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Shedko ED, Goloveshkina EN, Akimkin VG. Molecular epidemiology and antimicrobials resistance mechanism of Mycoplasma genitlaium. VESTNIK DERMATOLOGII I VENEROLOGII 2021. [DOI: 10.25208/vdv1192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Currently, infections caused by Mycoplasma genitalium are ones the most common sexually transmitted infections. Their prevalence is varied from 1.3% to 15.9%. Infections caused by M.genitalium may lead to urethritis in men and a wide spectrum of diseases in women. Antibiotic resistance now is one of the most emerging problems both in the scientific and in the healthcare fields. The usage of antimicrobials inhibiting cell wall synthesis for the treatment of M.genitalium is ineffective, and resistance to macrolides and fluoroquinolones is increasing rapidly. M.genitalium infections diagnostics is complicated due to specific conditions and duration of culture methods. The usage of nucleic acid amplification techniques is the most relevant for laboratory diagnostics, and is used in existing assays. This review compiles current data on the prevalence, molecular mechanisms of pathogenesis and antibiotic resistance, as well as diagnostics methods of M.genitalium.
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Zhang L, He J, Bai L, Ruan S, Yang T, Luo Y. Ribosome-targeting antibacterial agents: Advances, challenges, and opportunities. Med Res Rev 2021; 41:1855-1889. [PMID: 33501747 DOI: 10.1002/med.21780] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/08/2020] [Accepted: 12/19/2020] [Indexed: 02/05/2023]
Abstract
Ribosomes, which synthesize proteins, are critical organelles for the survival and growth of bacteria. About 60% of approved antibiotics discovered so far combat pathogenic bacteria by targeting ribosomes. However, several issues, such as drug resistance and toxicity, have impeded the clinical use of ribosome-targeting antibiotics. Moreover, the complexity of the bacteria ribosome structure has retarded the discovery of new ribosome-targeting agents that are considered as the key to the drug-resistance and toxicity. To deal with these challenges, efforts such as medicinal chemistry optimization, combination treatment, and new drug delivery system have been developed. But not enough, the development of structural biology and new screening methods bring powerful tools, such as cryo-electron microscopy technology, advanced computer-aided drug design, and cell-free in vitro transcription/translation systems, for the discovery of novel ribosome-targeting antibiotics. Thus, in this paper, we overview the research on different aspects of bacterial ribosomes, especially focus on discussing the challenges in the discovery of ribosome-targeting antibacterial drugs and advances made to address issues such as drug-resistance and selectivity, which, we believe, provide perspectives for the discovery of novel antibiotics.
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Affiliation(s)
- Laiying Zhang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Jun He
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Lang Bai
- Center of Infectious Diseases, State Key Laboratory of Biotherapy, West China Hospital, West China Medical School, Sichuan University and Collaborative Innovation Center, Chengdu, Sichuan, China
| | - Shihua Ruan
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Tao Yang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, China.,Laboratory of Human Diseases and Immunotherapy, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, China.,Institute of Immunology and Inflammation, Frontiers Science Center for Disease-Related Molecular Network, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, China
| | - Youfu Luo
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, West China Medical School, Sichuan University, Chengdu, Sichuan, China
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Salehi N, Attaran B, Zare-Mirakabad F, Ghadiri B, Esmaeili M, Shakaram M, Tashakoripour M, Eshagh Hosseini M, Mohammadi M. The outward shift of clarithromycin binding to the ribosome in mutant Helicobacter pylori strains. Helicobacter 2020; 25:e12731. [PMID: 32794288 DOI: 10.1111/hel.12731] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/30/2020] [Accepted: 07/03/2020] [Indexed: 02/06/2023]
Abstract
OBJECTIVES Disruption of protein synthesis, by drug-mediated restriction of the ribosomal nascent peptide exit tunnel (NPET), may inhibit bacterial growth. Here, we have studied the secondary and tertiary structures of domain V of the 23S rRNA in the wild-type and mutant (resistant) H. pylori strains and their mechanisms of interaction with clarithromycin (CLA). METHODS H pylori strains, isolated from cultured gastric biopsies, underwent CLA susceptibility testing by E test, followed by PCR amplification and sequencing of domain V of 23S rRNA. The homology model of this domain in H pylori, in complex with L4 and L22 accessory proteins, was determined based on the E. coli ribosome 3D structure. The interactions between CLA and 23S rRNA complex were determined by molecular docking studies. RESULTS Of the 70 H pylori strains, isolated from 200 dyspeptic patients, 11 (16%) were CLA-resistant. DNA sequencing identified categories with no (A), A2142G (B), and A2143G (C) mutations. Docking studies of our homology model of 23S rRNA complex with CLA showed deviated positions for categories B and C, in reference to category A, with 12.19 Å and 7.92 Å RMSD values, respectively. In both mutant categories, CLA lost its interactions at positions 2142 and 2587 and gained two new bonds with the L4 accessory protein. CONCLUSION Our data suggest that, in mutant H pylori strains, once the nucleotides at positions 2142 and 2587 are detached from the drug, CLA interacts with and is peeled back by the L4 accessory protein, removing the drug-imposed spatial restriction of the NPET.
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Affiliation(s)
- Najmeh Salehi
- Department of Bioinformatics, Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Bahareh Attaran
- HPGC Research Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran.,Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Tehran, Iran
| | - Fatemeh Zare-Mirakabad
- Department of Mathematics and Computer Science, Amirkabir University of Technology, Tehran, Iran
| | - Bahareh Ghadiri
- HPGC Research Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Maryam Esmaeili
- HPGC Research Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Mohadeseh Shakaram
- HPGC Research Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Mohammad Tashakoripour
- Gastroenterology Department, Amiralam Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahmoud Eshagh Hosseini
- Gastroenterology Department, Amiralam Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Marjan Mohammadi
- HPGC Research Group, Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
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4
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Yao W, Xu G, Bai B, Wang H, Deng M, Zheng J, Li D, Deng X, Liu X, Lin Z, Chen Z, Li G, Deng Q, Yu Z. In vitro-induced erythromycin resistance facilitates cross-resistance to the novel fluoroketolide, solithromycin, in Staphylococcus aureus. FEMS Microbiol Lett 2019; 365:4992303. [PMID: 29733362 DOI: 10.1093/femsle/fny116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 05/02/2018] [Indexed: 12/31/2022] Open
Abstract
The aim of this study was to determine whether in vitro induced erythromycin resistance facilitates the cross-resistance to the novel fluoroketolide, solithromycin, in Staphylococcus aureus. Four strains of methicillin-susceptible S. aureus strains S2, S3, S5 and S7 were successfully induced to establish erythromycin-resistant strains by continuous in vitro culture with erythromycin. Mutations at drug binding sites were shown to increase the minimal inhibitory concentrations for ketolides, including telithromycin and the novel compound solithromycin, but did not increase for lincosamides, chloramphenicols or oxazolidinones. In S2-, S5- and S7-derived strains, L22 protein mutations occurred first, resulting in a low level of cross-resistance to ketolides (≤4 μg/mL). The L4 protein mutations were dependent on the L22 protein, resulting in high-level cross-resistance to ketolides (≥8 μg/mL). In S3-derived strains, high levels of cross-resistance occurred concurrently in the 23S rRNA domains II/V and the L22 protein. Hence, long-term exposure of erythromycin results in resistance to ketolides in S. aureus through drug binding site mutations. These results demonstrate that since erythromycin has been used clinically for a long time, it is necessary to carefully evaluate the rewards and risks when prescribing solithromycin for the treatment of infectious diseases.
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Affiliation(s)
- Weiming Yao
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Shenzhen Nanshan Hospital of Shenzhen University, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Quality Control Center of Hospital Infection Management of Shenzhen, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China
| | - Guangjian Xu
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Shenzhen Nanshan Hospital of Shenzhen University, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Quality Control Center of Hospital Infection Management of Shenzhen, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China
| | - Bing Bai
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Shenzhen Nanshan Hospital of Shenzhen University, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Quality Control Center of Hospital Infection Management of Shenzhen, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China
| | - Hongyan Wang
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Shenzhen Nanshan Hospital of Shenzhen University, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Quality Control Center of Hospital Infection Management of Shenzhen, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China
| | - Minggui Deng
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Shenzhen Nanshan Hospital of Shenzhen University, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Quality Control Center of Hospital Infection Management of Shenzhen, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China
| | - Jinxin Zheng
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Shenzhen Nanshan Hospital of Shenzhen University, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Quality Control Center of Hospital Infection Management of Shenzhen, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Science and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, No 130, Dongan road, Xuhui District, Shanghai 200032, China
| | - Duoyun Li
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Shenzhen Nanshan Hospital of Shenzhen University, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Quality Control Center of Hospital Infection Management of Shenzhen, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China
| | - Xiangbin Deng
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Shenzhen Nanshan Hospital of Shenzhen University, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Quality Control Center of Hospital Infection Management of Shenzhen, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China
| | - Xiaojun Liu
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Shenzhen Nanshan Hospital of Shenzhen University, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Quality Control Center of Hospital Infection Management of Shenzhen, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China
| | - Zhiwei Lin
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Shenzhen Nanshan Hospital of Shenzhen University, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Quality Control Center of Hospital Infection Management of Shenzhen, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Science and Institutes of Biomedical Sciences, Shanghai Medical College of Fudan University, No 130, Dongan road, Xuhui District, Shanghai 200032, China
| | - Zhong Chen
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Shenzhen Nanshan Hospital of Shenzhen University, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Quality Control Center of Hospital Infection Management of Shenzhen, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China
| | - Guiqiu Li
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Shenzhen Nanshan Hospital of Shenzhen University, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Quality Control Center of Hospital Infection Management of Shenzhen, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China
| | - Qiwen Deng
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Shenzhen Nanshan Hospital of Shenzhen University, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Quality Control Center of Hospital Infection Management of Shenzhen, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China
| | - Zhijian Yu
- Department of Infectious Diseases and Shenzhen Key Lab for Endogenous Infection, Shenzhen Nanshan Hospital of Shenzhen University, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China.,Quality Control Center of Hospital Infection Management of Shenzhen, No 89, Taoyuan Road, Nanshan District, Shenzhen 518052, China
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5
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Dinos GP. The macrolide antibiotic renaissance. Br J Pharmacol 2017; 174:2967-2983. [PMID: 28664582 DOI: 10.1111/bph.13936] [Citation(s) in RCA: 214] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 05/29/2017] [Accepted: 06/20/2017] [Indexed: 12/19/2022] Open
Abstract
Macrolides represent a large family of protein synthesis inhibitors of great clinical interest due to their applicability to human medicine. Macrolides are composed of a macrocyclic lactone of different ring sizes, to which one or more deoxy-sugar or amino sugar residues are attached. Macrolides act as antibiotics by binding to bacterial 50S ribosomal subunit and interfering with protein synthesis. The high affinity of macrolides for bacterial ribosomes, together with the highly conserved structure of ribosomes across virtually all of the bacterial species, is consistent with their broad-spectrum activity. Since the discovery of the progenitor macrolide, erythromycin, in 1950, many derivatives have been synthesised, leading to compounds with better bioavailability and acid stability and improved pharmacokinetics. These efforts led to the second generation of macrolides, including well-known members such as azithromycin and clarithromycin. Subsequently, in order to address increasing antibiotic resistance, a third generation of macrolides displaying improved activity against many macrolide resistant strains was developed. However, these improvements were accompanied with serious side effects, leading to disappointment and causing many researchers to stop working on macrolide derivatives, assuming that this procedure had reached the end. In contrast, a recent published breakthrough introduced a new chemical platform for synthesis and discovery of a wide range of diverse macrolide antibiotics. This chemical synthesis revolution, in combination with reduction in the side effects, namely, 'Ketek effects', has led to a macrolide renaissance, increasing the hope for novel and safe therapeutic agents to combat serious human infectious diseases.
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Affiliation(s)
- George P Dinos
- Department of Biochemistry, School of Medicine, University of Patras, Patras, Greece
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6
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Sorokina I, Mushegian A. Rotational restriction of nascent peptides as an essential element of co-translational protein folding: possible molecular players and structural consequences. Biol Direct 2017; 12:14. [PMID: 28569180 PMCID: PMC5452302 DOI: 10.1186/s13062-017-0186-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Accepted: 05/23/2017] [Indexed: 12/13/2022] Open
Abstract
Background A basic tenet of protein science is that all information about the spatial structure of proteins is present in their sequences. Nonetheless, many proteins fail to attain native structure upon experimental denaturation and refolding in vitro, raising the question of the specific role of cellular machinery in protein folding in vivo. Recently, we hypothesized that energy-dependent twisting of the protein backbone is an unappreciated essential factor guiding the protein folding process in vivo. Torque force may be applied by the ribosome co-translationally, and when accompanied by simultaneous restriction of the rotational mobility of the distal part of the growing chain, the resulting tension in the protein backbone would facilitate the formation of local secondary structure and direct the folding process. Results Our model of the early stages of protein folding in vivo postulates that the free motion of both terminal regions of the protein during its synthesis and maturation is restricted. The long-known but unexplained phenomenon of statistical overrepresentation of protein termini on the surfaces of the protein structures may be an indication of the backbone twist-based folding mechanism; sustained maintenance of a twist requires that both ends of the protein chain are anchored in space, and if the ends are released only after the majority of folding is complete, they are much more likely to remain on the surface of the molecule. We identified the molecular components that are likely to play a role in the twisting of the nascent protein chain and in the anchoring of its N-terminus. The twist may be induced at the C-terminus of the nascent polypeptide by the peptidyltransferase center of the ribosome. Several ribosome-associated proteins, including the trigger factor in bacteria and the nascent polypeptide-associated complex in archaea and eukaryotes, may restrict the rotational mobility of the N-proximal regions of the peptides. Conclusions Many experimental observations are consistent with the hypothesis of co-translational twisting of the protein backbone. Several molecular players in this hypothetical mechanism of protein folding can be suggested. In addition, the new view of protein folding in vivo opens the possibility of novel potential drug targets to combat human protein folding diseases. Reviewers This article was reviewed by Lakshminarayan Iyer and István Simon. Electronic supplementary material The online version of this article (doi:10.1186/s13062-017-0186-1) contains supplementary material, which is available to authorized users.
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7
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In vitro antibacterial activity of α-methoxyimino acylide derivatives against macrolide-resistant pathogens and mutation analysis in 23S rRNA. J Antibiot (Tokyo) 2017; 70:264-271. [DOI: 10.1038/ja.2016.148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Revised: 10/27/2016] [Accepted: 11/13/2016] [Indexed: 11/08/2022]
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8
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Auerbach-Nevo T, Baram D, Bashan A, Belousoff M, Breiner E, Davidovich C, Cimicata G, Eyal Z, Halfon Y, Krupkin M, Matzov D, Metz M, Rufayda M, Peretz M, Pick O, Pyetan E, Rozenberg H, Shalev-Benami M, Wekselman I, Zarivach R, Zimmerman E, Assis N, Bloch J, Israeli H, Kalaora R, Lim L, Sade-Falk O, Shapira T, Taha-Salaime L, Tang H, Yonath A. Ribosomal Antibiotics: Contemporary Challenges. Antibiotics (Basel) 2016; 5:antibiotics5030024. [PMID: 27367739 PMCID: PMC5039520 DOI: 10.3390/antibiotics5030024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 06/07/2016] [Accepted: 06/20/2016] [Indexed: 11/30/2022] Open
Abstract
Most ribosomal antibiotics obstruct distinct ribosomal functions. In selected cases, in addition to paralyzing vital ribosomal tasks, some ribosomal antibiotics are involved in cellular regulation. Owing to the global rapid increase in the appearance of multi-drug resistance in pathogenic bacterial strains, and to the extremely slow progress in developing new antibiotics worldwide, it seems that, in addition to the traditional attempts at improving current antibiotics and the intensive screening for additional natural compounds, this field should undergo substantial conceptual revision. Here, we highlight several contemporary issues, including challenging the common preference of broad-range antibiotics; the marginal attention to alterations in the microbiome population resulting from antibiotics usage, and the insufficient awareness of ecological and environmental aspects of antibiotics usage. We also highlight recent advances in the identification of species-specific structural motifs that may be exploited for the design and the creation of novel, environmental friendly, degradable, antibiotic types, with a better distinction between pathogens and useful bacterial species in the microbiome. Thus, these studies are leading towards the design of “pathogen-specific antibiotics,” in contrast to the current preference of broad range antibiotics, partially because it requires significant efforts in speeding up the discovery of the unique species motifs as well as the clinical pathogen identification.
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Affiliation(s)
- Tamar Auerbach-Nevo
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - David Baram
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Anat Bashan
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Matthew Belousoff
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Elinor Breiner
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Chen Davidovich
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Giuseppe Cimicata
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Zohar Eyal
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Yehuda Halfon
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Miri Krupkin
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Donna Matzov
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Markus Metz
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Mruwat Rufayda
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Moshe Peretz
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Ophir Pick
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Erez Pyetan
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Haim Rozenberg
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Moran Shalev-Benami
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Itai Wekselman
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Raz Zarivach
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Ella Zimmerman
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Nofar Assis
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Joel Bloch
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Hadar Israeli
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Rinat Kalaora
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Lisha Lim
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Ofir Sade-Falk
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Tal Shapira
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Leena Taha-Salaime
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Hua Tang
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
| | - Ada Yonath
- Department of Structural Biology, Weizmann Institute, Rehovot 76100, Israel.
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9
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Forbes L, Ebsworth-Mojica K, DiDone L, Li SG, Freundlich JS, Connell N, Dunman PM, Krysan DJ. A High Throughput Screening Assay for Anti-Mycobacterial Small Molecules Based on Adenylate Kinase Release as a Reporter of Cell Lysis. PLoS One 2015; 10:e0129234. [PMID: 26098625 PMCID: PMC4476654 DOI: 10.1371/journal.pone.0129234] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 05/06/2015] [Indexed: 02/02/2023] Open
Abstract
Mycobacterium tuberculosis (Mtb) is well-established to be one of the most important bacterial pathogens for which new antimicrobial therapies are needed. Herein, we describe the development of a high throughput screening assay for the identification of molecules that are bactericidal against Mycobacteria. The assay utilizes the release of the intracellular enzyme adenylate kinase into the culture medium as a reporter of mycobacterial cell death. We demonstrate that the assay is selective for mycobactericidal molecules and detects anti-mycobacterial activity at concentrations below the minimum inhibitory concentration of many molecules. Thus, the AK assay is more sensitive than traditional growth assays. We have validated the AK assay in the HTS setting using the Mtb surrogate organism M. smegmatis and libraries of FDA approved drugs as well as a commercially available Diversity set. The screen of the FDA-approved library demonstrated that the AK assay is able to identify the vast majority of drugs with known mycobactericidal activity. Importantly, our screen of the Diversity set revealed that the increased sensitivity of the AK assay increases the ability of M. smegmatis-based screens to detect molecules with relatively poor activity against M. smegmatis but good to excellent activity against Mtb.
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Affiliation(s)
- Lauren Forbes
- Department of Microbiology/Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York, 14642, United States of America
| | - Katherine Ebsworth-Mojica
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York, 14642, United States of America
| | - Louis DiDone
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York, 14642, United States of America
| | - Shao-Gang Li
- Department of Pharmacology, Rutgers University, Newark, New Jersey, 07103, United States of America
| | - Joel S. Freundlich
- Department of Pharmacology, Rutgers University, Newark, New Jersey, 07103, United States of America
- Department of Physiology, Rutgers University, Newark, New Jersey, 07103, United States of America
- Department of Medicine, Center for Emerging and Re-emerging Pathogens, Rutgers University, Newark, New Jersey, 07103, United States of America
| | - Nancy Connell
- Department of Physiology, Rutgers University, Newark, New Jersey, 07103, United States of America
- Department of Medicine, Center for Emerging and Re-emerging Pathogens, Rutgers University, Newark, New Jersey, 07103, United States of America
| | - Paul M. Dunman
- Department of Microbiology/Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York, 14642, United States of America
- * E-mail: (DJK); (PMD)
| | - Damian J. Krysan
- Department of Microbiology/Immunology, University of Rochester School of Medicine and Dentistry, Rochester, New York, 14642, United States of America
- Department of Pediatrics, University of Rochester School of Medicine and Dentistry, Rochester, New York, 14642, United States of America
- * E-mail: (DJK); (PMD)
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10
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Nonaka S, Matsuzaki K, Kazama T, Nishiyama H, Ida Y, Koyano S, Sonobe K, Okamura N, Saito R. Antimicrobial susceptibility and mechanisms of high-level macrolide resistance in clinical isolates of Moraxella nonliquefaciens. J Med Microbiol 2013; 63:242-247. [PMID: 24196134 DOI: 10.1099/jmm.0.061788-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We investigated antimicrobial susceptibility and the molecular mechanism involved in conferring high-level macrolide resistance in 47 clinical isolates of Moraxella nonliquefaciens from Japan. Antimicrobial susceptibility was determined using Etest and agar dilution methods. Thirty-two erythromycin-non-susceptible strains were evaluated for the possibility of clonal spreading, using PFGE. To analyse the mechanism related to macrolide resistance, mutations in the 23S rRNA gene and the ribosomal proteins, and the presence of methylase genes were investigated by PCR and sequencing. The efflux system was examined using appropriate inhibitors. Penicillin, ampicillin, amoxicillin, cefixime, levofloxacin and antimicrobials containing β-lactamase inhibitors showed strong activity against 47 M. nonliquefaciens isolates. Thirty-two (68.1 %) of the 47 isolates showed high-level MICs to macrolides (MIC ≥128 mg l(-1)) and shared the A2058T mutation in the 23S rRNA gene. The geometric mean MIC to macrolides of A2058T-mutated strains was significantly higher than that of WT strains (P<0.0001). Thirty-two isolates with high-level macrolide MICs clustered into 30 patterns on the basis of the PFGE dendrogram, indicating that the macrolide-resistant strains were not clonal. In contrast, no common mutations of the ribosomal proteins or methylase genes, or overproduction of the efflux system were observed in A2058T-mutated strains. Moreover, of the 47 M. nonliquefaciens strains, 43 (91.5 %) were bro-1 and 4 (8.5 %) were bro-2 positive. Our results suggest that most M. nonliquefaciens clinical isolates show high-level macrolide resistance conferred by the A2058T mutation in the 23S rRNA gene. This study represents the first characterization of M. nonliquefaciens.
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Affiliation(s)
- Shotaro Nonaka
- Department of Microbiology and Immunology, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kosuke Matsuzaki
- Department of Microbiology and Immunology, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tomoya Kazama
- Department of Microbiology and Immunology, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hiroyuki Nishiyama
- Clinical Laboratory Department, Surugadai Nihon University Hospital, Tokyo, Japan
| | - Yoko Ida
- Department of Clinical Laboratory, Kyorin University Hospital, Tokyo, Japan
| | - Saho Koyano
- Department of Infection Control and Prevention, The University of Tokyo Hospital, Tokyo, Japan
| | - Kazunari Sonobe
- Department of Clinical Laboratory, Nippon Medical School, Tokyo, Japan
| | - Noboru Okamura
- Department of Microbiology and Immunology, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Ryoichi Saito
- Department of Microbiology and Immunology, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo, Japan
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11
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Schitter G, Wrodnigg TM. Update on carbohydrate-containing antibacterial agents. Expert Opin Drug Discov 2013; 4:315-56. [PMID: 23489128 DOI: 10.1517/17460440902778725] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Since the first known use of antibiotics > 2,500 years ago, a research field with immense importance for the welfare of mankind has been developed. After a decrease in interest in this topic by the end of the 20th century the occurrence of (poly-)resistant strains of bacteria induced a revival of antibiotics research. Health systems have been seeking viable and reliable solutions to this dangerous and expansive threat. OBJECTIVE This review will focus on carbohydrate-containing antibiotics and will give an outline of recently published novel isolated, semisynthetic as well as synthetic structures, their mechanism of action, if known, and the strategies for the design of compounds with potential by improved antibacterial properties. METHODS The literature between 2000 and 2008 was screened with main focus on recent examples of novel structures and strategies for the lead finding of exclusively antibacterial agents. RESULTS/CONCLUSION With the explanation of the role of the carbohydrate moieties in the respective antibacterial agents together with better synthetic strategies in carbohydrate chemistry as well as improvements in assay development for high throughput screening methods, carbohydrate-containing antibiotics can be used for the finding of potential drug leads that contribute to the fight against infections and diseases caused by (resistant) bacterial pathogens.
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Affiliation(s)
- Georg Schitter
- Technical University Graz, Institute of Organic Chemistry, Univ.-Doz. TMW, Dip.-Ing. GS, Glycogroup, A-8010 Graz, Austria +43 316 873 8744 ; +43 316 873 8740 ;
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Ruan ZX, Huangfu DS, Xu XJ, Sun PH, Chen WM. 3D-QSAR and molecular docking for the discovery of ketolide derivatives. Expert Opin Drug Discov 2013; 8:427-44. [DOI: 10.1517/17460441.2013.774369] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Zhi-Xiong Ruan
- Jinan University, College of Pharmacy, Department of Medicinal Chemistry,
Guangzhou 510632, P. R. China ;
| | - De-Sheng Huangfu
- Jinan University, College of Pharmacy, Department of Medicinal Chemistry,
Guangzhou 510632, P. R. China ;
| | - Xing-Jun Xu
- Jinan University, College of Pharmacy, Department of Medicinal Chemistry,
Guangzhou 510632, P. R. China ;
| | - Ping-Hua Sun
- Jinan University, College of Pharmacy, Department of Medicinal Chemistry,
Guangzhou 510632, P. R. China ;
| | - Wei-Min Chen
- Jinan University, College of Pharmacy, Department of Medicinal Chemistry,
Guangzhou 510632, P. R. China ;
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Fu LQ, Ling CY, Guo XS, He HL, Yang YS. Synthesis and antibacterial activity of pleuromutilin derivatives with novel C(14) side chain. CHINESE CHEM LETT 2012. [DOI: 10.1016/j.cclet.2011.10.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
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14
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Binding and action of CEM-101, a new fluoroketolide antibiotic that inhibits protein synthesis. Antimicrob Agents Chemother 2010; 54:4961-70. [PMID: 20855725 DOI: 10.1128/aac.00860-10] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We characterized the mechanism of action and the drug-binding site of a novel ketolide, CEM-101, which belongs to the latest class of macrolide antibiotics. CEM-101 shows high affinity for the ribosomes of Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. The ketolide shows high selectivity in its inhibitory action and readily interferes with synthesis of a reporter protein in the bacterial but not eukaryotic cell-free translation system. Binding of CEM-101 to its ribosomal target site was characterized biochemically and by X-ray crystallography. The X-ray structure of CEM-101 in complex with the E. coli ribosome shows that the drug binds in the major macrolide site in the upper part of the ribosomal exit tunnel. The lactone ring of the drug forms hydrophobic interactions with the walls of the tunnel, the desosamine sugar projects toward the peptidyl transferase center and interacts with the A2058/A2509 cleft, and the extended alkyl-aryl arm of the drug is oriented down the tunnel and makes contact with a base pair formed by A752 and U2609 of the 23S rRNA. The position of the CEM-101 alkyl-aryl extended arm differs from that reported for the side chain of the ketolide telithromycin complexed with either bacterial (Deinococcus radiodurans) or archaeal (Haloarcula marismortui) large ribosomal subunits but closely matches the position of the side chain of telithromycin complexed to the E. coli ribosome. A difference in the chemical structure of the side chain of CEM-101 in comparison with the side chain of telithromycin and the presence of the fluorine atom at position 2 of the lactone ring likely account for the superior activity of CEM-101. The results of chemical probing suggest that the orientation of the CEM-101 extended side chain observed in the E. coli ribosome closely resembles its placement in Staphylococcus aureus ribosomes and thus likely accurately reflects interaction of CEM-101 with the ribosomes of the pathogenic bacterial targets of the drug. Chemical probing further demonstrated weak binding of CEM-101, but not of erythromycin, to the ribosome dimethylated at A2058 by the action of Erm methyltransferase.
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Yonath A. Winterschlafende Bären, Antibiotika und die Evolution des Ribosoms (Nobel-Aufsatz). Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201001297] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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16
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Yonath A. Hibernating Bears, Antibiotics, and the Evolving Ribosome (Nobel Lecture). Angew Chem Int Ed Engl 2010; 49:4341-54. [DOI: 10.1002/anie.201001297] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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17
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Yonath A. Large facilities and the evolving ribosome, the cellular machine for genetic-code translation. J R Soc Interface 2009; 6 Suppl 5:S575-85. [PMID: 19656820 DOI: 10.1098/rsif.2009.0167.focus] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Well-focused X-ray beams, generated by advanced synchrotron radiation facilities, yielded high-resolution diffraction data from crystals of ribosomes, the cellular nano-machines that translate the genetic code into proteins. These structures revealed the decoding mechanism, localized the mRNA path and the positions of the tRNA molecules in the ribosome and illuminated the interactions of the ribosome with initiation, release and recycling factors. They also showed that the ribosome is a ribozyme whose active site is situated within a universal symmetrical region that is embedded in the otherwise asymmetric ribosome structure. As this highly conserved region provides the machinery required for peptide bond formation and for ribosome polymerase activity, it may be the remnant of the proto-ribosome, a dimeric pre-biotic machine that formed peptide bonds and non-coded polypeptide chains. Synchrotron radiation also enabled the determination of structures of complexes of ribosomes with antibiotics targeting them, which revealed the principles allowing for their clinical use, revealed resistance mechanisms and showed the bases for discriminating pathogens from hosts, hence providing valuable structural information for antibiotics improvement.
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Affiliation(s)
- Ada Yonath
- Department of Structural Biology, Weizmann Institute, 76100 Rehovot, Israel.
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Wekselman I, Davidovich C, Agmon I, Zimmerman E, Rozenberg H, Bashan A, Berisio R, Yonath A. Ribosome's mode of function: myths, facts and recent results. J Pept Sci 2009; 15:122-30. [DOI: 10.1002/psc.1077] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Fulle S, Gohlke H. Statics of the ribosomal exit tunnel: implications for cotranslational peptide folding, elongation regulation, and antibiotics binding. J Mol Biol 2009; 387:502-17. [PMID: 19356596 DOI: 10.1016/j.jmb.2009.01.037] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2008] [Revised: 01/18/2009] [Accepted: 01/21/2009] [Indexed: 10/21/2022]
Abstract
A sophisticated interplay between the static properties of the ribosomal exit tunnel and its functional role in cotranslational processes is revealed by constraint counting on topological network representations of large ribosomal subunits from four different organisms. As for the global flexibility characteristics of the subunit, the results demonstrate a conserved stable structural environment of the tunnel. The findings render unlikely that deformations of the tunnel move peptides down the tunnel in an active manner. Furthermore, the stable environment rules out that the tunnel can adapt widely so as to allow tertiary folding of nascent chains. Nevertheless, there are local zones of flexible nucleotides within the tunnel, between the peptidyl transferase center and the tunnel constriction, and at the tunnel exit. These flexible zones strikingly agree with previously identified folding zones. As for cotranslational elongation regulation, flexible residues in the beta-hairpin of the ribosomal L22 protein were verified, as suggested previously based on structural results. These results support the hypothesis that L22 can undergo conformational changes that regulate the tunnel voyage of nascent polypeptides. Furthermore, rRNA elements, for which conformational changes have been observed upon interaction of the tunnel wall with a nascent SecM peptide, are less strongly coupled to the subunit core. Sequences of coupled rigid clusters are identified between the tunnel and some of these elements, suggesting signal transmission by a domino-like mechanical coupling. Finally, differences in the flexibility of the glycosidic bonds of bases that form antibiotics-binding crevices within the peptidyl transferase center and the tunnel region are revealed for ribosomal structures from different kingdoms. In order to explain antibiotics selectivity, action, and resistance, according to these results, differences in the degrees of freedom of the binding regions may need to be considered.
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Affiliation(s)
- Simone Fulle
- Department of Biological Sciences, Molecular Bioinformatics Group, Goethe University, Frankfurt, Germany
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20
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Ribosome: an Ancient Cellular Nano-Machine for Genetic Code Translation. NATO SCIENCE FOR PEACE AND SECURITY SERIES B: PHYSICS AND BIOPHYSICS 2009. [DOI: 10.1007/978-90-481-2368-1_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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21
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Petropoulos AD, Kouvela EC, Starosta AL, Wilson DN, Dinos GP, Kalpaxis DL. Time-resolved binding of azithromycin to Escherichia coli ribosomes. J Mol Biol 2008; 385:1179-92. [PMID: 19071138 DOI: 10.1016/j.jmb.2008.11.042] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2008] [Revised: 11/13/2008] [Accepted: 11/18/2008] [Indexed: 11/19/2022]
Abstract
Azithromycin is a semisynthetic derivative of erythromycin that inhibits bacterial protein synthesis by binding within the peptide exit tunnel of the 50S ribosomal subunit. Nevertheless, there is still debate over what localization is primarily responsible for azithromycin binding and as to how many molecules of the drug actually bind per ribosome. In the present study, kinetic methods and footprinting analysis are coupled together to provide time-resolved details of the azithromycin binding process. It is shown that azithromycin binds to Escherichia coli ribosomes in a two-step process: The first-step involves recognition of azithromycin by the ribosomal machinery and places the drug in a low-affinity site located in the upper part of the exit tunnel. The second step corresponds to the slow formation of a final complex that is both much tighter and more potent in hindering the progression of the nascent peptide through the exit tunnel. Substitution of uracil by cytosine at nucleoside 2609 of 23S rRNA, a base implicated in the high-affinity site, facilitates the shift of azithromycin to this site. In contrast, mutation U754A hardly affects the binding process. Binding of azithromycin to both sites is hindered by high concentrations of Mg(2+) ions. Unlike Mg(2+) ions, polyamines do not significantly affect drug binding to the low-affinity site but attenuate the formation of the final complex. The low- and high-affinity sites of azithromycin binding are mutually exclusive, which means that one molecule of the drug binds per E. coli ribosome at a time. In contrast, kinetic and binding data indicate that in Deinococcus radiodurans, two molecules of azithromycin bind cooperatively to the ribosome. This finding confirms previous crystallographic results and supports the notion that species-specific structural differences may primarily account for the apparent discrepancies between the antibiotic binding modes obtained for different organisms.
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Van Bambeke F, Harms JM, Van Laethem Y, Tulkens PM. Ketolides: pharmacological profile and rational positioning in the treatment of respiratory tract infections. Expert Opin Pharmacother 2008; 9:267-83. [DOI: 10.1517/14656566.9.2.267] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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23
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Petropoulos AD, Kouvela EC, Dinos GP, Kalpaxis DL. Stepwise binding of tylosin and erythromycin to Escherichia coli ribosomes, characterized by kinetic and footprinting analysis. J Biol Chem 2007; 283:4756-65. [PMID: 18079110 DOI: 10.1074/jbc.m708371200] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Erythromycin and tylosin are 14- and 16-membered lactone ring macrolides, respectively. The current work shows by means of kinetic and chemical footprinting analysis that both antibiotics bind to Escherichia coli ribosomes in a two-step process. The first step established rapidly, involves a low-affinity binding site placed at the entrance of the exit tunnel in the large ribosomal subunit, where macrolides bind primarily through their hydrophobic portions. Subsequently, slow conformational changes mediated by the antibiotic hydrophilic portion push the drugs deeper into the tunnel, in a high-affinity site. Compared with erythromycin, tylosin shifts to the high-affinity site more rapidly, due to the interaction of the mycinose sugar of the drug with the loop of H35 in domain II of 23 S rRNA. Consistently, mutations of nucleosides U2609 and U754 implicated in the high-affinity site reduce the shift of tylosin to this site and destabilize, respectively, the final drug-ribosome complex. The weak interaction between tylosin and the ribosome is Mg2+ independent, unlike the tight binding. In contrast, both interactions between erythromycin and the ribosome are reduced by increasing concentrations of Mg2+ ions. Polyamines attenuate erythromycin affinity for the ribosome at both sequential steps of binding. In contrast, polyamines facilitate the initial binding of tylosin, but exert a detrimental, more pronounced, effect on the drug accommodation at its final position. Our results emphasize the role of the particular interactions that side chains of tylosin and erythromycin establish with 23 S rRNA, which govern the exact binding process of each drug and its response to the ionic environment.
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Binet R, Maurelli AT. Frequency of development and associated physiological cost of azithromycin resistance in Chlamydia psittaci 6BC and C. trachomatis L2. Antimicrob Agents Chemother 2007; 51:4267-75. [PMID: 17908942 PMCID: PMC2167982 DOI: 10.1128/aac.00962-07] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Azithromycin is a major drug used in the treatment and prophylaxis of chlamydial infections. Spontaneous azithromycin-resistant mutants of Chlamydia psittaci 6BC were isolated in vitro in the plaque assay at a frequency of about 10(-8). Isogenic clonal variants with A(2058)C, A(2059)G, or A(2059)C mutations in the unique 23S rRNA gene (Escherichia coli numbering system) displayed MICs for multiple macrolides (i.e., azithromycin, erythromycin, josamycin, and spiramycin) at least 100 times higher than those of the parent strain and were also more resistant to the lincosamide clindamycin. Chlamydia trachomatis L2 variants with a Gln-to-Lys substitution in ribosomal protein L4 at position 66 (E. coli numbering system), conferring an eightfold decrease in azithromycin and erythromycin sensitivities and a fourfold decrease in josamycin and spiramycin sensitivities, were isolated following serial passage in subinhibitory concentrations of azithromycin. Each mutation was stably maintained in the absence of selection but severely affected chlamydial infectivity, as determined by monitoring the development of each isolate over 46 h in the absence of selection, in pure culture or in 1:1 competition with the isogenic parent. Data in this study support the hypothesis that the mechanisms which confer high-level macrolide resistance in chlamydiae carry a prohibitive physiological cost and may thus limit the emergence of highly resistant clones of these important pathogens in vivo.
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Affiliation(s)
- Rachel Binet
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814-4799, USA
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