Structure-Guided Discovery of Novel Aminoglycoside Mimetics as Antibacterial Translation Inhibitors

Zhou, Yang; Gregor, V.; Sun, Zhongxiang; Ayida, Benjamin K.; Winters, Geoffrey C.; Murphy, Douglas E.; Simonsen, Klaus B.; Vourloumis, Dionisios; Fish, Sarah; Froelich, Jamie M.; Wall, Daniel; Hermann, Thomas

doi:10.1128/aac.49.12.4942-4949.2005

Cited by 49 publications

(45 citation statements)

References 31 publications

(34 reference statements)

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“…The bactericidal activity of most clinically used antibiotics depends on cell metabolism, as they target essential cellular enzymes or processes. To gain insight whether TA kills in a targetspecific manner, we tested whether a bacteriostatic antibiotic (CM) could block TA's bactericidal activity (52). Polymyxin B, a bactericidal antibiotic that disrupts membrane integrity in a noncell-growth-dependent manner, was used as a control.…”

Section: Resultsmentioning

confidence: 99%

Myxobacterium-Produced Antibiotic TA (Myxovirescin) Inhibits Type II Signal Peptidase

Xiao

Gerth

Müller

et al. 2012

Antimicrob Agents Chemother

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Antibiotic TA is a macrocyclic secondary metabolite produced by myxobacteria that has broad-spectrum bactericidal activity. The structure of TA is unique, and its molecular target is unknown. Here, we sought to elucidate TA's mode of action (MOA) through two parallel genetic approaches. First, chromosomal Escherichia coli TA-resistant mutants were isolated. One mutant that showed specific resistance toward TA was mapped and resulted from an IS4 insertion in the lpp gene, which encodes an abundant outer membrane (Braun's) lipoprotein. In a second approach, the comprehensive E. coli ASKA plasmid library was screened for overexpressing clones that conferred TA r . This effort resulted in the isolation of the lspA gene, which encodes the type II signal peptidase that cleaves signal sequences from prolipoproteins. In whole cells, TA was shown to inhibit Lpp prolipoprotein processing, similar to the known LspA inhibitor globomycin. Based on genetic evidence and prior globomycin studies, a block in Lpp expression or prevention of Lpp covalent cell wall attachment confers TA r by alleviating a toxic buildup of mislocalized pro-Lpp. Taken together, these data argue that LspA is the molecular target of TA. Strikingly, the giant ta biosynthetic gene cluster encodes two lspA paralogs that we hypothesize play a role in producer strain resistance.

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Section: Resultsmentioning

confidence: 99%

Myxobacterium-Produced Antibiotic TA (Myxovirescin) Inhibits Type II Signal Peptidase

Xiao

Gerth

Müller

et al. 2012

Antimicrob Agents Chemother

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“…The utility of such an approach has been demonstrated by impressive progress in understanding the mechanism of binding and action of aminoglycosides, which interact with a defined segment of helix 44 of 16 S rRNA with a distinctive structure. The ability to chemically synthesize the aminoglycoside binding site in isolation and use it in structural and functional studies paved the way for development of new drug prototypes that act on this site (61)(62)(63)(64)(65)(66). With these considerations in mind, we identified five elements of 23 S rRNA (sites I-V; Fig.…”

Section: Discussionmentioning

confidence: 99%

Potential New Antibiotic Sites in the Ribosome Revealed by Deleterious Mutations in RNA of the Large Ribosomal Subunit

Yassin¹,

Mankin

2007

Journal of Biological Chemistry

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The ribosome is the main target for antibiotics that inhibit protein biosynthesis. Despite the chemical diversity of the known antibiotics that affect functions of the large ribosomal subunit, these drugs act on only a few sites corresponding to some of the known functional centers. We have used a genetic approach for identifying structurally and functionally critical sites in the ribosome that can be used as new antibiotic targets. By using randomly mutagenized rRNA genes, we mapped rRNA sites where nucleotide alterations impair the ribosome function or assembly and lead to a deleterious phenotype. A total of 77 single-point deleterious mutations were mapped in 23 S rRNA and ranked according to the severity of their deleterious phenotypes. Many of the mutations mapped to familiar functional sites that are targeted by known antibiotics. However, a number of mutations were located in previously unexplored regions. The distribution of the mutations in the spatial structure of the ribosome showed a strong bias, with the strongly deleterious mutations being mainly localized at the interface of the large subunit and the mild ones on the solvent side. Five sites where deleterious mutations tend to cluster within discrete rRNA elements were identified as potential new antibiotic targets. One of the sites, the conserved segment of helix 38, was studied in more detail. Although the ability of the mutant 50 S subunits to associate with 30 S subunits was impaired, the lethal effect of mutations in this rRNA element was unrelated to its function as an intersubunit bridge. Instead, mutations in this region had a profound deleterious effect on the ribosome assembly.

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“…The formation of novel hybrid aminoglycoside compounds between neomycin and hygromycin is an indication of the importance of these drugs in controlling infections (21,27). More studies such as this one are needed to elucidate the potential of ribosomal-subunit assembly as an antibiotic target and to increase our understanding of the mechanism behind specific inhibition of this vital cellular function.…”

Section: Discussionmentioning

confidence: 99%

Hygromycin B Inhibition of Protein Synthesis and Ribosome Biogenesis in Escherichia coli

McGaha

Champney

2007

Antimicrob Agents Chemother

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The aminoglycoside antibiotic hygromycin B was examined in Escherichia coli cells for inhibitory effects on translation and ribosomal-subunit formation. Pulse-chase labeling experiments were performed, which verified lower rates of ribosomal-subunit synthesis in drug-treated cells. Hygromycin B exhibited a concentrationdependent inhibitory effect on viable-cell numbers, growth rate, protein synthesis, and 30S and 50S subunit formation. Unlike other aminoglycosides, hygromycin B was a more effective inhibitor of translation than of ribosomal-subunit formation in E. coli. Examination of total RNA from treated cells showed an increase in RNA corresponding to a precursor to the 16S rRNA, while mature 16S rRNA decreased. Northern hybridization to rRNA in cells treated with hygromycin B showed that RNase II-and RNase III-deficient strains of E. coli accumulated 16S rRNA fragments upon treatment with the drug. The results indicate that hygromycin B targets protein synthesis and 30S ribosomal-subunit assembly.Currently, only a limited number of antibiotics are available to treat multidrug-resistant strains of infectious bacteria, and resistance to even the newest antimicrobial agents is appearing (13). Increasing antibiotic resistance in microbial populations has necessitated the search for alternate cellular targets for new and existing antimicrobial agents. There are many antibiotics available that inhibit translation in bacterial cells by binding to the 30S or 50S ribosomal subunit (3). It has been observed that a number of ribosomal antibiotics possess a second inhibitory activity that prevents ribosomal-subunit assembly. The formation of a functional ribosome is a vital cellular process and is therefore also an important cellular target (4).In order to broaden our understanding of subunit assembly inhibitors, it is important to examine new or poorly studied antibiotics for their possible effects on inhibition of subunit formation. Identifying and comparing these antimicrobial agents will aid in the search for more suitable targets for future antibiotics. Crystallographic data have been obtained for several antibiotics from the aminoglycoside class (2, 25). These studies have shown that binding occurs through unique base interactions in the decoding center of the 30S ribosome, which effectively halts translation by preventing movements necessary for protein synthesis to occur (8). Recent work with the aminoglycoside compounds neomycin and paromomycin has shown that these antimicrobial agents have a second inhibitory target, which is inhibition of 30S ribosomal-subunit formation (18,19). These drugs are capable of inhibiting 30S ribosomalsubunit formation by stalling assembly at an intermediate phase of 30S biosynthesis.There are many antibiotics that target translation by binding to ribosomal subunits that have not been examined for possible inhibitory effects on ribosomal-subunit assembly. One of those antimicrobial agents is the aminoglycoside hygromycin B, a 30S subunit translational inhibitor. Most aminoglycosid...

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Structure-Guided Discovery of Novel Aminoglycoside Mimetics as Antibacterial Translation Inhibitors

Cited by 49 publications

References 31 publications

Myxobacterium-Produced Antibiotic TA (Myxovirescin) Inhibits Type II Signal Peptidase

Myxobacterium-Produced Antibiotic TA (Myxovirescin) Inhibits Type II Signal Peptidase

Potential New Antibiotic Sites in the Ribosome Revealed by Deleterious Mutations in RNA of the Large Ribosomal Subunit

Hygromycin B Inhibition of Protein Synthesis and Ribosome Biogenesis in Escherichia coli

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