of the M 82 K 83 R 84 sequence in Escherichia coli ribosomal protein L22 (⌬MKR) allows growth in the presence of high levels of erythromycin and other macrolides (11-13). The same mutation makes Haemophilus influenzae resistant to numerous macrolides (14); different L22 mutations also confer macrolide resistance in other bacterial species (2). When binding has been measured, ribosomes with macrolideresistant alterations in L22 bind erythromycin with near wild-type affinity (8,10,12,15).In a crystal structure of the E. coli ribosome, the MKR sequence is part of an extended L22 loop, which together with a similar loop in protein L4 forms a narrow constriction in the exit tunnel (Fig. 1A) (16, 17). Cryo-EM studies initially revealed a widened exit tunnel in E. coli ⌬MKR ribosomes (18). This loop is also displaced to create an expanded tunnel in structures of ⌬MKR ribosomes from Thermus thermophilus and Haloarcula marismortui (4, 19). These results explain the altered chemical reactivity in E. coli ⌬MKR ribosomes of 23S-RNA bases (13). Together,...

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supporting

confidence: 76%

supporting

confidence: 69%

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Revisiting the mechanism of macrolide-antibiotic resistance mediated by ribosomal protein L22

Moore

Sauer²

2008

Proc. Natl. Acad. Sci. U.S.A.

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“…Remarkably, this rather unusual elongated shape is also maintained in the isolated native 63 and mutated protein. 64 Furthermore, in all known L22 structures flexibility was observed only in the hairpin tip hinge region [Plate 3(a)]. The electrostatic properties of the surface of protein L22 support the suggestion for a common mechanism for tunnel blockage accomplished by swinging of L22 hairpin tip.…”

Section: Tunnel Discrimination Of Nascent Proteinsmentioning

confidence: 75%

Functional aspects of ribosomal architecture: symmetry, chirality and regulation

Zarivach

Bashan

Berisio

et al. 2004

J of Physical Organic Chem

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High-resolution structures of both ribosomal subunits revealed that most stages of protein biosynthesis, including decoding of genetic information, are navigated and controlled by the elaborate ribosomal architecturaldesign. Remote interactions govern accurate substrate alignment within a flexible active-site pocket [peptidyl transferase center (PTC)], and spatial considerations, due mainly to a universal mobile nucleotide, U2585, ensure proper chirality by interfering with D-amino-acids incorporation. tRNA translocation involves two correlated motions: overall mRNA/tRNA (messenger and transfer RNA) shift, and a rotation of the tRNA single-stranded aminoacylated-3 0 end around the bond connecting it with the tRNA helical-regions. This bond coincides with an axis passing through a sizable symmetry-related region, identified around the PTC in all large-subunit crystal structures. Propelled by a bulged universal nucleotide, A2602, positioned at the two-fold symmetry axis, and guided by a ribosomal-RNA scaffold along an exact pattern, the rotatory motion results in stereochemistry optimal for peptide-bond formation and in geometry ensuring nascent proteins entrance into their exit tunnel. Hence, confirming that ribosomes contribute positional rather than chemical catalysis, and that peptide bond formation is concurrent with A-to P-site tRNA passage. Connecting between the PTC, the decoding center, the tRNA entrance and exit points, the symmetry-related region can transfer intra-ribosomal signals between remote functional locations, guaranteeing smooth processivity of amino acids polymerization. Ribosomal proteins are involved in accurate substrate placement (L16), discrimination and signal transmission (L22) and protein biosynthesis regulation (CTC). Residing on the exit tunnel walls near its entrance, and stretching to its opening, protein-L22 can mediate ribosome response to cellular regulatory signals, since it can swing across the tunnel, causing gating and elongation arrest. Each of the protein CTC domains has a defined task. The N-terminal domain stabilizes the intersubunit-bridge confining the A-site-tRNA entrance. The middle domain protects the bridge conformation at elevated temperatures. The C-terminal domain can undergo substantial conformational rearrangements upon substrate binding, indicating CTC participation in biosynthesiscontrol under stressful conditions.

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“…Interestingly, mutations at L4 lead to large reductions in the binding affinity while the L22 mutants show no change in the binding constant but still confer resistance. This is explained by a widening of the tunnel, which allows passage of the peptide without affecting the binding 59. The second and most common resistance mechanism is modification of the rRNA.…”

Section: Protein Synthesis Inhibitorsmentioning

confidence: 99%

Targeting Antibiotic Resistance

2016

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Finding strategies against the development of antibiotic resistance is a major global challenge for the life sciences community and for public health. The past decades have seen a dramatic worldwide increase in human‐pathogenic bacteria that are resistant to one or multiple antibiotics. More and more infections caused by resistant microorganisms fail to respond to conventional treatment, and in some cases, even last‐resort antibiotics have lost their power. In addition, industry pipelines for the development of novel antibiotics have run dry over the past decades. A recent world health day by the World Health Organization titled “Combat drug resistance: no action today means no cure tomorrow” triggered an increase in research activity, and several promising strategies have been developed to restore treatment options against infections by resistant bacterial pathogens.

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L22 Ribosomal Protein and Effect of Its Mutation on Ribosome Resistance to Erythromycin

Cited by 48 publications

References 32 publications

Revisiting the mechanism of macrolide-antibiotic resistance mediated by ribosomal protein L22

Revisiting the mechanism of macrolide-antibiotic resistance mediated by ribosomal protein L22

Functional aspects of ribosomal architecture: symmetry, chirality and regulation

Targeting Antibiotic Resistance

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