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Emma MG, Lombardo M, Trombini C, Quintavalla A. The Organocatalytic α-Fluorination of Chiral γ-Nitroaldehydes: the Challenge of Facing the Construction of a Quaternary Fluorinated Stereocenter. European J Org Chem 2016. [DOI: 10.1002/ejoc.201600378] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Marco Giuseppe Emma
- Department of Chemistry “G. Ciamician”; Alma Mater Studiorum; University of Bologna; Via Selmi 2 40126 Bologna Italy
| | - Marco Lombardo
- Department of Chemistry “G. Ciamician”; Alma Mater Studiorum; University of Bologna; Via Selmi 2 40126 Bologna Italy
| | - Claudio Trombini
- Department of Chemistry “G. Ciamician”; Alma Mater Studiorum; University of Bologna; Via Selmi 2 40126 Bologna Italy
| | - Arianna Quintavalla
- Department of Chemistry “G. Ciamician”; Alma Mater Studiorum; University of Bologna; Via Selmi 2 40126 Bologna Italy
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2
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Collet C, Chrétien F, Chapleur Y, Lamandé-Langle S. Diastereoselective synthesis of new O-alkylated and C-branched inositols and their corresponding fluoro analogues. Beilstein J Org Chem 2016; 12:353-61. [PMID: 26977196 PMCID: PMC4778503 DOI: 10.3762/bjoc.12.39] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 02/11/2016] [Indexed: 01/10/2023] Open
Abstract
Efficient routes were developed for the diastereoselective synthesis of new O-alkylated and C-branched inositols and their corresponding fluoro analogues. The key steps of the synthesis were the easy accessibility of different types of arms in term of configuration (myo and scyllo), the linking method and length, which could modulate the biological properties. These inositol derivatives, bearing an arm terminated either with a hydroxy group or a fluorine atom, could be interesting candidates for diastereoisomeric intermediates and biological evaluations, especially for PET imaging experiments.
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Affiliation(s)
- Charlotte Collet
- Université de Lorraine, Vandoeuvre-les-Nancy F-54500, France; CNRS, UMR 7565, Vandoeuvre-les-Nancy F-54506, France
| | - Françoise Chrétien
- Université de Lorraine, Vandoeuvre-les-Nancy F-54500, France; CNRS, UMR 7565, Vandoeuvre-les-Nancy F-54506, France
| | - Yves Chapleur
- Université de Lorraine, Vandoeuvre-les-Nancy F-54500, France; CNRS, UMR 7565, Vandoeuvre-les-Nancy F-54506, France
| | - Sandrine Lamandé-Langle
- Université de Lorraine, Vandoeuvre-les-Nancy F-54500, France; CNRS, UMR 7565, Vandoeuvre-les-Nancy F-54506, France
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3
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Kudo F, Eguchi T. Aminoglycoside Antibiotics: New Insights into the Biosynthetic Machinery of Old Drugs. CHEM REC 2015; 16:4-18. [PMID: 26455715 DOI: 10.1002/tcr.201500210] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Indexed: 11/07/2022]
Abstract
2-Deoxystreptamine (2DOS) is the unique chemically stable aminocyclitol scaffold of clinically important aminoglycoside antibiotics such as neomycin, kanamycin, and gentamicin, which are produced by Actinomycetes. The 2DOS core can be decorated with various deoxyaminosugars to make structurally diverse pseudo-oligosaccharides. After the discovery of biosynthetic gene clusters for 2DOS-containing aminoglycoside antibiotics, the function of each biosynthetic enzyme has been extensively elucidated. The common biosynthetic intermediates 2DOS, paromamine and ribostamycin are constructed by conserved enzymes encoded in the gene clusters. The biosynthetic intermediates are then converted to characteristic architectures by unique enzymes encoded in each biosynthetic gene cluster. In this Personal Account, we summarize both common biosynthetic pathways and the pathways used for structural diversification.
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Affiliation(s)
- Fumitaka Kudo
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Tadashi Eguchi
- Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
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4
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Joseph AA, Chang CW, Wang CC. Simple one-pot regioselective 6-O-phosphorylation of carbohydrates and trehalose desymmetrization. Chem Commun (Camb) 2014; 49:11497-9. [PMID: 24177789 DOI: 10.1039/c3cc47180b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Biologically essential carbohydrate 6-phosphates, especially trehalose 6-phosphate, can be synthesized easily in excellent overall yields in 2 steps involving minimum protecting group manipulations. We can cleave the diphenylphosphate group for further synthetic objectives.
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5
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Genes Encoding Carbocycle-Forming Enzymes Involved in Aminoglycoside Biosynthesis in Deep-Sea Environmental DNA. Biosci Biotechnol Biochem 2014; 74:1102-5. [DOI: 10.1271/bbb.90901] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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6
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Differences in the Roles of a Glutamine Amidotransferase Subunit of Pyridoxal 5'-Phosphate Synthase betweenBacillus circulansandBacillus subtilis. Biosci Biotechnol Biochem 2014; 77:1481-5. [DOI: 10.1271/bbb.130132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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7
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Abstract
Butirosin and neomycin belong to a family of clinically valuable 2-deoxystreptamine (2DOS)-containing aminoglycoside antibiotics. The biosynthetic gene clusters for butirosin and neomycin were identified in 2000 and in 2005, respectively. In recent years, most of the enzymes encoded in the gene clusters have been characterized, and thus almost all the biosynthetic steps leading to the final antibiotics have been understood. This knowledge could shed light on the complex biosynthetic pathways for other related structurally diverse aminoglycoside antibiotics. In this chapter, the enzymatic reactions in the biosynthesis of butirosin and neomycin are reviewed step by step.
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Affiliation(s)
- Fumitaka Kudo
- Department of Chemistry, Tokyo Institute of Technology, Tokyo, Japan
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8
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Nango E, Kumasaka T, Hirayama T, Tanaka N, Eguchi T. Structure of 2-deoxy-scyllo-inosose synthase, a key enzyme in the biosynthesis of 2-deoxystreptamine-containing aminoglycoside antibiotics, in complex with a mechanism-based inhibitor and NAD+. Proteins 2008; 70:517-27. [PMID: 17879343 DOI: 10.1002/prot.21526] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A key enzyme in the biosynthesis of clinically important aminoglycoside antibiotics is 2-deoxy-scyllo-inosose synthase (DOIS), which catalyzes carbocycle formation from D-glucose-6-phosphate to 2-deoxy-scyllo-inosose through a multistep reaction. This reaction mechanism is similar to the catalysis by dehydroquinate synthase (DHQS) of the cyclization of 3-deoxy-D-arabino-heputulosonate-7-phosphate to dehydroquinate in the shikimate pathway, but significant dissimilarity between these enzymes is also known, particularly in the stereochemistry of the phosphate elimination reaction and the cyclization. Here, the crystal structures of DOIS from Bacillus circulans and its complex with the substrate analog inhibitor carbaglucose-6-phosphate, NAD+, and Co2+ have been determined to provide structural insights into the reaction mechanism. The complex structure shows that an active site exists between the N-terminal and C-terminal domains and that the inhibitor coordinates a cobalt ion in this site. Two subunits exist as a dimer in the asymmetric unit. The two active sites of the dimer were observed to be different. One contains a dephosphorylated compound derived from the inhibitor and the other includes the inhibitor without change. The present study suggested that phosphate elimination proceeds through syn-elimination assisted by Glu 243 and the aldol condensation proceeds via a boat conformation. Also discussed are significant similarities and dissimilarities between DOIS and DHQS, particularly in terms of the structure at the active site and the reaction mechanism.
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Affiliation(s)
- Eriko Nango
- Department of Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8551, Japan
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9
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Rodríguez-Pérez T, Lavandera I, Fernández S, Sanghvi YS, Ferrero M, Gotor V. Novel and Efficient Chemoenzymatic Synthesis ofD-Glucose 6-Phosphate and Molecular Modeling Studies on the Selective Biocatalysis. European J Org Chem 2007. [DOI: 10.1002/ejoc.200700017] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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10
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Hirayama T, Kudo F, Huang Z, Eguchi T. Role of glutamate 243 in the active site of 2-deoxy-scyllo-inosose synthase from Bacillus circulans. Bioorg Med Chem 2007; 15:418-23. [PMID: 17035031 DOI: 10.1016/j.bmc.2006.09.042] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Revised: 09/19/2006] [Accepted: 09/21/2006] [Indexed: 11/18/2022]
Abstract
2-Deoxy-scyllo-inosose (DOI) synthase is involved in the biosynthesis of 2-deoxystreptamine-containing aminoglycoside antibiotics and catalyzes the carbocyclic formation from d-glucose-6-phosphate (G-6-P) into DOI. The reaction mechanism is proposed to be similar to that of dehydroquinate (DHQ) synthase in the shikimate pathway, and includes oxidation of C-4, beta-elimination of phosphate, reduction of C-4, ring opening, and intramolecular aldol cyclization. To investigate the reaction mechanism of DOI synthase, site-directed mutational analysis of three presumable catalytically important amino acids of DOI synthase derived from the butirosin producer Bacillus circulans (BtrC) was carried out. Steady state and pre-steady state kinetic analysis suggested that E243 of BtrC is catalytically involved in the phosphate elimination step. Further analysis of the mutant E243Q of BtrC using substrate analogue, glucose-6-phosphonate, clearly confirmed that E243 was responsible to abstract a proton at C-5 in G-6-P and set off phosphate elimination. This glutamate residue is completely conserved in all DOI synthases identified so far and the corresponding amino acid of DHQ synthase is completely conserved as asparagine. Therefore, this characteristic glutamate residue of DOI synthase is a key determinant to distinguish the reaction mechanism between DOI synthase and DHQ synthase as well as primary sequence.
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Affiliation(s)
- Toshifumi Hirayama
- Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
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11
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Hirayama T, Tamegai H, Kudo F, Kojima K, Kakinuma K, Eguchi T. Biosynthesis of 2-Deoxystreptamine-containing Antibiotics in Streptoalloteichus hindustanus JCM 3268: Characterization of 2-Deoxy-scyllo-inosose Synthase. J Antibiot (Tokyo) 2006; 59:358-61. [PMID: 16915821 DOI: 10.1038/ja.2006.51] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A part of the new biosynthetic gene cluster for 2-deoxystreptamine-containing antibiotics was identified from Streptoalloteichus hindustanus. The alloH gene in the gene cluster was deduced to encode 2-deoxy-scyllo-inosose synthase and the expressed protein AlloH was confirmed to have this enzyme activity. Furthermore, biochemical properties of AlloH were studied.
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Affiliation(s)
- Toshifumi Hirayama
- Department of Chemistry and Materials Science, Tokyo Institute of Technology, Japan
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12
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Serrano P, Llebaria A, Delgado A. Regio- and Stereoselective Synthesis of Aminoinositols and 1,2-Diaminoinositols from Conduritol B Epoxide. J Org Chem 2005; 70:7829-40. [PMID: 16277302 DOI: 10.1021/jo050521a] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[Chemical reaction: See text] A systematic approach to the regio- and stereoselective synthesis of aminoinositols and 1,2-diaminoinositols arising from tetra-O-benzylconduritol B epoxide (9) and its aziridine analogue 22, respectively, is described. In all cases, the synthetic methodologies rely on the regio- and stereocontrolled azidolysis of the starting precursors to give the corresponding trans regioadducts. Subsequent functional group manipulation under strict configurational control affords the isomeric cis adducts. Chemoselective functionalization of the diamine moiety in 1,2-diaminoinositol derivatives can be achieved by the proper design of the reaction sequence and choice of reagents. The described protocols allow efficient access to each of the eight possible configurations of the 1,2-diamino and 1,2-amino alcohol moieties from chemical modifications of the epoxide moiety on the common precursor 9.
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Affiliation(s)
- Pedro Serrano
- Unidad de Química Farmacéutica (Unidad Asociada al CSIC), Facultad de Farmacia, Universidad de Barcelona, Avda. Juan XXIII, s/n, 08028 Barcelona, Spain
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13
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Busscher GF, Rutjes FPJT, van Delft FL. 2-Deoxystreptamine: central scaffold of aminoglycoside antibiotics. Chem Rev 2005; 105:775-91. [PMID: 15755076 DOI: 10.1021/cr0404085] [Citation(s) in RCA: 119] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Guuske F Busscher
- IMM Organic Chemistry, Radboud University Nijmegen, Toernooiveld 1, 6525 ED Nijmegen, The Netherlands
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14
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Cox LR, DeBoos GA, Fullbrook JJ, Percy JM, Spencer N. Applying asymmetric dihydroxylation to the synthesis of difluorinated carbohydrate analogues: a 1,1-difluoro-1-deoxy-d-xylulose. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.tetasy.2004.11.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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15
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Crowley PJ, Fawcett J, Griffith GA, Moralee AC, Percy JM, Salafia V. Highly-functionalised difluorinated cyclohexane polyols via the Diels–Alder reaction: regiochemical control via the phenylsulfonyl group. Org Biomol Chem 2005; 3:3297-310. [PMID: 16132092 DOI: 10.1039/b507131c] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A difluorinated dienophile underwent cycloaddition reactions with a range of furans to afford cycloadducts which could be processed regio- and stereoselectively via episulfonium ions, generated by the reaction between their alkenyl groups and phenylsulfenyl chloride. The oxabicyclic products were oxidised to the phenylsulfonyl level and ring opened via E1(C)B or reductive desulfonative pathways to afford, ultimately, difluorinated cyclohexene or cyclohexane polyols.
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Affiliation(s)
- Patrick J Crowley
- Syngenta Ltd., Jealott's Hill International Research Centre, Bracknell, Berkshire, UK RG42 6EY
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16
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Huang Z, Kakinuma K, Eguchi T. Stereospecificity of hydride transfer in NAD+-catalyzed 2-deoxy-scyllo-inosose synthase, the key enzyme in the biosynthesis of 2-deoxystreptamine-containing aminocyclitol antibiotics. Bioorg Chem 2004; 33:82-9. [PMID: 15788164 DOI: 10.1016/j.bioorg.2004.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2004] [Revised: 09/21/2004] [Accepted: 09/21/2004] [Indexed: 12/01/2022]
Abstract
The key enzyme in the biosynthesis of clinically important aminocyclitol antibiotics is 2-deoxy-scyllo-inosose synthase (DOIS), which converts ubiquitous d-glucose 6-phosphate (G-6-P) into the specific carbocycle, 2-deoxy-scyllo-inosose with an aid of NAD(+)-NADH recycling. The NAD(+)-dependent first step of the DOIS reaction was examined in detail by the use of 6-phosphonate and 6-homophosphonate analogs of G-6-P. Both analogs showed competitive inhibition against the DOIS reaction with K(i) values of 1.3 and 2.8 mM, respectively, due to their inability for the subsequent phosphate elimination. Based on the direct spectrophotometric observation of NADH formed by the hydride transfer from 6-phosphonate to NAD(+), the stereospecificity of the hydride transfer in the DOIS reaction was analyzed with 6-[4-(2)H]phosphonate and was found to be pro-R specific.
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Affiliation(s)
- Zhen Huang
- Department of Chemistry and Materials Science, Tokyo Institute of Technology, O-okayama, Japan
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17
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Audouard C, Fawcett J, Griffith GA, Kérourédan E, Miah A, Percy JM, Yang H. A Potentially Divergent and Rapid Route to Analogues of Deoxycyclitols, Pentopyranoses, 6-Deoxyhexoses, and Hexoses. Org Lett 2004; 6:4269-72. [PMID: 15524460 DOI: 10.1021/ol0482902] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Direct precursors to analogues of pentopyranoses, 6-deoxyhexoses, and hexoses, in which a CF(2) center replaces the pyranose oxygen, have been synthesized rapidly from trifluoroethanol. A simple scaleable allylation reaction delivers ethers which undergo dehydrofluorination/metalation, followed by addition to either acrolein or cinnamaldehyde, to afford allylic alcohols. Fluorine-assisted [3,3]-rearrangement followed by reduction with sodium borohydride delivers diols, which undergo RCM smoothly to afford cyclohexene diols.
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Affiliation(s)
- Christophe Audouard
- Department of Chemistry, University of Leicester, University Road, Leicester LE1 7RH, UK
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18
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Kharel MK, Basnet DB, Lee HC, Liou K, Woo JS, Kim BG, Sohng JK. Isolation and characterization of the tobramycin biosynthetic gene cluster from Streptomyces tenebrarius. FEMS Microbiol Lett 2004; 230:185-90. [PMID: 14757238 DOI: 10.1016/s0378-1097(03)00881-4] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The biosynthetic gene cluster for tobramycin, a 2-deoxystreptamine-containing aminoglycoside antibiotic, was isolated from Streptomyces tenebrarius ATCC 17920. A genomic library of S. tenebrarius was constructed, and a cosmid, pST51, was isolated by the probes based on the core regions of 2-deoxy-scyllo-inosose (DOI) synthase, and L-glutamine:DOI aminotransferase and L-glutamine:scyllo-inosose aminotransferase. Sequencing of 33.9 kb revealed 24 open reading frames (ORFs) including putative tobramycin biosynthetic genes. We demonstrated that one of these ORFs, tbmA, encodes DOI synthase by in vitro enzyme assay of the purified protein. The catalytic residues of TbmA and dehydroquinate synthase were studied by homology modeling. The gene cluster found is likely to be involved in the biosynthesis of tobramycin.
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Affiliation(s)
- Madan Kumar Kharel
- Institute of Biomolecule Reconstruction, Sun Moon University, #100, Kalsan-ri, Tangjeong-myeon, Asansi, Chungnam 336-708, South Korea
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19
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Yamauchi N, Ueoka H, Kamada N, Murae T. Resemblance of Carbocycle Formation from Carbohydrates between Archaea and Eucarya/Eubacteria. Biosynthesis of Calditol, the Characteristic Lipid-Content Molecule inSulfolobus acidocaldarius. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2004. [DOI: 10.1246/bcsj.77.771] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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20
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Arany A, Crowley PJ, Fawcett J, Hursthouse MB, Kariuki BM, Light ME, Moralee AC, Percy JM, Salafia V. Highly-functionalised difluorinated (hydroxymethyl)conduritol analogues via the Diels-Alder reactions of a difluorinated dienophile. Org Biomol Chem 2004; 2:455-65. [PMID: 14770223 DOI: 10.1039/b314314g] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A difluorodienophile, synthesised using a Stille coupling reaction underwent tin(iv)-catalysed cycloaddition with three furans to afford oxa[2.2.1]bicycloheptenes in good yield. Reduction of ester and carbamate carbonyl groups and diol protection as the acetonide set the stage for palladium-catalysed hydrostannylation in two cases. Treatment of the stannanes with methyllithium triggered ring-opening to afford highly-functionalised difluorinated cyclohexenols which could be deprotected to afford (hydroxymethyl)conduritol analogues.
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Affiliation(s)
- Andrea Arany
- Department of Chemistry, University of Leicester, University Road, Leicester, UK
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21
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El Khadem HS, Fatiadi AJ. HYDRAZINE DERIVATIVES OF CARBA SUGARS AND RELATED COMPOUNDS. Adv Carbohydr Chem Biochem 2004; 59:135-73. [PMID: 15607765 DOI: 10.1016/s0065-2318(04)59004-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Hassan S El Khadem
- Department of Chemistry, The American University, Washington, DC 20016, USA
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22
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Nango E, Eguchi T, Kakinuma K. Active Site Mapping of 2-Deoxy-scyllo-inosose Synthase, the Key Starter Enzyme for the Biosynthesis of 2-Deoxystreptamine. Mechanism-Based Inhibition and Identification of Lysine-141 as the Entrapped Nucleophile. J Org Chem 2003; 69:593-600. [PMID: 14750780 DOI: 10.1021/jo034706y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A key enzyme in the biosynthesis of clinically important aminoglycoside antibiotics including neomycin, kanamycin, gentamicin, etc. is 2-deoxy-scyllo-inosose synthase (DOIS), which catalyzes the carbocycle formation from d-glucose-6-phosphate to 2-deoxy-scyllo-inosose (DOI). To clarify its precise reaction mechanism and crucial amino acid residues in the active site, we took advantage of a mechanism-based inhibitor carbaglucose-6-phosphate (pseudo-dl-glucose, C-6-P) with anticipation of its conversion to a reactive alpha,beta-unsaturated carbonyl intermediate. It turned out that C-6-P clearly showed time- and concentration-dependent inhibition against DOIS, and the molecular mass of the resulting modified-DOIS with C-6-P was 160 mass units larger than that of native DOIS. Thus, the expected alpha,beta-unsaturated intermediate appeared to trap a specific nucleophilic group in the active site through the Michael-type 1,4-addition. The covalently modified amino acid residue was determined to be Lys-141 by means of enzymatic digestion and subsequent LC/MS and LC/MS/MS of the digest. Also discussed are the role of Lys-141 in the substrate recognition and the reaction pathway and comparison with evolutionary related dehydroquinate synthase.
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Affiliation(s)
- Eriko Nango
- Department of Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8551, Japan
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23
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St Maurice M, Bearne SL, Lu W, Taylor SD. Inhibition of mandelate racemase by alpha-fluorobenzylphosphonates. Bioorg Med Chem Lett 2003; 13:2041-4. [PMID: 12781191 DOI: 10.1016/s0960-894x(03)00311-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Mandelate racemase catalyzes the interconversion of the enantiomers of mandelic acid. The enzyme binds the intermediate analogues (R)- and (S)-alpha-fluorobenzylphosphonate, and alpha,alpha-difluorobenzylphosphonate with 100-2500 times less affinity than it exhibits for (R,S)-alpha-hydroxybenzylphosphonate at pH 7.5. This apparent low affinity, relative to that of alpha-hydroxybenzylphosphonate, arises from the altered pKa values of the alpha-fluorobenzylphosphonates. For example, (S)-alpha-fluorobenzylphosphonate is bound with the same affinity as the substrate at pH 7.5, but this affinity is increased approximately 6-fold at pH 6.3.
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Affiliation(s)
- Martin St Maurice
- Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada B3H 1X5
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24
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Cox LR, DeBoos GA, Fullbrook JJ, Percy JM, Spencer NS, Tolley M. Catalytic asymmetric synthesis of a 1-deoxy-1,1-difluoro-D-xylulose. Org Lett 2003; 5:337-9. [PMID: 12556186 DOI: 10.1021/ol0273553] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] A new route, of potential strategic importance, to a difluorosugar analogue has been developed. Key steps included a Stille coupling and a highly regio- and enantioselective dihydroxylation of a highly substituted diene. Protecting groups were chosen to enhance the reactivity of the disubstituted allylic fragment in the AD reaction and allow deprotection under orthogonal conditions.
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Affiliation(s)
- Liam R Cox
- School of Chemical Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
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Crowley PJ, Fawcett J, Kariuki BM, Moralee AC, Percy JM, Salafia V. Basic and reductive sulfone-directed ring-opening reactions of difluorinated oxa[2.2.1]bicycloheptanes. Org Lett 2002; 4:4125-8. [PMID: 12423102 DOI: 10.1021/ol0268743] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phenylsulfenyl chloride reacts with racemic endo Diels-Alder adduct 4 (DEC = CONEt(2)) to afford lactone 8, which can be reduced and protected in a series of high-yielding steps. Key sulfone 10 can be ring opened under strong base conditions to afford vinyl sulfone 11. Attempted desulfonation resulted in the formation of a monofluoroalkene, but a direct desulfonation/eliminative ring opening with strain relief delivered highly functionalized monocyclic species 16. [reaction: see text]
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Affiliation(s)
- Patrick J Crowley
- Syngenta, Ltd., Jealott's Hill International Research Centre, Bracknell, Berks RG42 6ET, United Kingdom
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