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Li R, Shen X, Li Z, Shen J, Tang H, Xu H, Shen J, Xu Y. Combination of AS101 and Mefloquine Inhibits Carbapenem-Resistant Pseudomonas aeruginosa in vitro and in vivo. Infect Drug Resist 2023; 16:7271-7288. [PMID: 38023412 PMCID: PMC10664714 DOI: 10.2147/idr.s427232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/27/2023] [Indexed: 12/01/2023] Open
Abstract
Background In recent years, carbapenem-resistant Pseudomonas aeruginosa (CRPA) has spread around the world, leading to a high mortality and close attention of medical community. In this study, we aim to find a new strategy of treatment for CRPA infections. Methods Eight strains of CRPA were collected, and PCR detected the multi-locus sequence typing (MLST). The antimicrobial susceptibility test was conducted using the VITEK@2 compact system. The minimum inhibitory concentration (MIC) for AS101 and mefloquine was determined using the broth dilution method. Antibacterial activity was tested in vitro and in vivo through the chessboard assay, time killing assay, and a mouse model. The mechanism of AS101 combined with mefloquine against CRPA was assessed through the biofilm formation inhibition assay, electron microscopy, and detection of reactive oxygen species (ROS). Results The results demonstrated that all tested CRPA strains exhibited multidrug resistance. Moreover, our investigation revealed a substantial synergistic antibacterial effect of AS101-mefloquine in vitro. The assay for inhibiting biofilm formation indicated that AS101-mefloquine effectively suppressed the biofilm formation of CRPA-5 and CRPA-6. Furthermore, AS101-mefloquine were observed to disrupt the bacterial cell wall and enhance the permeability of the cell membrane. This effect was achieved by stimulating the production of ROS, which in turn hindered the growth of CRPA-3. To evaluate the therapeutic potential, a murine model of CRPA-3 peritoneal infection was established. Notably, AS101-mefloquine administration resulted in a significant reduction in bacterial load within the liver, kidney, and spleen of mice after 72 hours of treatment. Conclusion The present study showed that the combination of AS101 and mefloquine yielded a notable synergistic bacteriostatic effect both in vitro and in vivo, suggesting a potential clinical application of this combination in the treatment of CRPA.
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Affiliation(s)
- Rongrong Li
- Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, People’s Republic of China
- Provincial Laboratories of Pathogen Biology and Zoonoses, Anhui Medical University, Hefei, People’s Republic of China
| | - Xuhang Shen
- Department of Gastroenterology, The First Affiliated Hospital of Anhui Medical University, Hefei, People’s Republic of China
| | - Zhengyuan Li
- Orthopedics, The First Affiliated Hospital of Anhui Medical University, Hefei, People’s Republic of China
| | - Jilong Shen
- Provincial Laboratories of Pathogen Biology and Zoonoses, Anhui Medical University, Hefei, People’s Republic of China
| | - Hao Tang
- Department of Clinical Laboratory, the Second Affiliated Hospital of Anhui Medical University, Hefei, People’s Republic of China
| | - Huaming Xu
- Department of Clinical Laboratory, the First Affiliated Hospital of Anhui University of Traditional Chinese Medicine, Hefei, People’s Republic of China
| | - Jilu Shen
- Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, People’s Republic of China
- Anhui Public Health Clinical Center, Hefei, People’s Republic of China
| | - Yuanhong Xu
- Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, People’s Republic of China
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Privalsky TM, Soohoo AM, Wang J, Walsh CT, Wright GD, Gordon EM, Gray NS, Khosla C. Prospects for Antibacterial Discovery and Development. J Am Chem Soc 2021; 143:21127-21142. [PMID: 34860516 PMCID: PMC8855840 DOI: 10.1021/jacs.1c10200] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The rising prevalence of multidrug-resistant bacteria is an urgent health crisis that can only be countered through renewed investment in the discovery and development of antibiotics. There is no panacea for the antibacterial resistance crisis; instead, a multifaceted approach is called for. In this Perspective we make the case that, in the face of evolving clinical needs and enabling technologies, numerous validated antibacterial targets and associated lead molecules deserve a second look. At the same time, many worthy targets lack good leads despite harboring druggable active sites. Creative and inspired techniques buoy discovery efforts; while soil screening efforts frequently lead to antibiotic rediscovery, researchers have found success searching for new antibiotic leads by studying underexplored ecological niches or by leveraging the abundance of available data from genome mining efforts. The judicious use of "polypharmacology" (i.e., the ability of a drug to alter the activities of multiple targets) can also provide new opportunities, as can the continued search for inhibitors of resistance enzymes with the capacity to breathe new life into old antibiotics. We conclude by highlighting available pharmacoeconomic models for antibacterial discovery and development while making the case for new ones.
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Affiliation(s)
- Thomas M. Privalsky
- Department of Chemistry, Stanford University, Stanford, CA 94305, United States
| | - Alexander M. Soohoo
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, United States
| | - Jinhua Wang
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, MA 02215, United States,Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115 United States
| | - Christopher T. Walsh
- Department of Chemistry, Stanford University, Stanford, CA 94305, United States,Stanford ChEM-H, Stanford University, Stanford, CA 94305, United States
| | - Gerard D. Wright
- M.G. DeGroote Institute for Infectious Disease Research, Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8N 3Z5, Canada
| | - Eric M. Gordon
- Stanford ChEM-H, Stanford University, Stanford, CA 94305, United States,Department of Medicine, Stanford University, Stanford, CA 94305, United States
| | - Nathanael S. Gray
- Stanford ChEM-H, Stanford University, Stanford, CA 94305, United States,Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, United States
| | - Chaitan Khosla
- Department of Chemistry, Stanford University, Stanford, CA 94305, United States,Department of Chemical Engineering, Stanford University, Stanford, CA 94305, United States,Stanford ChEM-H, Stanford University, Stanford, CA 94305, United States,Corresponding Author: Correspondence to
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3
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Antibacterial apple cider vinegar eradicates methicillin resistant Staphylococcus aureus and resistant Escherichia coli. Sci Rep 2021; 11:1854. [PMID: 33473148 PMCID: PMC7817673 DOI: 10.1038/s41598-020-78407-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Accepted: 11/06/2020] [Indexed: 01/06/2023] Open
Abstract
Methicillin-resistant Staphylococcus aureus (MRSA) and resistant Escherichia coli (rE.coli) infections can spread rapidly. Further they are associated with high morbidity and mortality from treatment failure. Therapy involves multiple rounds of ineffective antibiotics alongside unwanted side effects, alternative treatments are crucial. Apple cider vinegar (ACV) is a natural, vegan product that has been shown to have powerful antimicrobial activity hence we investigated whether ACV could ameliorate these resistant bacteria. The minimum dilution of ACV required for growth inhibition was comparable for both bacteria (1/25 dilution of ACV liquid and ACV tablets at 200 µg/ml were effective against rE. coli and MRSA). Monocyte co-culture with microbes alongside ACV resulted in an increase in monocyte phagocytosis by 21.2% and 33.5% compared to non-ACV treated but MRSA or rE. coli stimulated monocytes, respectively. Label free quantitative proteomic studies of microbial protein extracts demonstrated that ACV penetrated microbial cell membranes and organelles, altering the expression of key proteins. This resulted in significant reductions in total protein expression, moreover we could only detect ribosomal proteins; 50 s 30 s, enolase, phosphenol pyruvate and the ATP synthase subunit in rE. coli. Elongation factor iNOS and phosphoglycerate kinase OS were the only proteins present in MRSA samples following ACV treatment.
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4
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Bogart JW, Kramer NJ, Turlik A, Bleich RM, Catlin DS, Schroeder FC, Nair SK, Williamson RT, Houk KN, Bowers AA. Interception of the Bycroft-Gowland Intermediate in the Enzymatic Macrocyclization of Thiopeptides. J Am Chem Soc 2020; 142:13170-13179. [PMID: 32609512 PMCID: PMC7429253 DOI: 10.1021/jacs.0c05639] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Thiopeptides are a broad class of macrocyclic, heavily modified peptide natural products that are unified by the presence of a substituted, nitrogen-containing heterocycle core. Early work indicated that this core might be fashioned from two dehydroalanines by an enzyme-catalyzed aza-[4 + 2] cycloaddition to give a cyclic-hemiaminal intermediate. This common intermediate could then follow a reductive path toward a dehydropiperidine, as in the thiopeptide thiostrepton, or an aromatization path to yield the pyridine groups observed in many other thiopeptides. Although several of the enzymes proposed to perform this cycloaddition have been reconstituted, only pyridine products have been isolated and any hemiaminal intermediates have yet to be observed. Here, we identify the conditions and substrates that decouple the cycloaddition from subsequent steps and allow interception and characterization of this long hypothesized intermediate. Transition state modeling indicates that the key amide-iminol tautomerization is the major hurdle in an otherwise energetically favorable cycloaddition. An anionic model suggests that deprotonation and polarization of this amide bond by TbtD removes this barrier and provides a sufficient driving force for facile (stepwise) cycloaddition. This work provides evidence for a mechanistic link between disparate cyclases in thiopeptide biosynthesis.
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Affiliation(s)
- Jonathan W. Bogart
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Nicholas J. Kramer
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Aneta Turlik
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
| | - Rachel M. Bleich
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
| | - Daniel S. Catlin
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
| | - Frank C. Schroeder
- Boyce Thompson Institute and Department of Chemistry and Chemical Biology, Ithaca, New York 14853, USA
| | - Satish K. Nair
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Illinois 61801, USA
| | - R. Thomas Williamson
- Department of Chemistry and Biochemistry, University of North Carolina Wilmington, Wilmington, North Carolina 28403, USA
| | - K. N. Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
| | - Albert A. Bowers
- Division of Chemical Biology and Medicinal Chemistry, UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
- Department of Chemistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA
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5
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Natural thiopeptides as a privileged scaffold for drug discovery and therapeutic development. Med Chem Res 2019. [DOI: 10.1007/s00044-019-02361-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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6
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Bhatt R, Chudaev M, Mandecki W, Goldman E. Engineered EF-Tu and tRNA-Based FRET Screening Assay to Find Inhibitors of Protein Synthesis in Bacteria. Assay Drug Dev Technol 2018; 16:212-221. [DOI: 10.1089/adt.2018.843] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Rachana Bhatt
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, New Jersey
| | - Maxim Chudaev
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, New Jersey
| | - Wlodek Mandecki
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, New Jersey
| | - Emanuel Goldman
- Department of Microbiology, Biochemistry and Molecular Genetics, Rutgers New Jersey Medical School, Newark, New Jersey
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7
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Prezioso SM, Brown NE, Goldberg JB. Elfamycins: inhibitors of elongation factor-Tu. Mol Microbiol 2017; 106:22-34. [PMID: 28710887 DOI: 10.1111/mmi.13750] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/12/2017] [Indexed: 01/26/2023]
Abstract
Elfamycins are a relatively understudied group of antibiotics that target the essential process of translation through impairment of EF-Tu function. For the most part, the utility of these compounds has been as laboratory tools for the study of EF-Tu and the ribosome, as their poor pharmacokinetic profile and solubility has prevented implementation as therapeutic agents. However, due to the slowing of the antibiotic pipeline and the rapid emergence of resistance to approved antibiotics, this group is being reconsidered. Some researchers are using screens for novel naturally produced variants, while others are making directed, systematic chemical improvements on publically disclosed compounds. As an example of the latter approach, a GE2270 A derivative, LFF571, has completed phase 2 clinical trials, thus demonstrating the potential for elfamycins to become more prominent antibiotics in the future.
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Affiliation(s)
- Samantha M Prezioso
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Emory University School of Medicine, Atlanta, GA 30322, USA.,Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Nicole E Brown
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Joanna B Goldberg
- Division of Pulmonology, Allergy/Immunology, Cystic Fibrosis and Sleep, Department of Pediatrics, Emory University School of Medicine, Atlanta, GA 30322, USA.,Emory+Children's Center for Cystic Fibrosis and Airway Disease Research, Emory University School of Medicine, Atlanta, GA 30322, USA
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8
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9
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Burkhart BJ, Schwalen CJ, Mann G, Naismith JH, Mitchell DA. YcaO-Dependent Posttranslational Amide Activation: Biosynthesis, Structure, and Function. Chem Rev 2017; 117:5389-5456. [PMID: 28256131 DOI: 10.1021/acs.chemrev.6b00623] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
With advances in sequencing technology, uncharacterized proteins and domains of unknown function (DUFs) are rapidly accumulating in sequence databases and offer an opportunity to discover new protein chemistry and reaction mechanisms. The focus of this review, the formerly enigmatic YcaO superfamily (DUF181), has been found to catalyze a unique phosphorylation of a ribosomal peptide backbone amide upon attack by different nucleophiles. Established nucleophiles are the side chains of Cys, Ser, and Thr which gives rise to azoline/azole biosynthesis in ribosomally synthesized and posttranslationally modified peptide (RiPP) natural products. However, much remains unknown about the potential for YcaO proteins to collaborate with other nucleophiles. Recent work suggests potential in forming thioamides, macroamidines, and possibly additional post-translational modifications. This review covers all knowledge through mid-2016 regarding the biosynthetic gene clusters (BGCs), natural products, functions, mechanisms, and applications of YcaO proteins and outlines likely future research directions for this protein superfamily.
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Affiliation(s)
| | | | - Greg Mann
- Biomedical Science Research Complex, University of St Andrews , BSRC North Haugh, St Andrews KY16 9ST, United Kingdom
| | - James H Naismith
- Biomedical Science Research Complex, University of St Andrews , BSRC North Haugh, St Andrews KY16 9ST, United Kingdom.,State Key Laboratory of Biotherapy, Sichuan University , Sichuan, China
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10
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Brown P, Dawson MJ. A perspective on the next generation of antibacterial agents derived by manipulation of natural products. PROGRESS IN MEDICINAL CHEMISTRY 2014; 54:135-84. [PMID: 25727704 DOI: 10.1016/bs.pmch.2014.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Natural products have been a major source of anti-infective drugs for many decades. With urgent need for new antibacterial agents to combat drug-resistant bacteria, the investigation of both new and existing classes of natural products has once again become an important focus. In this review, we highlight how a medicinal chemistry/semi-synthetic approach to natural product manipulation continues to offer a valuable strategy to overcome limitations in current therapy. Approaches to address toxicity and to improve the solubility, bioavailability and the spectrum of activity are demonstrated. Examples are drawn from aminoglycosides, glycopeptides, tetracyclines, macrolides, thiazolyl peptides, pleuromutilins and polymyxins and are taken from the current literature, patents and abstracts of symposia. In many cases, this approach has led to drug candidates currently in late stages of clinical development.
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Affiliation(s)
- Pamela Brown
- Cantab Anti-infectives, Welwyn Garden City, Hertfordshire, United Kingdom
| | - Michael J Dawson
- Cantab Anti-infectives, Welwyn Garden City, Hertfordshire, United Kingdom
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11
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Just-Baringo X, Albericio F, Álvarez M. Engineering von Thiopeptiden: ein multidisziplinärer Weg zu neuen Wirkstoffen. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201307288] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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12
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Just-Baringo X, Albericio F, Álvarez M. Thiopeptide engineering: a multidisciplinary effort towards future drugs. Angew Chem Int Ed Engl 2014; 53:6602-16. [PMID: 24861213 DOI: 10.1002/anie.201307288] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2013] [Indexed: 11/12/2022]
Abstract
The recent development of thiopeptide analogues of antibiotics has allowed some of the limitations inherent to these naturally occurring substances to be overcome. Chemical synthesis, semisynthetic derivatization, and engineering of the biosynthetic pathway have independently led to complementary modifications of various thiopeptides. Some of the new substances have displayed improved profiles, not only as antibiotics, but also as antiplasmodial and anticancer drugs. The design of novel molecules based on the thiopeptide scaffold appears to be the only strategy to exploit the high potential they have shown in vitro. Herein we present the most relevant achievements in the production of thiopeptide analogues and also discuss the way the different approaches might be combined in a multidisciplinary strategy to produce more sophisticated structures.
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Affiliation(s)
- Xavier Just-Baringo
- Institute for Research in Biomedicine, Barcelona Science Park, University of Barcelona, Baldiri Reixac 10, 08028 Barcelona (Spain) http://www.pcb.ub.edu/fama/htm/home.htm; CIBER-BBN, Networking Centre on Bioengineering Biomaterials and Nanomedicine, 08028 Barcelona (Spain)
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13
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Wang D, Luo B, Shan W, Hao M, Sun X, Ge R. The effects of EF-Ts and bismuth on EF-Tu in Helicobacter pylori: implications for an elegant timing for the introduction of EF-Ts in the elongation and EF-Tu as a potential drug target. Metallomics 2014; 5:888-95. [PMID: 23765120 DOI: 10.1039/c3mt20265h] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Helicobacter pylori is a common human pathogen responsible for various gastric diseases. Bismuth can effectively inhibit the growth of this bacterium and is commonly recommended for the treatment of the related diseases. Translation elongation factors EF-Tu and EF-Ts are two important components of the protein translation system. EF-Ts has inhibitory effects on the GTPase activity of EF-Tu and enhances GDP release, a hint that careful timing for the introduction of EF-Ts in the elongation should be accomplished to prevent the complete inhibition of the elongation process. Bismuth inhibits the chaperone activity of EF-Tu, and has opposite effects on the elongation activity: inhibitory effects on the intrinsic GTPase activity and stimulation of GDP release. The present work deepens our understanding of the bacterial elongation process as mediated by EF-Tu and EF-Ts and extends our knowledge about the inhibitory effects of bismuth-based drugs against Helicobacter pylori.
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Affiliation(s)
- Dongxian Wang
- Key Laboratory of Gene Engineering of the Ministry of Education and State Key Laboratory of Biocontrol, College of Life Sciences, Sun Yat-Sen University, Guangzhou, China
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14
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Gross S, Nguyen F, Bierschenk M, Sohmen D, Menzel T, Antes I, Wilson DN, Bach T. Amythiamicin D and related thiopeptides as inhibitors of the bacterial elongation factor EF-Tu: modification of the amino acid at carbon atom C2 of ring C dramatically influences activity. ChemMedChem 2013; 8:1954-62. [PMID: 24106106 DOI: 10.1002/cmdc.201300323] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Indexed: 11/12/2022]
Abstract
Three analogues of amythiamicin D, which differ in the substitution pattern at the methine group adjacent to C2 of the thiazole ring C, were prepared by de novo total synthesis. In amythiamicin D, this carbon atom is (S)-isopropyl substituted. Two of the new analogues carry a hydroxymethyl in place of the isopropyl group, one at an S- (compound 3 a) and the other at an R-configured stereogenic center (3 b). The third analogue, 3 c, contains a benzyloxymethyl group at an S-configured stereogenic center. Compounds 3 b and 3 c showed no inhibitory effect toward various bacterial strains, nor did they influence the translation of firefly luciferase. In stark contrast, compound 3 a inhibited the growth of Gram-positive bacteria Staphylococcus aureus (strains NCTC and Mu50) and Listeria monocytogenes EGD. In the firefly luciferase assay it proved more potent than amythiamicin D, and rescue experiments provided evidence that translation inhibition is due to binding to the bacterial elongation factor Tu (EF-Tu). The results were rationalized by structural investigations and by molecular dynamics simulations of the free compounds in solution and bound to the EF-Tu binding site. The low affinity of compound 3 b was attributed to the absence of a critical hydrogen bond, which stabilizes the conformation required for binding to EF-Tu. Compound 3 c was shown not to comply with the binding properties of the binding site.
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Affiliation(s)
- Stefan Gross
- Lehrstuhl für Organische Chemie I, Technische Universität München, Lichtenbergstr. 4, 85747 Garching (Germany)
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15
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Cloning and characterization of EF-Tu and EF-Ts from Pseudomonas aeruginosa. BIOMED RESEARCH INTERNATIONAL 2013; 2013:585748. [PMID: 23984384 PMCID: PMC3747624 DOI: 10.1155/2013/585748] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 07/12/2013] [Indexed: 11/17/2022]
Abstract
We have cloned genes encoding elongation factors EF-Tu and EF-Ts from Pseudomonas aeruginosa and expressed and purified the proteins to greater than 95% homogeneity. Sequence analysis indicated that P. aeruginosa EF-Tu and EF-Ts are 84% and 55% identical to E. coli counterparts, respectively. P. aeruginosa EF-Tu was active when assayed in GDP exchange assays. Kinetic parameters for the interaction of EF-Tu with GDP in the absence of EF-Ts were observed to be K M = 33 μM, k cat (obs) = 0.003 s(-1), and the specificity constant k cat (obs)/K M was 0.1 × 10(-3) s(-1) μM(-1). In the presence of EF-Ts, these values were shifted to K M = 2 μM, k cat (obs) = 0.005 s(-1), and the specificity constant k(cat)(obs)/K M was 2.5 × 10(-3) s(-1) μM(-1). The equilibrium dissociation constants governing the binding of EF-Tu to GDP (K GDP) were 30-75 nM and to GTP (K GTP) were 125-200 nM. EF-Ts stimulated the exchange of GDP by EF-Tu 10-fold. P. aeruginosa EF-Tu was active in forming a ternary complex with GTP and aminoacylated tRNA and was functional in poly(U)-dependent binding of Phe-tRNA(Phe) at the A-site of P. aeruginosa ribosomes. P. aeruginosa EF-Tu was active in poly(U)-programmed polyphenylalanine protein synthesis system composed of all P. aeruginosa components.
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Young TS, Dorrestein PC, Walsh CT. Codon randomization for rapid exploration of chemical space in thiopeptide antibiotic variants. ACTA ACUST UNITED AC 2013; 19:1600-10. [PMID: 23261603 DOI: 10.1016/j.chembiol.2012.10.013] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 10/03/2012] [Accepted: 10/08/2012] [Indexed: 01/22/2023]
Abstract
Thiopeptide antibiotics exhibit a profound level of chemical diversity that is installed through cascades of posttranslational modifications on ribosomal peptides. Here, we present a technique to rapidly explore the chemical space of the thiopeptide GE37468 through codon randomization, yielding insights into thiopeptide maturation as well as structure and activity relationships. In this incarnation of the methodology, we randomized seven residues of the prepeptide-coding region, enabling the generation of 133 potential thiopeptide variants. Variant libraries were subsequently queried in two ways. First, high-throughput MALDI-TOF mass spectrometry was applied to colony-level expressions to sample mutants that permitted full maturation of the antibiotic. Second, the activity of producing mutants was detected in an antibiotic overlay assay. In total, 29 of the 133 variants produced mature compound, 12 of which retained antibiotic activity and 1 that had improved activity.
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Affiliation(s)
- Travis S Young
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 240 Longwood Avenue, Armenise 608, Boston, MA 02115, USA
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Abstract
INTRODUCTION Natural products have long been instrumental for discovering antibiotics, but many pharmaceutical companies abandoned this field and new antibiotics declined. In contrast, microbial resistance to current antibiotics has approached critical levels. AREAS COVERED This article gives historical perspectives by providing background about present-day economic realities and medical needs for antibiotic research, whose pipeline is mostly focused toward older known agents and newer semi-synthetic derivatives. Future research trends and projected technological developments open many innovative opportunities to discover novel antibacterials and find ways to control pathogenic bacteria without conventional antibiotics that provoke resistance. EXPERT OPINION The successful registration of daptomycin, retapamulin and fidaxomicin indicate the re-emergence of natural products has already begun. Semi-synthetic derivatives from other under-explored classes are progressing. More effort is being put into approaches such as total synthesis, discovery of new structural scaffolds for synthesis, alterations of biosynthetic pathways, combinatorial biosynthesis, new screening targets and new resources from which to isolate natural products. A return to successful screening of actinomycetes depends on solving the rate-limiting dereplication obstacle. Long-term solutions need to come from greater exploration of the massive numbers of uncultured microbes. An ultimate solution to the antibiotic-promoted microbial resistance cycle may lie in finding ways to control bacteria by non-lethal means.
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Leeds JA, Sachdeva M, Mullin S, Dzink-Fox J, Lamarche MJ. Mechanism of action of and mechanism of reduced susceptibility to the novel anti-Clostridium difficile compound LFF571. Antimicrob Agents Chemother 2012; 56:4463-5. [PMID: 22644023 PMCID: PMC3421628 DOI: 10.1128/aac.06354-11] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Accepted: 03/06/2012] [Indexed: 01/07/2023] Open
Abstract
LFF571 is a novel semisynthetic thiopeptide and potent inhibitor of Gram-positive bacteria. We report that the antibacterial activity of LFF571 against Clostridium difficile is due to inhibition of translation. Single-step mutants of C. difficile with reduced susceptibility to LFF571 were selected at frequencies of <4.5 × 10(-11) to 1.2 × 10(-9). Sequencing revealed a G260E substitution in the thiopeptide-binding pocket of elongation factor Tu. Importantly, this mutation did not confer cross-resistance to clinically used antimicrobials. These results support the development of LFF571 as a treatment for C. difficile infection.
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Affiliation(s)
- J A Leeds
- Novartis Institutes for Biomedical Research, Infectious Disease Area, Emeryville, California, USA.
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LaMarche MJ, Leeds JA, Amaral K, Brewer JT, Bushell SM, Dewhurst JM, Dzink-Fox J, Gangl E, Goldovitz J, Jain A, Mullin S, Neckermann G, Osborne C, Palestrant D, Patane MA, Rann EM, Sachdeva M, Shao J, Tiamfook S, Whitehead L, Yu D. Antibacterial Optimization of 4-Aminothiazolyl Analogues of the Natural Product GE2270 A: Identification of the Cycloalkylcarboxylic Acids. J Med Chem 2011; 54:8099-109. [DOI: 10.1021/jm200938f] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Akash Jain
- Chemical and Pharmaceutical
Profiling, Novartis Pharmaceuticals, Cambridge,
Massachusetts 02139, United States
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