1
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Fan PH, Sato S, Yeh YC, Liu HW. Biosynthetic Origin of the Octose Core and Its Mechanism of Assembly during Apramycin Biosynthesis. J Am Chem Soc 2023; 145:21361-21369. [PMID: 37733880 PMCID: PMC10591738 DOI: 10.1021/jacs.3c06354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/23/2023]
Abstract
Apramycin is an aminoglycoside antibiotic isolated from Streptoalloteichus tenebrarius and S. hindustanus that has found clinical use in veterinary medicine. The apramycin structure is notable for its atypical eight-carbon bicyclic dialdose (octose) moiety. While the apramycin biosynthetic gene cluster (apr) has been identified and several of the encoded genes functionally characterized, how the octose core itself is assembled has remained elusive. Nevertheless, recent gene deletion studies have hinted at an N-acetyl aminosugar being a key precursor to the octose, and this hypothesis is consistent with the additional feeding experiments described in the present report. Moreover, bioinformatic analysis indicates that AprG may be structurally similar to GlcNAc-2-epimerase and hence recognize GlcNAc or a structurally similar substrate suggesting a potential role in octose formation. AprG with an extended N-terminal sequence was therefore expressed, purified, and assayed in vitro demonstrating that it does indeed catalyze a transaldolation reaction between GlcNAc or GalNAc and 6'-oxo-lividamine to afford 7'-N-acetyldemethylaprosamine with the same 6'-R and 7'-S stereochemistry as those observed in the apramycin product. Biosynthesis of the octose core in apramycin thus proceeds in the [6 + 2] manner with GlcNAc or GalNAc as the two-carbon donor, which has not been previously reported for biological octose formation, as well as novel inverting stereochemistry of the transferred fragment. Consequently, AprG appears to be a new transaldolase that lacks any apparent sequence similarity to the currently known aldolases and catalyzes a transaldolation for which there is no established biological precedent.
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Affiliation(s)
- Po-Hsun Fan
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Shusuke Sato
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Yu-Cheng Yeh
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Hung-Wen Liu
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
- Division of Chemical Biology and Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, United States
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2
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Lee NJ, Kang W, Kwon Y, Oh JW, Jung H, Seo M, Seol Y, Wi JB, Ban YH, Yoon YJ, Park JW. Chemo-enzymatic Synthesis of Pseudo-trisaccharide Aminoglycoside Antibiotics with Enhanced Nonsense Read-through Inducer Activity. ChemMedChem 2023; 18:e202200497. [PMID: 36259357 DOI: 10.1002/cmdc.202200497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/18/2022] [Indexed: 01/24/2023]
Abstract
Aminoglycosides (AGs) are broad-spectrum antibiotics used to treat bacterial infections. Over the last two decades, studies have reported the potential of AGs in the treatment of genetic disorders caused by nonsense mutations, owing to their ability to induce the ribosomes to read through these mutations and produce a full-length protein. However, the principal limitation in the clinical application of AGs arises from their high toxicity, including nephrotoxicity and ototoxicity. In this study, five novel pseudo-trisaccharide analogs were synthesized by chemo-enzymatic synthesis by acid hydrolysis of commercially available AGs, followed by an enzymatic reaction using recombinant substrate-flexible KanM2 glycosyltransferase. The relationships between their structures and biological activities, including the antibacterial, nephrotoxic, and nonsense readthrough inducer (NRI) activities, were investigated. The absence of 1-N-acylation, 3',4'-dideoxygenation, and post-glycosyl transfer modifications on the third sugar moiety of AGs diminishes their antibacterial activities. The 3',4'-dihydroxy and 6'-hydroxy moieties regulate the in vitro nephrotoxicity of AGs in mammalian cell lines. The 3',4'-dihydroxy and 6'-methyl scaffolds are indispensable for the ex vivo NRI activity of AGs. Based on the alleviated in vitro antibacterial properties and nephrotoxicity, and the highest ex vivo NRI activity among the five compounds, a kanamycin analog (6'-methyl-3''-deamino-3''-hydroxykanamycin C) was selected as a novel AG hit for further studies on human genetic disorders caused by premature transcriptional termination.
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Affiliation(s)
- Na Joon Lee
- Department of Integrated Biomedical and Life Sciences, Korea University, 02841, Seoul (Republic of, Korea
| | - Woongshin Kang
- Transdisciplinary Major in Learning Health Systems, Department of Integrated Biomedical and Life Sciences, Korea University, 02841, Seoul (Republic of, Korea
| | - Younghae Kwon
- Transdisciplinary Major in Learning Health Systems, Department of Integrated Biomedical and Life Sciences, Korea University, 02841, Seoul (Republic of, Korea
| | - Jae Wook Oh
- Transdisciplinary Major in Learning Health Systems, Department of Integrated Biomedical and Life Sciences, Korea University, 02841, Seoul (Republic of, Korea
| | - Hogwuan Jung
- Transdisciplinary Major in Learning Health Systems, Department of Integrated Biomedical and Life Sciences, Korea University, 02841, Seoul (Republic of, Korea
| | - Minsuk Seo
- Transdisciplinary Major in Learning Health Systems, Department of Integrated Biomedical and Life Sciences, Korea University, 02841, Seoul (Republic of, Korea
| | - Yurin Seol
- Transdisciplinary Major in Learning Health Systems, Department of Integrated Biomedical and Life Sciences, Korea University, 02841, Seoul (Republic of, Korea
| | - Jae Bok Wi
- Department of Integrated Biomedical and Life Sciences, Korea University, 02841, Seoul (Republic of, Korea
| | - Yeon Hee Ban
- College of Pharmacy, Natural Products Research Institute, Seoul National University, 08826, Seoul (Republic of, Korea
| | - Yeo Joon Yoon
- College of Pharmacy, Natural Products Research Institute, Seoul National University, 08826, Seoul (Republic of, Korea
| | - Je Won Park
- Department of Integrated Biomedical and Life Sciences, Korea University, 02841, Seoul (Republic of, Korea.,School of Biosystems and Biomedical Sciences, Korea University, 02841, Seoul (Republic of, Korea
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3
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Obszynski J, Loidon H, Blanc A, Weibel JM, Pale P. Targeted modifications of neomycin and paromomycin: Towards resistance-free antibiotics? Bioorg Chem 2022; 126:105824. [DOI: 10.1016/j.bioorg.2022.105824] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 04/10/2022] [Accepted: 04/19/2022] [Indexed: 12/01/2022]
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4
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Wang J, Ma S, Ding W, Chen T, Zhang Q. Mechanistic Study of Oxidoreductase
AprQ
Involved in Biosynthesis of Aminoglycoside Antibiotic Apramycin. CHINESE J CHEM 2021. [DOI: 10.1002/cjoc.202100070] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Jinxiu Wang
- State Key Laboratory of Cryospheric Science, Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Northwest Institute of Eco‐Environment and Resources, Chinese Academy of Sciences Lanzhou Gansu 730000 China
- Department of Chemistry, Fudan University Shanghai 200433 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Suze Ma
- Department of Chemistry, Fudan University Shanghai 200433 China
| | - Wei Ding
- State Key Laboratory of Microbial Metabolism, School of Life Sciences & Biotechnology, Shanghai Jiao Tong University Shanghai 200240 China
| | - Tuo Chen
- State Key Laboratory of Cryospheric Science, Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Northwest Institute of Eco‐Environment and Resources, Chinese Academy of Sciences Lanzhou Gansu 730000 China
| | - Qi Zhang
- Department of Chemistry, Fudan University Shanghai 200433 China
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5
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Zhang Q, Chi H, Wu L, Deng Z, Yu Y. Two Cryptic Self‐Resistance Mechanisms in
Streptomyces tenebrarius
Reveal Insights into the Biosynthesis of Apramycin. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202100687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Qian Zhang
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Hao‐Tian Chi
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Linrui Wu
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Zixin Deng
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Yi Yu
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
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6
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Zhang Q, Chi H, Wu L, Deng Z, Yu Y. Two Cryptic Self‐Resistance Mechanisms in
Streptomyces tenebrarius
Reveal Insights into the Biosynthesis of Apramycin. Angew Chem Int Ed Engl 2021; 60:8990-8996. [DOI: 10.1002/anie.202100687] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Indexed: 12/30/2022]
Affiliation(s)
- Qian Zhang
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Hao‐Tian Chi
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Linrui Wu
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Zixin Deng
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
| | - Yi Yu
- Key Laboratory of Combinatory Biosynthesis and Drug Discovery (Ministry of Education) School of Pharmaceutical Sciences Wuhan University Wuhan 430071 China
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7
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Chauhan S, Chaudhary P, Sharma V. Aggregation and Adsorption Behavior of Cationic Surfactants (Cetyltrimethylammonium Bromide and Dodecyltrimethylammonium Bromide) in Aqueous Solutions of Antibiotic Drug (Amikacin Sulphate) at Different Temperatures. J SURFACTANTS DETERG 2020. [DOI: 10.1002/jsde.12462] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Affiliation(s)
- Suvarcha Chauhan
- Department of Chemistry Himachal Pradesh University Shimla 5 India
| | - Poonam Chaudhary
- Department of Chemistry Himachal Pradesh University Shimla 5 India
| | - Vivek Sharma
- Department of Chemistry MLSM College Sundernagar Mandi India
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8
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Ren E, Zhang C, Li D, Pang X, Liu G. Leveraging metal oxide nanoparticles for bacteria tracing and eradicating. VIEW 2020. [DOI: 10.1002/viw.20200052] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Affiliation(s)
- En Ren
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine School of Public Health Xiamen University Xiamen China
| | - Chang Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine School of Public Health Xiamen University Xiamen China
| | - Dengfeng Li
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine School of Public Health Xiamen University Xiamen China
| | - Xin Pang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine School of Public Health Xiamen University Xiamen China
- Department of Magnetic Resonance Imaging The First Affiliated Hospital of Zhengzhou University Zhengzhou China
| | - Gang Liu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics & Center for Molecular Imaging and Translational Medicine School of Public Health Xiamen University Xiamen China
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9
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Mrugała B, Miłaczewska A, Porebski PJ, Niedzialkowska E, Guzik M, Minor W, Borowski T. A study on the structure, mechanism, and biochemistry of kanamycin B dioxygenase (KanJ)-an enzyme with a broad range of substrates. FEBS J 2020; 288:1366-1386. [PMID: 32592631 DOI: 10.1111/febs.15462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 04/09/2020] [Accepted: 06/09/2020] [Indexed: 02/06/2023]
Abstract
Kanamycin A is an aminoglycoside antibiotic isolated from Streptomyces kanamyceticus and used against a wide spectrum of bacteria, including Mycobacterium tuberculosis. Biosynthesis of kanamycin involves an oxidative deamination step catalyzed by kanamycin B dioxygenase (KanJ), thereby the C2' position of kanamycin B is transformed into a keto group upon release of ammonia. Here, we present for the first time, structural models of KanJ with several ligands, which along with the results of ITC binding assays and HPLC activity tests explain substrate specificity of the enzyme. The large size of the binding pocket suggests that KanJ can accept a broad range of substrates, which was confirmed by activity tests. Specificity of the enzyme with respect to its substrate is determined by the hydrogen bond interactions between the methylamino group of the antibiotic and highly conserved Asp134 and Cys150 as well as between hydroxyl groups of the substrate and Asn120 and Gln80. Upon antibiotic binding, the C terminus loop is significantly rearranged and Gln80 and Asn120, which are directly involved in substrate recognition, change their conformations. Based on reaction energy profiles obtained by density functional theory (DFT) simulations, we propose a mechanism of ketone formation involving the reactive FeIV = O and proceeding either via OH rebound, which yields a hemiaminal intermediate or by abstraction of two hydrogen atoms, which leads to an imine species. At acidic pH, the latter involves a lower barrier than the OH rebound, whereas at basic pH, the barrier leading to an imine vanishes completely. DATABASES: Structural data are available in PDB database under the accession numbers: 6S0R, 6S0T, 6S0U, 6S0W, 6S0V, 6S0S. Diffraction images are available at the Integrated Resource for Reproducibility in Macromolecular Crystallography at http://proteindiffraction.org under DOIs: 10.18430/m36s0t, 10.18430/m36s0u, 10.18430/m36s0r, 10.18430/m36s0s, 10.18430/m36s0v, 10.18430/m36s0w. A data set collection of computational results is available in the Mendeley Data database under DOI: 10.17632/sbyzssjmp3.1 and in the ioChem-BD database under DOI: 10.19061/iochem-bd-4-18.
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Affiliation(s)
- Beata Mrugała
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland
| | - Anna Miłaczewska
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland
| | - Przemyslaw Jerzy Porebski
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland.,Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Ewa Niedzialkowska
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland.,Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Maciej Guzik
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland
| | - Wladek Minor
- Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA, USA
| | - Tomasz Borowski
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Krakow, Poland
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10
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Ban YH, Song MC, Park JW, Yoon YJ. Minor components of aminoglycosides: recent advances in their biosynthesis and therapeutic potential. Nat Prod Rep 2020; 37:301-311. [DOI: 10.1039/c9np00041k] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
This Highlight covers the recent advances in the biosynthetic pathways of aminoglycosides including their minor components, together with the therapeutic potential for minor aminoglycoside components and semi-synthetic aminoglycosides.
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Affiliation(s)
- Yeon Hee Ban
- Department of Chemistry and Nanoscience
- Ewha Womans University
- Seoul 03760
- Republic of Korea
| | - Myoung Chong Song
- Department of Chemistry and Nanoscience
- Ewha Womans University
- Seoul 03760
- Republic of Korea
| | - Je Won Park
- School of Biosystems and Biomedical Sciences
- Korea University
- Seoul 02841
- Republic of Korea
| | - Yeo Joon Yoon
- Department of Chemistry and Nanoscience
- Ewha Womans University
- Seoul 03760
- Republic of Korea
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11
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Chang Y, Chai B, Ding Y, He M, Zheng L, Teng Y, Deng Z, Yu Y, Liu T. Overproduction of gentamicin B in industrial strain Micromonospora echinospora CCTCC M 2018898 by cloning of the missing genes genR and genS. Metab Eng Commun 2019; 9:e00096. [PMID: 31720212 PMCID: PMC6838515 DOI: 10.1016/j.mec.2019.e00096] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 07/01/2019] [Accepted: 07/18/2019] [Indexed: 01/28/2023] Open
Abstract
In pharmaceutical industry, isepamicin is mainly manufactured from gentamicin B, which is produced by Micromonospora echinospora as a minor component of the gentamicin complex. Improvement of gentamicin B production through metabolic engineering is therefore important to satisfy the increasing demand for isepamicin. We hypothesized that gentamicin B was generated from gentamicin JI-20A via deamination of the C2’ amino group. Using kanJ and kanK as the gene probes, we identified the putative deamination-related genes, genR and genS, through genome mining of the gentamicin B producing strain M. echinospora CCTCC M 2018898. Interestingly, genR and genS constitute a gene cassette located approximately 28.7 kb away from the gentamicin gene cluster. Gene knockout of genR and genS almost abolished the production of gentamicin B in the mutant strain, suggesting that these two genes, which are responsible for the last steps in gentamicin B biosynthesis, constitute the missing part of the known gentamicin biosynthetic pathway. Based on these finding, we successfully constructed a gentamicin B high-yielding strain (798 mg/L), in which an overexpression cassette of genR and genS was introduced. Our work fills the missing piece to solve the puzzle of gentamicin B biosynthesis and may inspire future metabolic engineering efforts to generate gentamycin B high-yielding strains that could eventually satisfy the need for industrial manufacturing of isepamicin. Two missing genes in the biosynthetic pathway of gentamicin B were found. CRISPR/Cas9 was applied successfully to delete genes in Micromonospora echinospora. Overexpression of genR/S cassette improved gentamicin B titer by 64% in current industrial strain.
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Affiliation(s)
- Yingying Chang
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China.,Hubei Engineering Laboratory for Synthetic Microbiology, Wuhan Institute of Biotechnology, Wuhan, 430075, China
| | - Baozhong Chai
- Zhejiang Key Laboratory of Antifungal Drugs, Zhejiang Hisun Pharmaceutical Co, Ltd, Taizhou, 318000, China
| | - Yunkun Ding
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China.,Hubei Engineering Laboratory for Synthetic Microbiology, Wuhan Institute of Biotechnology, Wuhan, 430075, China
| | - Min He
- Zhejiang Key Laboratory of Antifungal Drugs, Zhejiang Hisun Pharmaceutical Co, Ltd, Taizhou, 318000, China
| | - Linghui Zheng
- Zhejiang Key Laboratory of Antifungal Drugs, Zhejiang Hisun Pharmaceutical Co, Ltd, Taizhou, 318000, China
| | - Yun Teng
- Zhejiang Key Laboratory of Antifungal Drugs, Zhejiang Hisun Pharmaceutical Co, Ltd, Taizhou, 318000, China
| | - Zixin Deng
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China.,Hubei Engineering Laboratory for Synthetic Microbiology, Wuhan Institute of Biotechnology, Wuhan, 430075, China
| | - Yi Yu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China
| | - Tiangang Liu
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, Wuhan University School of Pharmaceutical Sciences, Wuhan, 430071, China.,Hubei Engineering Laboratory for Synthetic Microbiology, Wuhan Institute of Biotechnology, Wuhan, 430075, China
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12
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Complete reconstitution of the diverse pathways of gentamicin B biosynthesis. Nat Chem Biol 2019; 15:295-303. [PMID: 30643280 PMCID: PMC6488028 DOI: 10.1038/s41589-018-0203-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 11/13/2018] [Indexed: 11/13/2022]
Abstract
Gentamicin B (GB), a valuable starting material for the preparation of the semisynthetic aminoglycoside antibiotic isepamicin, is produced in trace amounts by the wild-type Micromonospora echinospora. While the biosynthetic pathway to GB has remained obscure for decades, we have now identified three hidden pathways to GB production via seven hitherto unknown intermediates in M. echinospora. The narrow substrate specificity of a key glycosyltransferase and the C6′-amination enzymes, in combination with the weak and unsynchronized gene expression of the 2′-deamination enzymes, limit GB production in M. echinospora. The crystal structure of the aminotransferase involved in C6′-amination explains its substrate specificity. Some of the new intermediates displayed similar premature termination codon readthrough activity but with reduced toxicity compared to the natural aminoglycoside G418. This work not only led to the discovery of unknown biosynthetic routes to GB, but also demonstrated the potential to mine new aminoglycosides from nature for drug discovery.
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13
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Amikacin: Uses, Resistance, and Prospects for Inhibition. Molecules 2017; 22:molecules22122267. [PMID: 29257114 PMCID: PMC5889950 DOI: 10.3390/molecules22122267] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 12/13/2017] [Accepted: 12/14/2017] [Indexed: 12/16/2022] Open
Abstract
Aminoglycosides are a group of antibiotics used since the 1940s to primarily treat a broad spectrum of bacterial infections. The primary resistance mechanism against these antibiotics is enzymatic modification by aminoglycoside-modifying enzymes that are divided into acetyl-transferases, phosphotransferases, and nucleotidyltransferases. To overcome this problem, new semisynthetic aminoglycosides were developed in the 70s. The most widely used semisynthetic aminoglycoside is amikacin, which is refractory to most aminoglycoside modifying enzymes. Amikacin was synthesized by acylation with the l-(-)-γ-amino-α-hydroxybutyryl side chain at the C-1 amino group of the deoxystreptamine moiety of kanamycin A. The main amikacin resistance mechanism found in the clinics is acetylation by the aminoglycoside 6'-N-acetyltransferase type Ib [AAC(6')-Ib], an enzyme coded for by a gene found in integrons, transposons, plasmids, and chromosomes of Gram-negative bacteria. Numerous efforts are focused on finding strategies to neutralize the action of AAC(6')-Ib and extend the useful life of amikacin. Small molecules as well as complexes ionophore-Zn+2 or Cu+2 were found to inhibit the acetylation reaction and induced phenotypic conversion to susceptibility in bacteria harboring the aac(6')-Ib gene. A new semisynthetic aminoglycoside, plazomicin, is in advance stage of development and will contribute to renewed interest in this kind of antibiotics.
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