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Jalali E, Wang F, Overbay BR, Miller MD, Shaaban KA, Ponomareva LV, Ye Q, Saghaeiannejad-Esfahani H, Bhardwaj M, Steele AD, Teijaro CN, Shen B, Van Lanen SG, She QB, Voss SR, Phillips GN, Thorson JS. Biochemical and Structural Studies of the Carminomycin 4- O-Methyltransferase DnrK. JOURNAL OF NATURAL PRODUCTS 2024. [PMID: 38412432 DOI: 10.1021/acs.jnatprod.3c00947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
Structural and functional studies of the carminomycin 4-O-methyltransferase DnrK are described, with an emphasis on interrogating the acceptor substrate scope of DnrK. Specifically, the evaluation of 100 structurally and functionally diverse natural products and natural product mimetics revealed an array of pharmacophores as productive DnrK substrates. Representative newly identified DnrK substrates from this study included anthracyclines, angucyclines, anthraquinone-fused enediynes, flavonoids, pyranonaphthoquinones, and polyketides. The ligand-bound structure of DnrK bound to a non-native fluorescent hydroxycoumarin acceptor, 4-methylumbelliferone, along with corresponding DnrK kinetic parameters for 4-methylumbelliferone and native acceptor carminomycin are also reported for the first time. The demonstrated unique permissivity of DnrK highlights the potential for DnrK as a new tool in future biocatalytic and/or strain engineering applications. In addition, the comparative bioactivity assessment (cancer cell line cytotoxicity, 4E-BP1 phosphorylation, and axolotl embryo tail regeneration) of a select set of DnrK substrates/products highlights the ability of anthracycline 4-O-methylation to dictate diverse functional outcomes.
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Affiliation(s)
| | - Fengbin Wang
- Department of Biosciences, Rice University, Houston, Texas 77030, United States
| | | | - Mitchell D Miller
- Department of Biosciences, Rice University, Houston, Texas 77030, United States
| | | | | | - Qing Ye
- Markey Cancer Center, Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, Kentucky 40536, United States
| | | | | | | | | | | | | | - Qing-Bai She
- Markey Cancer Center, Department of Pharmacology and Nutritional Sciences, College of Medicine, University of Kentucky, Lexington, Kentucky 40536, United States
| | - S Randal Voss
- Department of Neuroscience, University of Kentucky, Lexington, Kentucky 40536, United States
- Ambystoma Genetic Stock Center, University of Kentucky, Lexington, Kentucky 40536, United States
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536, United States
| | - George N Phillips
- Department of Biosciences, Rice University, Houston, Texas 77030, United States
- Department of Chemistry, Rice University, Houston, Texas 77030, United States
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2
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Izyani Awang AF, Ahmed QU, Shah SAA, Jaffri JM, Ghafoor K, Uddin ABMH, Ferdosh S, Islam Sarker MZ. Isolation and characterization of novel antibacterial compound from an untapped plant, Stereospermum fimbriatum. Nat Prod Res 2018; 34:629-637. [PMID: 30470132 DOI: 10.1080/14786419.2018.1494170] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Stereospermum fimbriatum or locally known as "Chicha" is traditionally used for itchy skin, earache, stomachache and postpartum treatments. This study was designed to evaluate the antimicrobial potential of S. fimbriatum's stem bark against 11 pathogens and isolate its bioactive compound. Successive soxhlet extraction was conducted using n-hexane, dichloromethane (DCM) and methanol. Disc diffusion, minimum inhibitory and bactericidal concentration (MIC & MBC) assays were done to examine the antimicrobial activity. Bioassay-guided isolation was conducted on S. fimbriatum's extract. The DCM extract of stem bark (DS) was the most potent extract followed by n-hexane extract of the stem bark (NS). A novel compound was isolated and coded as C1 which demonstrated potent antibacterial effects with the MIC values as low as 3.13 µg/mL to 6.25 µg/mL, against S. epidermidis, MRSA and S. aureus. Thus, S. fimbriatum could be a potential source of antimicrobial agents for the treatment of skin infections, specifically, MRSA.
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Affiliation(s)
| | - Qamar Uddin Ahmed
- Faculty of Pharmacy, International Islamic University Malaysia, Kuantan, Pahang, Malaysia
| | - Syed Adnan Ali Shah
- Faculty of Pharmacy, Universiti Teknologi MARA, Selangor D. E., Malaysia.,Atta-ur-Rahman Institute for Natural Products Discovery (AuRIns), Universiti Teknologi MARA, Selangor D. E., Malaysia
| | - Juliana Md Jaffri
- Faculty of Pharmacy, International Islamic University Malaysia, Kuantan, Pahang, Malaysia
| | - Kashif Ghafoor
- Department of Food and Nutrition Sciences, King Saud University, Riyadh, Saudi Arabia
| | - A B M Helal Uddin
- Faculty of Pharmacy, International Islamic University Malaysia, Kuantan, Pahang, Malaysia
| | - Sahena Ferdosh
- Faculty of Science, International Islamic University Malaysia, Kuantan, Pahang, Malaysia
| | - Md Zaidul Islam Sarker
- Faculty of Pharmacy, International Islamic University Malaysia, Kuantan, Pahang, Malaysia
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Akhter N, Liu Y, Auckloo BN, Shi Y, Wang K, Chen J, Wu X, Wu B. Stress-Driven Discovery of New Angucycline-Type Antibiotics from a Marine Streptomyces pratensis NA-ZhouS1. Mar Drugs 2018; 16:E331. [PMID: 30213076 PMCID: PMC6163593 DOI: 10.3390/md16090331] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 08/31/2018] [Accepted: 09/07/2018] [Indexed: 01/23/2023] Open
Abstract
Natural products from marine actinomycetes remain an important resource for drug discovery, many of which are produced by the genus, Streptomyces. However, in standard laboratory conditions, specific gene clusters in microbes have long been considered silent or covert. Thus, various stress techniques activated latent gene clusters leading to isolation of potential metabolites. This study focused on the analysis of two new angucycline antibiotics isolated from the culture filtrate of a marine Streptomyces pratensis strain NA-ZhouS1, named, stremycin A (1) and B (2) which were further determined based on spectroscopic techniques such as high resolution time of flight mass spectrometry (HR-TOF-MS), 1D, and 2D nuclear magnetic resonance (NMR) experiments. In addition, four other known compounds, namely, 2-[2-(3,5-dimethyl-2-oxo-cyclohexyl)-6-oxo-tetrahydro-pyran-4yl]-acetamide (3), cyclo[l-(4-hydroxyprolinyl)-l-leucine] (4), 2-methyl-3H-quinazoline-4-one (5), and menthane derivative, 3-(hydroxymethyl)-6-isopropyl-10,12-dioxatricyclo[7.2.1.0]dodec-4-en-8-one (6) were obtained and elucidated by means of 1D NMR spectrometry. Herein, we describe the "Metal Stress Technique" applied in the discovery of angucyclines, a distinctive class of antibiotics that are commonly encoded in microbiomes but have never been reported in "Metal Stress" based discovery efforts. Novel antibiotics 1 and 2 exhibited antimicrobial activities against Pseudomonas aeruginosa, methicillin resistant Staphylococcus aureus (MRSA), Klebsiella pneumonia, and Escherichia coli with equal minimum inhibitory concentration (MIC) values of 16 µg/mL, while these antibiotics showed inhibition against Bacillus subtilis at MIC value of approximately 8⁻16 µg/mL, respectively. As a result, the outcome of this investigation revealed that metal stress is an effective technique in unlocking the biosynthetic potential and resulting production of novel antibiotics.
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Affiliation(s)
- Najeeb Akhter
- Ocean College, Zhejiang University, Hangzhou 310058, China.
| | - Yaqin Liu
- Department of Chemistry, Zhejiang University, Hangzhou 301000, China.
| | | | - Yutong Shi
- Ocean College, Zhejiang University, Hangzhou 310058, China.
| | - Kuiwu Wang
- Department of Chemistry, Zhejiang Gongshang University, Hangzhou 310012, China.
| | - Juanjuan Chen
- Key Laboratory of Applied Marine Biotechnology, Ningbo University, Chinese Ministry of Education, Ningbo 315211, China.
| | - Xiaodan Wu
- Centre of Analysis and Measurement, Zhejiang University, Hangzhou 310058, China.
| | - Bin Wu
- Ocean College, Zhejiang University, Hangzhou 310058, China.
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4
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Abdelfattah MS, Elmallah MIY, Faraag AHI, Hebishy AMS, Ali NH. Heliomycin and tetracinomycin D: anthraquinone derivatives with histone deacetylase inhibitory activity from marine sponge-associated Streptomyces sp. SP9. 3 Biotech 2018; 8:282. [PMID: 29881660 DOI: 10.1007/s13205-018-1304-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/24/2018] [Indexed: 01/04/2023] Open
Abstract
Several actinomycetes strains were isolated from different marine sponges collected from the Red Sea shore in Egypt. The efficiency of their crude extracts to inhibit histone deacetylase (HDAC) enzyme was investigated in the nuclear extract of Hela cell line. The crude extract corresponding to Streptomyces sp. SP9 isolated from the marine sponge Pseudoceratina arabica showed a promising HDAC inhibitory activity with 64 and 81% at 50 and 100 µg/ml, respectively. The strain was identified as Streptomyces sp. by phylogenetic analyses based on its 16S rRNA gene sequence. The major compounds of Streptomyces sp. SP9 were isolated and purified by different chromatographic methods. The chemical structure of the isolated compounds was identified on the basis of their spectroscopic data including mass, 1H and 13C NMR, and by comparison with those of authenticated samples. Structures of compounds 1 and 2 were established as heliomycin and tetracenomycin D, respectively. These compounds exhibited HDAC inhibitory activities with IC50 values of 29.8 ± 0.04 µg/ml for heliomycin (1) and 10.9 ± 0.02 µg/ml for tetracenomycin D (2). A computational docking study for compounds 1 and 2 against HDAC1, HDAC2, and HDAC3 was performed to formulate a hypothetical mechanism by which the tested compounds inhibit HDAC. Tetracenomycin D (2) showed a good binding interactions with HDAC2 (- 5.230 kcal/mol) and HDAC3 (- 6.361 kcal/mol).
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Affiliation(s)
- Mohamed Saleh Abdelfattah
- 1Marine Natural Products Unit (MNPRU), Faculty of Science, Helwan University, Ain Helwan, 11795 Cairo, Egypt
- 2Chemistry Department, Faculty of Science, Helwan University, Ain Helwan, 11795 Cairo, Egypt
| | - Mohammed Ismail Youssef Elmallah
- 1Marine Natural Products Unit (MNPRU), Faculty of Science, Helwan University, Ain Helwan, 11795 Cairo, Egypt
- 2Chemistry Department, Faculty of Science, Helwan University, Ain Helwan, 11795 Cairo, Egypt
| | - Ahmed Hassan Ibrahim Faraag
- 3Botany and Microbiology Department, Faculty of Science, Helwan University, Ain Helwan, 11795 Cairo, Egypt
- 4Faculty of Science, Bioinformatics Center, Helwan University, Ain Helwan, 11795 Cairo, Egypt
| | - Ali Mohamed Salah Hebishy
- 1Marine Natural Products Unit (MNPRU), Faculty of Science, Helwan University, Ain Helwan, 11795 Cairo, Egypt
- 2Chemistry Department, Faculty of Science, Helwan University, Ain Helwan, 11795 Cairo, Egypt
| | - Neama Hassan Ali
- 2Chemistry Department, Faculty of Science, Helwan University, Ain Helwan, 11795 Cairo, Egypt
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Yixizhuoma, Ishikawa N, Abdelfattah MS, Ishibashi M. Elmenols C-H, new angucycline derivatives isolated from a culture of Streptomyces sp. IFM 11490. J Antibiot (Tokyo) 2017; 70:601-606. [DOI: 10.1038/ja.2016.158] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 11/25/2016] [Accepted: 11/29/2016] [Indexed: 01/01/2023]
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6
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Liu H, Xiao L, Wei J, Schmitz JC, Liu M, Wang C, Cheng L, Wu N, Chen L, Zhang Y, Lin X. Identification of Streptomyces sp. nov. WH26 producing cytotoxic compounds isolated from marine solar saltern in China. World J Microbiol Biotechnol 2013; 29:1271-8. [PMID: 23420111 DOI: 10.1007/s11274-013-1290-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Accepted: 02/10/2013] [Indexed: 11/28/2022]
Abstract
A moderately halophilic actinomycetes strain, designated as WH26, was isolated from Weihai Solar Saltern in China. The identification of the strain WH26 was performed by its morphological characteristics, physiological and biochemical tests as well as phylogenetic analysis based on 16S rRNA sequence comparison. The results showed that the nucleotide sequence of the 16S rRNA gene (1,677 bp) of the strain WH26 exhibited close similarity (97-99 %) with other Streptomyces 16S rRNA genes and the strain WH26 was identified to belong to the genus Streptomyces. An ethyl acetate extraction of Streptomyces sp. nov. WH26 demonstrated significant cellular toxicity. Two compounds, 8-O-methyltetrangulol and naphthomycin A were isolated from the extract via silica gel column chromatography and HPLC. These two compounds showed potent cytotoxic activity against several human tumor cell lines including A549, HeLa, BEL-7402 and HT-29. The present studies suggest that moderately halophilic actinomycetes may be a novel biological source for the discovery of anticancer agents.
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Affiliation(s)
- Haizhou Liu
- Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Rd, Qingdao, 266071, People's Republic of China
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Screening of mutant strain Streptomyces mediolani sp. AC37 for (−)-8-O-methyltetrangomycin production enhancement. J Microbiol 2012; 50:1014-23. [DOI: 10.1007/s12275-012-2025-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 07/20/2012] [Indexed: 10/27/2022]
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Kharel MK, Pahari P, Shepherd MD, Tibrewal N, Nybo SE, Shaaban KA, Rohr J. Angucyclines: Biosynthesis, mode-of-action, new natural products, and synthesis. Nat Prod Rep 2011; 29:264-325. [PMID: 22186970 DOI: 10.1039/c1np00068c] [Citation(s) in RCA: 250] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Covering: 1997 to 2010. The angucycline group is the largest group of type II PKS-engineered natural products, rich in biological activities and chemical scaffolds. This stimulated synthetic creativity and biosynthetic inquisitiveness. The synthetic studies used five different strategies, involving Diels-Alder reactions, nucleophilic additions, electrophilic additions, transition-metal mediated cross-couplings and intramolecular cyclizations to generate the angucycline frames. Biosynthetic studies were particularly intriguing when unusual framework rearrangements by post-PKS tailoring oxidoreductases occurred, or when unusual glycosylation reactions were involved in decorating the benz[a]anthracene-derived cores. This review follows our previous reviews, which were published in 1992 and 1997, and covers new angucycline group antibiotics published between 1997 and 2010. However, in contrast to the previous reviews, the main focus of this article is on new synthetic approaches and biosynthetic investigations, most of which were published between 1997 and 2010, but go beyond, e.g. for some biosyntheses all the way back to the 1980s, to provide the necessary context of information.
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Affiliation(s)
- Madan K Kharel
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, 789 S. Limestone Street, Lexington, Kentucky 40536-0596, USA
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Kallio P, Patrikainen P, Suomela JP, Mäntsälä P, Metsä-Ketelä M, Niemi J. Flavoprotein hydroxylase PgaE catalyzes two consecutive oxygen-dependent tailoring reactions in angucycline biosynthesis. Biochemistry 2011; 50:5535-43. [PMID: 21595438 DOI: 10.1021/bi200600k] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A simplified model system composed of a NADPH-dependent flavoprotein hydroxylase PgaE and a short-chain alcohol dehydrogenase/reductase (SDR) CabV was used to dissect a multistep angucycline modification redox cascade into several subreactions in vitro. We demonstrate that the two enzymes are sufficient for the conversion of angucycline substrate 2,3-dehydro-UWM6 to gaudimycin C. The flavoenzyme PgaE is shown to be responsible for two consecutive NADPH- and O(2)-dependent reactions, consistent with the enzyme-catalyzed incorporation of oxygen atoms at C-12 and C-12b in gaudimycin C. The two reactions do not significantly overlap, and the second catalytic cycle is initiated only after the original substrate 2,3-dehydro-UWM6 is nearly depleted. This allowed us to isolate the product of the first reaction at limiting NADPH concentrations and allowed the study of the qualitative and kinetic properties of the separated reactions. Dissection of the reaction cascade also allowed us to establish that the SDR reductase CabV catalyzes the final biosynthetic step, which is closely coupled to the second PgaE reaction. In the absence of CabV, the complete PgaE reaction leads invariably to product degradation, whereas in its presence, the reaction yields the final product, gaudimycin C. The result implies that the C-6 ketoreduction step catalyzed by CabV is required for stabilization of a reactive intermediate. The close relationship between PgaE and CabV would explain previous in vivo observations: why the absence of a reductase gene may result in the lack of C-12b-oxygenated species and, vice versa, why all C-12b-oxygenated angucyclines appear to have undergone reduction at position C-6.
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Affiliation(s)
- Pauli Kallio
- Department of Biochemistry and Food Chemistry, University of Turku, FIN-20014 Turku, Finland
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Abstract
Three novel members of angucycline family named N05WA963A (1), B (2) and D (4), together with a new anthracycline named N05WA963C (3) were isolated from the culture broth of Streptomyces sp. N05WA963. The structures were elucidated on the basis of comprehensive spectral data analysis. All four compounds have shown antiproliferative effects on a panel of cancer cell lines such as SW620, K-562, MDA-MB-231, YES-4, T-98 and U251SP.
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11
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Abdalla MA, Helmke E, Laatsch H. Fujianmycin C, A Bioactive Angucyclinone from a Marine Derived Streptomyces sp. B6219 [1]. Nat Prod Commun 2010. [DOI: 10.1177/1934578x1000501216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
From a marine-derived streptomycete, a new bioactive angucyclinone, fujianmycin C (1), has been isolated along with five known, metabolites fujianmycins A (2) and B (3), ochromycinone (4), ochromycinone methyl ether (5), and tetrangulol methyl ether (6). The structure elucidation of fujianmycin C (1) was performed by detailed analysis of data such as 1H, 13C, 1H,1H COSY, HSQC, HMBC and NOESY spectra. Fujianmycin C (1) exhibited antibacterial activity against Streptomyces viridochromogenes (Tü57).
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Affiliation(s)
- Muna Ali Abdalla
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, D-37077 Göttingen, Germany
| | - Elisabeth Helmke
- Alfred-Wegener-Institute for Polar and Marine Research, Am Handelshafen 12, D-2757, Bremerhaven, Germany
| | - Hartmut Laatsch
- Institute of Organic and Biomolecular Chemistry, University of Göttingen, Tammannstrasse 2, D-37077 Göttingen, Germany
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Maruna M, Sturdikova M, Liptaj T, Godany A, Muckova M, Certik M, Pronayova N, Proksa B. Isolation, structure elucidation and biological activity of angucycline antibiotics from an epiphytic yew streptomycete. J Basic Microbiol 2010; 50:135-42. [PMID: 20082376 DOI: 10.1002/jobm.200900227] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In the course of study of epiphytic microorganisms occurring on the surface of roots of Taxus baccata L. a new strain Streptomyces sp. AC113 was isolated. According to 16S ribosomal DNA-based identification the new strain is 99% identical with Streptomyces flavidofuscus. This strain cultivated in an arginine glycerol medium produced three major metabolites identified as (-)-8-O -methyltetrangomycin (1), 8-O -methyltetrangulol (2) and 8-O -methyl-7-deoxo-7-hydroxytetrangomycin (3). The chemical structures of these angucyclines were elucidated by 1D and 2D NMR as well as by mass spectrometry. Isolated angucycline metabolites showed significant antimicrobial activity against Bacillus cereus and Listeria mocytogenes. Cytotoxic activities of compounds 1, 2 and 3 against four cell lines (B16, HT-29 and non - tumor V79, L929) were evaluated. Compound 3 was the most potent anticancer agents with IC(50) 0.054 microg/ml against cell line B16.
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Affiliation(s)
- Michal Maruna
- Department of Biochemical Technology, Institute of Biotechnology and Food Science, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Slovak Republic.
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Abdelfattah MS. Mansoquinone: Isolation and structure elucidation of new antibacterial aromatic polyketides from terrestrialStreptomycesSp. Eg5. Nat Prod Res 2009; 23:212-8. [DOI: 10.1080/14786410801961550] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abdelfattah MS, Kharel MK, Hitron JA, Baig I, Rohr J. Moromycins A and B, isolation and structure elucidation of C-glycosylangucycline-type antibiotics from Streptomyces sp. KY002. JOURNAL OF NATURAL PRODUCTS 2008; 71:1569-73. [PMID: 18666798 PMCID: PMC2562265 DOI: 10.1021/np800281f] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Two new anticancer antibiotics of the angucycline class, moromycins A and B (1, 2), along with the known microbial metabolites saquayamycin B (3) and fridamycin D (4) were isolated from the ethyl acetate extract of a culture broth of the terrestrial Streptomyces sp. KY002. The structures consist of a tetrangomycin core and various C- and O-glycosidically linked deoxysugars. The chemical structures of the new secondary metabolites were elucidated by 1D and 2D NMR and by mass spectrometry. Moromycin B (2) showed significant cytotoxicity against H-460 human lung cancer and MCF-7 human breast cancer cells.
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Affiliation(s)
| | | | | | | | - Jürgen Rohr
- Corresponding author. E-mail:. Fax: 859-257-7564
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Kallio P, Liu Z, Mäntsälä P, Niemi J, Metsä-Ketelä M. Sequential action of two flavoenzymes, PgaE and PgaM, in angucycline biosynthesis: chemoenzymatic synthesis of gaudimycin C. ACTA ACUST UNITED AC 2008; 15:157-66. [PMID: 18291320 DOI: 10.1016/j.chembiol.2007.12.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 11/24/2007] [Accepted: 12/04/2007] [Indexed: 11/25/2022]
Abstract
Tailoring steps in aromatic polyketide antibiotic biosynthesis are an important source of structural diversity and, consequently, an intriguing focal point for enzymological studies. PgaE and PgaM from Streptomyces sp. PGA64 are representatives of flavoenzymes catalyzing early post-PKS reactions in angucycline biosynthesis. This in vitro study illustrates that the chemoenzymatic conversion of UWM6 into the metabolite, gaudimycin C, requires multiple closely coupled reactions to prevent intermediate degradation. The NMR structure of gaudimycin C confirms that the reaction cascade involves C12- and C12b-hydroxylation, C2,3-dehydration, and stereospecific ketoreduction at C6. Enzymatic 18O incorporation studies verify that the oxygens at C12 and C12b derive from O2 and H2O, respectively. The results indicate that PgaM deviates mechanistically from flavoprotein monooxygenases, and suggest an alternative catalytic mechanism involving a quinone methide intermediate.
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Affiliation(s)
- Pauli Kallio
- Department of Biochemistry and Food Chemistry, University of Turku, FIN-20014 Turku, Finland
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18
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Flatman RH, Howells AJ, Heide L, Fiedler HP, Maxwell A. Simocyclinone D8, an inhibitor of DNA gyrase with a novel mode of action. Antimicrob Agents Chemother 2005; 49:1093-100. [PMID: 15728908 PMCID: PMC549283 DOI: 10.1128/aac.49.3.1093-1100.2005] [Citation(s) in RCA: 94] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have characterized the interaction of a new class of antibiotics, simocyclinones, with bacterial DNA gyrase. Even though their structures include an aminocoumarin moiety, a key feature of novobiocin, coumermycin A(1), and clorobiocin, which also target gyrase, simocyclinones behave strikingly differently from these compounds. Simocyclinone D8 is a potent inhibitor of gyrase supercoiling, with a 50% inhibitory concentration lower than that of novobiocin. However, it does not competitively inhibit the DNA-independent ATPase reaction of GyrB, which is characteristic of other aminocoumarins. Simocyclinone D8 also inhibits DNA relaxation by gyrase but does not stimulate cleavage complex formation, unlike quinolones, the other major class of gyrase inhibitors; instead, it abrogates both Ca(2+)- and quinolone-induced cleavage complex formation. Binding studies suggest that simocyclinone D8 interacts with the N-terminal domain of GyrA. Taken together, our results demonstrate that simocyclinones inhibit an early step of the gyrase catalytic cycle by preventing binding of the enzyme to DNA. This is a novel mechanism for a gyrase inhibitor and presents new possibilities for antibacterial drug development.
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Affiliation(s)
- Ruth H Flatman
- Department of Biological Chemistry, John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, UK
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