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Genome mining Streptomyces sp. KCTC 0041BP as a producer of dihydrochalcomycin. Appl Microbiol Biotechnol 2021; 105:5023-5037. [PMID: 34136924 DOI: 10.1007/s00253-021-11393-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Revised: 05/26/2021] [Accepted: 06/07/2021] [Indexed: 10/21/2022]
Abstract
Streptomyces sp. KCTC 0041BP, which was isolated from a soil sample in Cheolwon, Republic of Korea, is a dihydrochalcomycin producer. In this study, we obtained the genome of S. sp. KCTC 0041BP with 7.54 Mb genome size. antiSMASH and the dbCAN2 meta server predicted that the genome would contain 26 secondary metabolite biosynthetic gene clusters (BGCs) and 285 carbohydrate-active enzymes. Besides dihydrochalcomycin, 21 compounds were successfully identified from S. sp. KCTC 0041BP, and among them, the structure of 8 compounds were proven by high-resolution electrospray ionization mass spectrometry (HRESIMS) and nuclear magnetic resonance (NMR). The identification of chalcomycin analogs led to a better understanding of the biosynthetic pathway of dihydrochalcomycin/chalcomycin. From the analysis of cluster 2 and solvent selection, linearmycins were determined. Linearmycins showed antibacterial activity with both Gram-positive and Gram-negative bacteria and antifungal activity. One strain many compounds (OSMAC) strategy was applied to activate the salicylic acid production in this strain. A salicylic acid biosynthetic pathway was also predicted, but not by antiSMASH. These results showed that this strain can produce many useful compounds and potentially produce novel compounds with most secondary BGCs yet to be experimentally identified.
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Chalcomycins from Marine-Derived Streptomyces sp. and Their Antimicrobial Activities. Mar Drugs 2017; 15:md15060153. [PMID: 28555051 PMCID: PMC5484103 DOI: 10.3390/md15060153] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 05/10/2017] [Accepted: 05/22/2017] [Indexed: 01/24/2023] Open
Abstract
Dihydrochalcomycin (1) and chalcomycin (2), two known chalcomycins, and chalcomycin E (3), a new compound, were isolated from marine-derived Streptomyces sp. HK-2006-1. Their structures were elucidated by detailed spectroscopic and X-ray crystallographic analysis. The antimicrobial activities against Staphylococcus aureus, Escherichia coli, Candida albicans, and Aspergillus niger of 1–3 were evaluated. Compounds 1–2 exhibited activities against S. aureus with minimal inhibitory concentrations (MICs) of 32 µg/mL and 4 µg/mL, respectively. The fact that 1–2 showed stronger activity against S. aureus 209P than 3 indicated that the epoxy unit was important for antimicrobial activity. This structure–activity tendency of chalcomycins against S. aureus is different from that of aldgamycins reported in our previous research, which provide a valuable example for the phenomenon that 16-membered macrolides with different sugars do not have parallel structure–activity relationships.
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Wang CX, Ding R, Jiang ST, Tang JS, Hu D, Chen GD, Lin F, Hong K, Yao XS, Gao H. Aldgamycins J-O, 16-Membered Macrolides with a Branched Octose Unit from Streptomycetes sp. and Their Antibacterial Activities. JOURNAL OF NATURAL PRODUCTS 2016; 79:2446-2454. [PMID: 27690254 DOI: 10.1021/acs.jnatprod.6b00200] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Six new 16-membered macrolides with a rare branched octose unit, aldgamycins J-O (1-6), along with two known compounds, swalpamycin B (7) and chalcomycin (8), were isolated from Streptomyces sp. HK-2006-1. Their structures were determined by detailed spectroscopic and X-ray crystallographic analysis. Natural products containing branched sugar units are rare. Aldgaropyranose and decarboxylated aldgaropyranose are branched octoses, specifically aldgarose-type branched octose. Until now, only 11 compounds have been reported to contain an aldgarose-type branched octose. The discovery of aldgamycins J-O (1-6) adds new members of this type of natural product. All the compounds (1-8) herein were tested for antimicrobial activities against Gram-positive Staphylococcus aureus 209P, Gram-negative Escherichia coli ATCC0111, and two fungi, Candida albicans FIM709 and Aspergillus niger R330. Most of these compounds showed antibacterial activity against S. aureus. Their preliminary structure-activity relationships are proposed.
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Affiliation(s)
- Chuan-Xi Wang
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University , Guangzhou 510632, People's Republic of China
| | - Rong Ding
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University , Guangzhou 510632, People's Republic of China
| | - Shu-Tai Jiang
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University , Guangzhou 510632, People's Republic of China
| | - Jin-Shan Tang
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University , Guangzhou 510632, People's Republic of China
| | - Dan Hu
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University , Guangzhou 510632, People's Republic of China
| | - Guo-Dong Chen
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University , Guangzhou 510632, People's Republic of China
| | - Feng Lin
- Fujian Key Laboratory of Screening for Novel Microbial Products, Fujian Institute of Microbiology , Fuzhou 350007, People's Republic of China
| | - Kui Hong
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery (Wuhan University), Ministry of Education, and Wuhan University School of Pharmaceutical Sciences , Wuhan 430071, People's Republic of China
| | - Xin-Sheng Yao
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University , Guangzhou 510632, People's Republic of China
| | - Hao Gao
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University , Guangzhou 510632, People's Republic of China
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Tang XL, Dai P, Gao H, Wang CX, Chen GD, Hong K, Hu D, Yao XS. A Single Gene Cluster for Chalcomycins and Aldgamycins: Genetic Basis for Bifurcation of Their Biosynthesis. Chembiochem 2016; 17:1241-9. [PMID: 27191535 DOI: 10.1002/cbic.201600118] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2016] [Indexed: 01/27/2023]
Abstract
Aldgamycins are 16-membered macrolide antibiotics with a rare branched-chain sugar d-aldgarose or decarboxylated d-aldgarose at C-5. In our efforts to clone the gene cluster for aldgamycins from a marine-derived Streptomyces sp. HK-2006-1 capable of producing both aldgamycins and chalcomycins, we found that both are biosynthesized from a single gene cluster. Whole-genome sequencing combined with gene disruption established the entire gene cluster of aldgamycins: nine new genes are incorporated with the previously identified chalcomycin gene cluster. Functional analysis of these genes revealed that almDI/almDII, (encoding α/β subunits of pyruvate dehydrogenase) triggers the biosynthesis of aldgamycins, whereas almCI (encoding an oxidoreductase) initiates chalcomycins biosynthesis. This is the first report that aldgamycins and chalcomycins are derived from a single gene cluster and of the genetic basis for bifurcation in their biosynthesis.
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Affiliation(s)
- Xiao-Long Tang
- College of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, No. 103 Wenhua Road, Shenyang, 110016, China
| | - Ping Dai
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, No. 601 Huangpu Avenue, Guangzhou, 510632, China
| | - Hao Gao
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, No. 601 Huangpu Avenue, Guangzhou, 510632, China
| | - Chuan-Xi Wang
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, No. 601 Huangpu Avenue, Guangzhou, 510632, China
| | - Guo-Dong Chen
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, No. 601 Huangpu Avenue, Guangzhou, 510632, China
| | - Kui Hong
- Key Laboratory of Combinatorial Biosynthesis and Drug Discovery, Ministry of Education, School of Pharmaceutical Sciences, Wuhan University, No. 185 Donghu Road, Wuhan, 430071, China
| | - Dan Hu
- Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, No. 601 Huangpu Avenue, Guangzhou, 510632, China.
| | - Xin-Sheng Yao
- College of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, No. 103 Wenhua Road, Shenyang, 110016, China. .,Institute of Traditional Chinese Medicine and Natural Products, College of Pharmacy, Jinan University, No. 601 Huangpu Avenue, Guangzhou, 510632, China.
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Elshahawi SI, Shaaban KA, Kharel MK, Thorson JS. A comprehensive review of glycosylated bacterial natural products. Chem Soc Rev 2015; 44:7591-697. [PMID: 25735878 PMCID: PMC4560691 DOI: 10.1039/c4cs00426d] [Citation(s) in RCA: 299] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A systematic analysis of all naturally-occurring glycosylated bacterial secondary metabolites reported in the scientific literature up through early 2013 is presented. This comprehensive analysis of 15 940 bacterial natural products revealed 3426 glycosides containing 344 distinct appended carbohydrates and highlights a range of unique opportunities for future biosynthetic study and glycodiversification efforts.
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Affiliation(s)
- Sherif I Elshahawi
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA. and Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, Lexington, KY, USA
| | - Khaled A Shaaban
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA. and Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, Lexington, KY, USA
| | - Madan K Kharel
- School of Pharmacy, University of Maryland Eastern Shore, Princess Anne, Maryland, USA
| | - Jon S Thorson
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, KY, USA. and Center for Pharmaceutical Research and Innovation, College of Pharmacy, University of Kentucky, Lexington, KY, USA
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Kubiak RL, Phillips RK, Zmudka MW, Ahn MR, Maka EM, Pyeatt GL, Roggensack SJ, Holden HM. Structural and functional studies on a 3'-epimerase involved in the biosynthesis of dTDP-6-deoxy-D-allose. Biochemistry 2012; 51:9375-83. [PMID: 23116432 DOI: 10.1021/bi3012737] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Unusual deoxy sugars are often attached to natural products such as antibiotics, antifungals, and chemotherapeutic agents. One such sugar is mycinose, which has been found on the antibiotics chalcomycin and tylosin. An intermediate in the biosynthesis of mycinose is dTDP-6-deoxy-D-allose. Four enzymes are required for the production of dTDP-6-deoxy-D-allose in Streptomyces bikiniensis, a soil-dwelling microbe first isolated from the Bikini and Rongelap atolls. Here we describe a combined structural and functional study of the enzyme ChmJ, which reportedly catalyzes the third step in the pathway leading to dTDP-6-deoxy-D-allose formation. Specifically, it has been proposed that ChmJ is a 3'-epimerase that converts dTDP-4-keto-6-deoxyglucose to dTDP-4-keto-6-deoxyallose. This activity, however, has never been verified in vitro. As reported here, we demonstrate using (1)H nuclear magnetic resonance that ChmJ, indeed, functions as a 3'-epimerase. In addition, we determined the structure of ChmJ complexed with dTDP-quinovose to 2.0 Å resolution. The structure of ChmJ shows that it belongs to the well-characterized "cupin" superfamily. Two active site residues, His 60 and Tyr 130, were subsequently targeted for study via site-directed mutagenesis and kinetic analyses, and the three-dimensional architecture of the H60N/Y130F mutant protein was determined to 1.6 Å resolution. Finally, the structure of the apoenzyme was determined to 2.2 Å resolution. It has been previously suggested that the position of a conserved tyrosine, Tyr 130 in the case of ChmJ, determines whether an enzyme in this superfamily functions as a mono- or diepimerase. Our results indicate that the orientation of the tyrosine residue in ChmJ is a function of the ligand occupying the active site cleft.
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Affiliation(s)
- Rachel L Kubiak
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin 53706, United States
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Identification and characterization of gerPI and gerPII involved in epoxidation and hydroxylation of dihydrochalcolactone in Streptomyces species KCTC 0041BP. Arch Microbiol 2010; 193:95-103. [PMID: 21069297 DOI: 10.1007/s00203-010-0648-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2009] [Revised: 09/16/2010] [Accepted: 10/21/2010] [Indexed: 10/18/2022]
Abstract
The macrolide antibiotics are biosynthesized by initial assembly of a macrolactone ring, followed by a series of post-polyketide (PKS) modifications. In general, the additional hydroxyl or epoxy groups are installed by cytochrome P450 enzymes, improving the bioactivity profile through structural diversification of natural products. The biosynthetic gene cluster for the 16-membered macrolide antibiotic dihydrochalcomycin (DHC) has been cloned from Streptomyces sp. KCTC 0041BP. Three cytochrome P450 genes are found in the DHC biosynthetic gene (ger) cluster. Two P450 enzymes were characterized from this cluster. Disruption of gerPI accumulated predominantly 12,13-de-epoxydihydrochalcomycin while disruption of gerPII accumulated 8-dehydroxy-12,13-de-epoxydihydrochalcomycin; DHC production was abolished in both cases. The results suggest that GerPII P450 catalyzes hydroxylation at the C(8) position followed by an epoxidation reaction catalyzed by GerPI P450 at the C(12)-C(13) position.
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Pageni BB, Simkhada D, Oh TJ, Sohng JK. Biosynthesis of dihydrochalcomycin: characterization of a deoxyallosyltransferase (gerGTI). Mol Cells 2010; 29:153-8. [PMID: 20069384 DOI: 10.1007/s10059-010-0019-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2009] [Revised: 10/20/2009] [Accepted: 10/28/2009] [Indexed: 11/30/2022] Open
Abstract
Through an inactivation experiment followed by complementation, the gerGTII gene was previously characterized as a chalcosyltransferase gene involved in the biosynthesis of dihydochalcomycin. The glycosyltransferase gerGTI was identified as a deoxyallosyltransferase required for the glycosylation of D-mycinose sugar. This 6-deoxyhexose sugar was converted to mycinose, via bis-O-methylation, following attachment to the polyketide lactone during dihydrochalcomycin biosynthesis. Gene sequence alignment of gerGTI to several glycosyltransferases revealed a consensus sequence motif that appears to be characteristic of the enzymes in this sub-group of the glycosyltransferase family. To characterize its putative function, genetic disruption of gerGTI in the wild-type strain Streptomyces sp. KCTC 0041BP and in the gerGTII-deleted mutant (S. sp. Delta gerGTsss, as well as complementation of gerGTII in S. sp. Delta gerGTss-GTs, were carried out, and the products were analyzed by LC/MS. S. sp. Delta gerGTss-GTs mutant produced dihydrochalconolide macrolide. S. sp. Delta gerGTs and S. sp. Delta gerGTss-GTs complementation of gerGTII yielded dihydrochalconolide without the mycinose sugar. The intermediate shows that gerGTI encodes a deoxyallosyltransferase that acts after gerGTII.
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Affiliation(s)
- Binod Babu Pageni
- Institute of Biomolecule Reconstruction, Department of Pharmaceutical Engineering, Sun Moon University, Asan 336-708, Korea
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Pageni BB, Oh TJ, Sohng JK. Novel desosaminyl derivatives of dihydrochalcomycin from a genetically engineered strain of Streptomyces sp. Biotechnol Lett 2009; 31:1759-68. [PMID: 19590827 DOI: 10.1007/s10529-009-0074-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 06/16/2009] [Accepted: 06/19/2009] [Indexed: 11/30/2022]
Abstract
Dihydrochalcomycin from Streptomyces sp. KCTC 0041BP is a 16-membered macrolide antibiotic containing two deoxysugars (D-chalcose and D-mycinose) that are O-glycosylated at the C-5 and C-20 positions, respectively. The desosamine sugar cassette was constructed from pikromycin-deoxysugar biosynthetic genes and transformed into Streptomyces sp. GerSM1, which was engineered for deletion of the genes related to TDP-D-chalcose biosynthesis (gerB, gerN and gerMI). Novel 16-membered macrolides (5-O-desosaminyl derivatives of dihydrochalcomycin) were detected by ESI-MS, LC/MS, and MS/MS thereby demonstrating combinatorial biosynthesis of the deoxysugar in 16-membered macrolide antibiotics.
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Affiliation(s)
- Binod Babu Pageni
- Institute of Biomolecule Reconstruction, Department of Pharmaceutical Engineering, SunMoon University, #100, Kalsan-ri, Tangjeong-myeon, Asansi, Chungnam, 336-708, Korea
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Simkhada D, Oh TJ, Pageni BB, Lee HC, Liou K, Sohng JK. Characterization of CalS9 in the biosynthesis of UDP-xylose and the production of xylosyl-attached hybrid compound. Appl Microbiol Biotechnol 2009; 83:885-95. [PMID: 19290519 DOI: 10.1007/s00253-009-1941-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Revised: 03/02/2009] [Accepted: 03/03/2009] [Indexed: 11/29/2022]
Abstract
The gene cluster of calicheamicin contains calS9, which encodes UDP-GlcA decarboxylase that converts UDP-GlcA to UDP-xylose. calS9 was cloned in pET32a(+) and expressed in Escherichia coli BL21 (DE3) to characterize its putative function. The reaction product was analyzed by high-performance liquid chromatography (HPLC) and electrospray ionization-mass spectrometry. The deoxysugar biosynthesis of Streptomyces sp. KCTC 0041BP was inactivated by gene replacement to generate Streptomyces sp. GerSM2 mutant, which was unable to produce dihydrochalcomycin. calS7, calS8, and calS9 UDP-xylose biosynthetic genes were cloned in an integrative plasmid pSET152 to generate pBPDS, which was heterologously expressed in Streptomyces sp. GerSM2. Finally, novel glycosylated product, 5-O-xylosyl-chalconolide derivative, in the conjugal transformants was isolated and analyzed by HPLC and liquid chromatography-mass spectrometry.
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Affiliation(s)
- Dinesh Simkhada
- Institute of Biomolecule Reconstruction, Department of Pharmaceutical Engineering, SunMoon University, Kalsan-ri, Tangjeong-myeon, Asansi, Chungnam, Republic of Korea
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Park JS, Yang HO, Kwon HC. Aldgamycin I, an antibacterial 16-membered macrolide from the abandoned mine bacterium, Streptomyces sp. KMA-001. J Antibiot (Tokyo) 2009; 62:171-5. [PMID: 19218982 DOI: 10.1038/ja.2009.6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Jin-Soo Park
- Natural Products Research Center, Korea Institute of Science and Technology, Gangneung, Gangwon-do, Republic of Korea
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Ding L, Qin S, Li F, Laatsch H. Novel chacolmycins possessing an amino sugar unit isolated from the marine Streptomyces sp. M491. J Biotechnol 2008. [DOI: 10.1016/j.jbiotec.2008.07.1365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ward SL, Hu Z, Schirmer A, Reid R, Revill WP, Reeves CD, Petrakovsky OV, Dong SD, Katz L. Chalcomycin biosynthesis gene cluster from Streptomyces bikiniensis: novel features of an unusual ketolide produced through expression of the chm polyketide synthase in Streptomyces fradiae. Antimicrob Agents Chemother 2005; 48:4703-12. [PMID: 15561847 PMCID: PMC529187 DOI: 10.1128/aac.48.12.4703-4712.2004] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chalcomycin, a 16-membered macrolide antibiotic made by the bacterium Streptomyces bikiniensis, contains a 2,3-trans double bond and the neutral sugar D-chalcose in place of the amino sugar mycaminose found in most other 16-membered macrolides. Degenerate polyketide synthase (PKS)-specific primers were used to amplify DNA fragments from S. bikiniensis with very high identity to a unique ketosynthase domain of the tylosin PKS. The resulting amplimers were used to identify two overlapping cosmids encompassing the chm PKS. Sequencing revealed a contiguous segment of >60 kb carrying 25 putative genes for biosynthesis of the polyketide backbone, the two deoxysugars, and enzymes involved in modification of precursors of chalcomycin or resistance to it. The chm PKS lacks the ketoreductase and dehydratase domains in the seventh module expected to produce the 2,3-double bond in chalcomycin. Expression of PKS in the heterologous host Streptomyces fradiae, from which the tyl genes encoding the PKS had been removed, resulted in production of at least one novel compound, characterized as a 3-keto 16-membered macrolactone in equilibrium with its 3-trans enol tautomer and containing the sugar mycaminose at the C-5 position, in agreement with the structure predicted on the basis of the domain organization of the chm PKS. The production of a 3-keto macrolide from the chm PKS indicates that a discrete set of enzymes is responsible for the introduction of the 2,3-trans double bond in chalcomycin. From comparisons of the open reading frames to sequences in databases, a pathway for the synthesis of nucleoside diphosphate-D-chalcose was proposed.
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Gotoh Y, Saitoh H, Miyake T. Chemical transformation of tylosin derivatives into neutral macrolides having a 3'-methoxyl group. Carbohydr Res 1998; 309:45-55. [PMID: 9720235 DOI: 10.1016/s0008-6215(98)00126-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This paper describes the chemical transformation of the basic 16-membered macrolides, tylosin derivatives, into neutral macrolides having a 3'-methoxyl group. 2',4'-Di-O-acetyl-3,23-bis(O-tert-butyldimethylsilyl)mycaminosyltylon olide 9,20-bis(ethylene acetal) N-oxide (1b) was treated with Ac2O-pyridine in CH2Cl2 to afford the 3'-ketone 1c and the 3'-N-acetyl-3'-N-demethyl derivative 1d in 67 and 5% yield; respectively. Reduction of 1c with Zn(BH4)2 gave the 3'-alcohol 1e in 84% yield stereoselectively. O-Methylation of 1e with MeOTf and 2,6-di-tert-butylpyridine gave the 3'-methyl ether 1f in 49% yield in spite of the presence of the adjacent acetoxyl groups. Deprotection of 1f provided the desired neutral macrolide 1g. Similar synthetic routes were also used for transformation of the suitably protected 4'-deoxymycaminosyltylonolide 2b and desmycosin 3c into neutral macrolides having a 3'-methoxyl group. It was found that the mycinose moiety of a neutral macrolide plays an important role in its antimicrobial activity.
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Affiliation(s)
- Y Gotoh
- Institute of Bioorganic Chemistry, Kawasaki, Japan
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