1
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Liu SW, Zhai XX, Liu D, Liu YY, Sui LY, Luo KK, Yang Q, Li FN, Nikandrova AA, Imamutdinova AN, Lukianov DA, Osterman IA, Sergiev PV, Zhang BY, Zhang DJ, Xue CM, Sun CH. Bioprospecting of Actinobacterial Diversity and Antibacterial Secondary Metabolites from the Sediments of Four Saline Lakes on the Northern Tibetan Plateau. Microorganisms 2023; 11:2475. [PMID: 37894133 PMCID: PMC10609225 DOI: 10.3390/microorganisms11102475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 09/28/2023] [Accepted: 09/29/2023] [Indexed: 10/29/2023] Open
Abstract
The Tibetan Plateau, known as the "Roof of the World" and "The Third Pole", harbors numerous saline lakes primarily distributed in the Northern Tibetan Plateau. However, the challenging conditions of high altitude, low oxygen level, and harsh climate have limited investigations into the actinobacteria from these saline lakes. This study focuses on investigating the biodiversity and bioactive secondary metabolites of cultivable actinobacteria isolated from the sediments of four saline lakes on the Northern Tibetan Plateau. A total of 255 actinobacterial strains affiliated with 21 genera in 12 families of 7 orders were recovered by using the pure culture technique and 16S rRNA gene phylogenetic analysis. To facilitate a high-throughput bioactivity evaluation, 192 isolates underwent OSMAC cultivation in a miniaturized 24-well microbioreactor system (MATRIX cultivation). The antibacterial activity of crude extracts was then evaluated in a 96-well plate antibacterial assay. Forty-six strains demonstrated antagonistic effects against at least one tested pathogen, and their underlying antibacterial mechanisms were further investigated through a dual-fluorescent reporter assay (pDualrep2). Two Streptomyces strains (378 and 549) that produce compounds triggering DNA damage were prioritized for subsequent chemical investigations. Metabolomics profiling involving HPLC-UV/vis, UPLC-QTOF-MS/MS, and molecular networking identified three types of bioactive metabolites belonging to the aromatic polyketide family, i.e., cosmomycin, kidamycin, and hedamycin. In-depth analysis of the metabolomic data unveiled some potentially novel anthracycline compounds. A genome mining study based on the whole-genome sequences of strains 378 and 549 identified gene clusters potentially responsible for cosmomycin and kidamycin biosynthesis. This work highlights the effectiveness of combining metabolomic and genomic approaches to rapidly identify bioactive chemicals within microbial extracts. The saline lakes on the Northern Tibetan Plateau present prospective sources for discovering novel actinobacteria and biologically active compounds.
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Affiliation(s)
- Shao-Wei Liu
- Department of Microbial Chemistry, Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100050, China; (S.-W.L.)
| | - Xiao-Xu Zhai
- Department of Microbial Chemistry, Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100050, China; (S.-W.L.)
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining 810016, China
- College of Life Sciences, Jiamusi University, Jiamusi 154000, China
| | - Di Liu
- Department of Microbial Chemistry, Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100050, China; (S.-W.L.)
- College of Life Sciences, Jiamusi University, Jiamusi 154000, China
| | - Yu-Yu Liu
- Department of Microbial Chemistry, Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100050, China; (S.-W.L.)
| | - Li-Ying Sui
- College of Marine and Environmental Sciences, Tianjin University of Science and Technology, Tianjin 300457, China
| | - Ke-Ke Luo
- Department of Microbial Chemistry, Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100050, China; (S.-W.L.)
| | - Qin Yang
- Department of Microbial Chemistry, Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100050, China; (S.-W.L.)
| | - Fei-Na Li
- Laboratory of Respiratory Diseases, Beijing Key Laboratory of Pediatric Respiratory Infection Diseases, Beijing Pediatric Research Institute, Beijing Children’s Hospital, Capital Medical University, Key Laboratory of Major Diseases in Children, Ministry of Education, National Clinical Research Center for Respiratory Diseases, National Center for Children’s Health, Beijing 100045, China;
| | - Arina A. Nikandrova
- Center of Life Sciences, Skolkovo Institute of Science and Technology, 121205 Moscow, Russia
- Department of Biology, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Arina N. Imamutdinova
- Center of Life Sciences, Skolkovo Institute of Science and Technology, 121205 Moscow, Russia
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Dmitrii A. Lukianov
- Center of Life Sciences, Skolkovo Institute of Science and Technology, 121205 Moscow, Russia
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Ilya A. Osterman
- Center of Life Sciences, Skolkovo Institute of Science and Technology, 121205 Moscow, Russia
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Petr V. Sergiev
- Center of Life Sciences, Skolkovo Institute of Science and Technology, 121205 Moscow, Russia
- Department of Chemistry, Lomonosov Moscow State University, 119991 Moscow, Russia
| | - Ben-Yin Zhang
- College of Eco-Environmental Engineering, Qinghai University, Xining 810016, China; (B.-Y.Z.); (D.-J.Z.)
| | - De-Jun Zhang
- College of Eco-Environmental Engineering, Qinghai University, Xining 810016, China; (B.-Y.Z.); (D.-J.Z.)
| | - Chun-Mei Xue
- College of Life Sciences, Jiamusi University, Jiamusi 154000, China
| | - Cheng-Hang Sun
- Department of Microbial Chemistry, Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100050, China; (S.-W.L.)
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining 810016, China
- College of Eco-Environmental Engineering, Qinghai University, Xining 810016, China; (B.-Y.Z.); (D.-J.Z.)
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2
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Heo KT, Lee B, Jang JH, Hong YS. Elucidation of the di-c-glycosylation steps during biosynthesis of the antitumor antibiotic, kidamycin. Front Bioeng Biotechnol 2022; 10:985696. [PMID: 36091425 PMCID: PMC9452638 DOI: 10.3389/fbioe.2022.985696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 07/21/2022] [Indexed: 11/24/2022] Open
Abstract
Kidamycins belong to the pluramycin family of antitumor antibiotics that contain di-C-glycosylated angucycline. Owing to its interesting biological activity, several synthetic derivatives of kidamycins are currently being developed. However, the synthesis of these complex structural compounds with unusual C-glycosylated residues is difficult. In the kidamycin-producing Streptomyces sp. W2061 strain, the genes encoding the biosynthetic enzymes responsible for the structural features of kidamycin were identified. Two glycosyltransferase-coding genes, kid7 and kid21, were found in the kidamycin biosynthetic gene cluster (BGC). Gene inactivation studies revealed that the subsequent glycosylation steps occurred in a sequential manner, in which Kid7 first attached N,N-dimethylvancosamine to the C10 position of angucycline aglycone, following which Kid21 transferred an anglosamine moiety to C8 of the C10-glycosylated angucycline. Therefore, this is the first report to reveal the sequential biosynthetic steps of the unique C-glycosylated amino-deoxyhexoses of kidamycin. Additionally, we confirmed that all three methyltransferases (Kid4, Kid9, and Kid24) present in this BGC were involved in the biosynthesis of these amino-deoxyhexoses, N,N-dimethylvancosamine and anglosamine. Aglycone compounds and the mono-C-glycosylated compound obtained in this process will be used as substrates for the development of synthetic derivatives in the future.
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Affiliation(s)
- Kyung Taek Heo
- Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungbuk, South Korea
- Department of Bio-Molecular Science, KRIBB School of Bioscience, University of Science and Technology(UST), Daejeon, South Korea
| | - Byeongsan Lee
- Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungbuk, South Korea
| | - Jae-Hyuk Jang
- Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungbuk, South Korea
- Department of Bio-Molecular Science, KRIBB School of Bioscience, University of Science and Technology(UST), Daejeon, South Korea
- *Correspondence: Jae-Hyuk Jang, ; Young-Soo Hong,
| | - Young-Soo Hong
- Chemical Biology Research Center, Korea Research Institute of Bioscience and Biotechnology, Chungbuk, South Korea
- Department of Bio-Molecular Science, KRIBB School of Bioscience, University of Science and Technology(UST), Daejeon, South Korea
- *Correspondence: Jae-Hyuk Jang, ; Young-Soo Hong,
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3
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Bradley NP, Wahl KL, Steenwyk JL, Rokas A, Eichman BF. Resistance-Guided Mining of Bacterial Genotoxins Defines a Family of DNA Glycosylases. mBio 2022; 13:e0329721. [PMID: 35311535 PMCID: PMC9040887 DOI: 10.1128/mbio.03297-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 02/22/2022] [Indexed: 11/20/2022] Open
Abstract
Unique DNA repair enzymes that provide self-resistance against therapeutically important, genotoxic natural products have been discovered in bacterial biosynthetic gene clusters (BGCs). Among these, the DNA glycosylase AlkZ is essential for azinomycin B production and belongs to the HTH_42 superfamily of uncharacterized proteins. Despite their widespread existence in antibiotic producers and pathogens, the roles of these proteins in production of other natural products are unknown. Here, we determine the evolutionary relationship and genomic distribution of all HTH_42 proteins from Streptomyces and use a resistance-based genome mining approach to identify homologs associated with known and uncharacterized BGCs. We find that AlkZ-like (AZL) proteins constitute one distinct HTH_42 subfamily and are highly enriched in BGCs and variable in sequence, suggesting each has evolved to protect against a specific secondary metabolite. As a validation of the approach, we show that the AZL protein, HedH4, associated with biosynthesis of the alkylating agent hedamycin, excises hedamycin-DNA adducts with exquisite specificity and provides resistance to the natural product in cells. We also identify a second, phylogenetically and functionally distinct subfamily whose proteins are never associated with BGCs, are highly conserved with respect to sequence and genomic neighborhood, and repair DNA lesions not associated with a particular natural product. This work delineates two related families of DNA repair enzymes-one specific for complex alkyl-DNA lesions and involved in self-resistance to antimicrobials and the other likely involved in protection against an array of genotoxins-and provides a framework for targeted discovery of new genotoxic compounds with therapeutic potential. IMPORTANCE Bacteria are rich sources of secondary metabolites that include DNA-damaging genotoxins with antitumor/antibiotic properties. Although Streptomyces produce a diverse number of therapeutic genotoxins, efforts toward targeted discovery of biosynthetic gene clusters (BGCs) producing DNA-damaging agents is lacking. Moreover, work on toxin-resistance genes has lagged behind our understanding of those involved in natural product synthesis. Here, we identified over 70 uncharacterized BGCs producing potentially novel genotoxins through resistance-based genome mining using the azinomycin B-resistance DNA glycosylase AlkZ. We validate our analysis by characterizing the enzymatic activity and cellular resistance of one AlkZ ortholog in the BGC of hedamycin, a potent DNA alkylating agent. Moreover, we uncover a second, phylogenetically distinct family of proteins related to Escherichia coli YcaQ, a DNA glycosylase capable of unhooking interstrand DNA cross-links, which differs from the AlkZ-like family in sequence, genomic location, proximity to BGCs, and substrate specificity. This work defines two families of DNA glycosylase for specialized repair of complex genotoxic natural products and generalized repair of a broad range of alkyl-DNA adducts and provides a framework for targeted discovery of new compounds with therapeutic potential.
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Affiliation(s)
- Noah P. Bradley
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Katherine L. Wahl
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Jacob L. Steenwyk
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
| | - Antonis Rokas
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Brandt F. Eichman
- Department of Biological Sciences, Vanderbilt University, Nashville, Tennessee, USA
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
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4
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Ribaudo G, Ongaro A, Zorzan M, Pezzani R, Redaelli M, Zagotto G, Memo M, Gianoncelli A. Investigation of the molecular reactivity of bioactive oxiranylmethyloxy anthraquinones. Arch Pharm (Weinheim) 2019; 352:e1900030. [DOI: 10.1002/ardp.201900030] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 03/22/2019] [Accepted: 03/25/2019] [Indexed: 01/09/2023]
Affiliation(s)
- Giovanni Ribaudo
- Department of Pharmaceutical and Pharmacological SciencesUniversity of PadovaPadova Italy
| | - Alberto Ongaro
- Department of Molecular and Translational MedicineUniversity of BresciaBrescia Italy
| | - Maira Zorzan
- Department of Molecular Medicine (DMM)University of PadovaPadova Italy
| | | | - Marco Redaelli
- Department of Pharmaceutical and Pharmacological SciencesUniversity of PadovaPadova Italy
| | - Giuseppe Zagotto
- Department of Pharmaceutical and Pharmacological SciencesUniversity of PadovaPadova Italy
| | - Maurizio Memo
- Department of Molecular and Translational MedicineUniversity of BresciaBrescia Italy
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5
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Lambert M, Jambon S, Depauw S, David-Cordonnier MH. Targeting Transcription Factors for Cancer Treatment. Molecules 2018; 23:molecules23061479. [PMID: 29921764 PMCID: PMC6100431 DOI: 10.3390/molecules23061479] [Citation(s) in RCA: 229] [Impact Index Per Article: 38.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 06/11/2018] [Accepted: 06/15/2018] [Indexed: 12/15/2022] Open
Abstract
Transcription factors are involved in a large number of human diseases such as cancers for which they account for about 20% of all oncogenes identified so far. For long time, with the exception of ligand-inducible nuclear receptors, transcription factors were considered as “undruggable” targets. Advances knowledge of these transcription factors, in terms of structure, function (expression, degradation, interaction with co-factors and other proteins) and the dynamics of their mode of binding to DNA has changed this postulate and paved the way for new therapies targeted against transcription factors. Here, we discuss various ways to target transcription factors in cancer models: by modulating their expression or degradation, by blocking protein/protein interactions, by targeting the transcription factor itself to prevent its DNA binding either through a binding pocket or at the DNA-interacting site, some of these inhibitors being currently used or evaluated for cancer treatment. Such different targeting of transcription factors by small molecules is facilitated by modern chemistry developing a wide variety of original molecules designed to specifically abort transcription factor and by an increased knowledge of their pathological implication through the use of new technologies in order to make it possible to improve therapeutic control of transcription factor oncogenic functions.
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Affiliation(s)
- Mélanie Lambert
- INSERM UMR-S1172-JPARC (Jean-Pierre Aubert Research Center), Lille University and Hospital Center (CHU-Lille), Institut pour la Recherche sur le Cancer de Lille (IRCL), Place de Verdun, F-59045 Lille, France.
| | - Samy Jambon
- INSERM UMR-S1172-JPARC (Jean-Pierre Aubert Research Center), Lille University and Hospital Center (CHU-Lille), Institut pour la Recherche sur le Cancer de Lille (IRCL), Place de Verdun, F-59045 Lille, France.
| | - Sabine Depauw
- INSERM UMR-S1172-JPARC (Jean-Pierre Aubert Research Center), Lille University and Hospital Center (CHU-Lille), Institut pour la Recherche sur le Cancer de Lille (IRCL), Place de Verdun, F-59045 Lille, France.
| | - Marie-Hélène David-Cordonnier
- INSERM UMR-S1172-JPARC (Jean-Pierre Aubert Research Center), Lille University and Hospital Center (CHU-Lille), Institut pour la Recherche sur le Cancer de Lille (IRCL), Place de Verdun, F-59045 Lille, France.
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6
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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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7
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Cañeque T, Gomes F, Mai TT, Maestri G, Malacria M, Rodriguez R. Synthesis of marmycin A and investigation into its cellular activity. Nat Chem 2015; 7:744-51. [PMID: 26291947 PMCID: PMC5892709 DOI: 10.1038/nchem.2302] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 06/10/2015] [Indexed: 12/29/2022]
Abstract
Anthracyclines such as doxorubicin are used extensively in the treatment of cancers. Anthraquinone-related angucyclines also exhibit antiproliferative properties and have been proposed to operate via similar mechanisms, including direct genome targeting. Here, we report the chemical synthesis of marmycin A and the study of its cellular activity. The aromatic core was constructed by means of a one-pot multistep reaction comprising a regioselective Diels-Alder cycloaddition, and the complex sugar backbone was introduced through a copper-catalysed Ullmann cross-coupling, followed by a challenging Friedel-Crafts cyclization. Remarkably, fluorescence microscopy revealed that marmycin A does not target the nucleus but instead accumulates in lysosomes, thereby promoting cell death independently of genome targeting. Furthermore, a synthetic dimer of marmycin A and the lysosome-targeting agent artesunate exhibited a synergistic activity against the invasive MDA-MB-231 cancer cell line. These findings shed light on the elusive pathways through which anthraquinone derivatives act in cells, pointing towards unanticipated biological and therapeutic applications.
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Affiliation(s)
- Tatiana Cañeque
- Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles du CNRS, 1 Avenue de la Terrasse, Gif sur-Yvette 91198, France
| | - Filipe Gomes
- Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles du CNRS, 1 Avenue de la Terrasse, Gif sur-Yvette 91198, France
| | - Trang Thi Mai
- Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles du CNRS, 1 Avenue de la Terrasse, Gif sur-Yvette 91198, France
| | - Giovanni Maestri
- Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles du CNRS, 1 Avenue de la Terrasse, Gif sur-Yvette 91198, France
- Department of Chemistry, Università degli Studi di Parma, Parco Area delle Scienze 17/a, Parma 43124, Italy
| | - Max Malacria
- Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles du CNRS, 1 Avenue de la Terrasse, Gif sur-Yvette 91198, France
- Institut Parisien de Chimie Moléculaire, Sorbonne Universités, UPMC Univ Paris 06, UMR CNRS 8232, Paris CEDEX 05 75252, France
| | - Raphaël Rodriguez
- Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles du CNRS, 1 Avenue de la Terrasse, Gif sur-Yvette 91198, France
- Institut Curie Research Center, Organic Synthesis and Cell Biology Group, 26 rue d’Ulm, Paris Cedex 05 75248, France
- CNRS UMR 3666, Paris 75005, France
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8
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Jones KD, Rixson JE, Skelton BW, Gericke KM, Stewart SG. The Total Synthesis of Heraclemycin B through β-Ketosulfoxide and Aldehyde Annulation. ASIAN J ORG CHEM 2015. [DOI: 10.1002/ajoc.201500184] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Kieran D. Jones
- School of Chemistry and Biochemistry; The University of Western Australia (M310); 35 Stirling Highway Crawley WA 6009 (Australia)
| | - James E. Rixson
- School of Chemistry and Biochemistry; The University of Western Australia (M310); 35 Stirling Highway Crawley WA 6009 (Australia)
| | - Brian W. Skelton
- Centre for Microscopy, Characterisation and Analysis; The University of Western Australia; Crawley WA 6009 Australia
| | | | - Scott G. Stewart
- School of Chemistry and Biochemistry; The University of Western Australia (M310); 35 Stirling Highway Crawley WA 6009 (Australia)
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9
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Cai X, Ng K, Panesar H, Moon SJ, Paredes M, Ishida K, Hertweck C, Minehan TG. Total synthesis of the antitumor natural product polycarcin V and evaluation of its DNA binding profile. Org Lett 2014; 16:2962-5. [PMID: 24824354 PMCID: PMC4059221 DOI: 10.1021/ol501095w] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Indexed: 12/03/2022]
Abstract
The convergent total synthesis of polycarcin V, a gilvocarcin-type natural product that shows significant cytotoxicity with selectivity for nonsmall-cell lung cancer, breast cancer, and melanoma cells, has been achieved in 13 steps from 7, 8, and 22; the sequence features a stereoselective α-C-glycosylation reaction for the union of protected carbohydrate 7 and naphthol 8. The association constant for the binding of polycarcin V to duplex DNA is similar to that previously reported for gilvocarcin V.
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Affiliation(s)
- Xiao Cai
- Department
of Chemistry and Biochemistry, California
State University, Northridge, 18111 Nordhoff Street, Northridge, California 91330, United States
| | - Kevin Ng
- Department
of Chemistry and Biochemistry, California
State University, Northridge, 18111 Nordhoff Street, Northridge, California 91330, United States
| | - Harmanpreet Panesar
- Department
of Chemistry and Biochemistry, California
State University, Northridge, 18111 Nordhoff Street, Northridge, California 91330, United States
| | - Seong-Jin Moon
- Department
of Chemistry and Biochemistry, California
State University, Northridge, 18111 Nordhoff Street, Northridge, California 91330, United States
| | - Maria Paredes
- Department
of Chemistry and Biochemistry, California
State University, Northridge, 18111 Nordhoff Street, Northridge, California 91330, United States
| | - Keishi Ishida
- Department
of Biomolecular Chemistry, Leibniz Institute
for Natural Product Research and Infection Biology, HKI Beutenbergstrasse 11a, 07745 Jena, Germany
| | - Christian Hertweck
- Department
of Biomolecular Chemistry, Leibniz Institute
for Natural Product Research and Infection Biology, HKI Beutenbergstrasse 11a, 07745 Jena, Germany
| | - Thomas G. Minehan
- Department
of Chemistry and Biochemistry, California
State University, Northridge, 18111 Nordhoff Street, Northridge, California 91330, United States
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10
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Mavlan M, Ng K, Panesar H, Yepremyan A, Minehan TG. Synthesis of 3,3'-di-O-methyl ardimerin and exploration of its DNA binding properties. Org Lett 2014; 16:2212-5. [PMID: 24712737 PMCID: PMC4067242 DOI: 10.1021/ol500725e] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
![]()
The
3,3′-di-O-methyl derivative (15) of the bis-C-aryl glycoside natural product
ardimerin (1) has been synthesized in 11 steps from 2,3,4,6-tetrabenzylglucose
(2) and 1,2,3-trimethoxybenzene (3). Key
steps in the synthesis involve a Lewis acid mediated Friedel–Crafts
type glycosylation and a Yamaguchi lactonization under Yonemitsu conditions.
3,3′-Di-O-methyl ardimerin aggregates in aqueous
solutions at concentrations greater than 1 μM, and both UV and
fluorescence binding studies indicate that 15 has a low
affinity for duplex DNA.
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Affiliation(s)
- Miran Mavlan
- Department of Chemistry and Biochemistry, California State University , Northridge 18111 Nordhoff Street, Northridge, California 91330, United States
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11
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Rational approaches, design strategies, structure activity relationship and mechanistic insights for anticancer hybrids. Eur J Med Chem 2014; 77:422-87. [PMID: 24685980 DOI: 10.1016/j.ejmech.2014.03.018] [Citation(s) in RCA: 306] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2013] [Revised: 03/02/2014] [Accepted: 03/06/2014] [Indexed: 12/16/2022]
Abstract
A Hybrid drug which comprises the incorporation of two drug pharmacophores in one single molecule are basically designed to interact with multiple targets or to amplify its effect through action on another bio target as one single molecule or to counterbalance the known side effects associated with the other hybrid part(.) The present review article offers a detailed account of the design strategies employed for the synthesis of anticancer agents via molecular hybridization techniques. Over the years, the researchers have employed this technique to discover some promising chemical architectures displaying significant anticancer profiles. Molecular hybridization as a tool has been particularly utilized for targeting tubulin protein as exemplified through the number of research papers. The microtubule inhibitors such as taxol, colchicine, chalcones, combretasatin, phenstatins and vinca alkaloids have been utilized as one of the functionality of the hybrids and promising results have been obtained in most of the cases with some of the tubulin based hybrids exhibiting anticancer activity at nanomolar level. Linkage with steroids as biological carrier vector for anticancer drugs and the inclusion of pyrrolo [2,1-c] [1,4]benzodiazepines (PBDs), a family of DNA interactive antitumor antibiotics derived from Streptomyces species in hybrid structure based drug design has also emerged as a potential strategy. Various heteroaryl based hybrids in particular isatin and coumarins have also been designed and reported to posses' remarkable inhibitory potential. Apart from presenting the design strategies, the article also highlights the structure activity relationship along with mechanistic insights revealed during the biological evaluation of the hybrids.
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12
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Silvestri C, Brodbelt JS. Tandem mass spectrometry for characterization of covalent adducts of DNA with anticancer therapeutics. MASS SPECTROMETRY REVIEWS 2013; 32:247-66. [PMID: 23150278 PMCID: PMC3578003 DOI: 10.1002/mas.21363] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 08/17/2012] [Accepted: 08/18/2012] [Indexed: 05/17/2023]
Abstract
The chemotherapeutic activities of many anticancer and antibacterial drugs arise from their interactions with nucleic acid substrates. Some of these ligands interact with DNA in a way that causes conformational changes or damage to the nucleic acid targets, ultimately altering recognition by key DNA-specific enzymes, interfering with DNA transcription or prohibiting replication, and terminating cell growth and proliferation. The design and synthesis of ligands that bind to nucleic acids remains a dynamic field in medicinal chemistry and pharmaceutical research. The quest for more selective and efficacious DNA-interactive anticancer chemotherapeutics has likewise catalyzed the need for sensitive analytical methods that can provide structural information about the nature of the resulting DNA adducts and provide insight into the mechanistic pathways of the DNA/drug interactions and the impact on the cellular processes in biological systems. This review focuses on the array of tandem mass spectrometric strategies developed and applied for characterization of covalent adducts formed between DNA and anticancer ligands.
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Affiliation(s)
- Catherine Silvestri
- Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX 78712, USA
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Javidpour P, Das A, Khosla C, Tsai SC. Structural and biochemical studies of the hedamycin type II polyketide ketoreductase (HedKR): molecular basis of stereo- and regiospecificities. Biochemistry 2011; 50:7426-39. [PMID: 21776967 DOI: 10.1021/bi2006866] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Bacterial aromatic polyketides that include many antibiotic and antitumor therapeutics are biosynthesized by the type II polyketide synthase (PKS), which consists of 5-10 stand-alone enzymatic domains. Hedamycin, an antitumor antibiotic polyketide, is uniquely primed with a hexadienyl group generated by a type I PKS followed by coupling to a downstream type II PKS to biosynthesize a 24-carbon polyketide, whose C9 position is reduced by hedamycin type II ketoreductase (hedKR). HedKR is homologous to the actinorhodin KR (actKR), for which we have conducted extensive structural studies previously. How hedKR can accommodate a longer polyketide substrate than the actKR, and the molecular basis of its regio- and stereospecificities, is not well understood. Here we present a detailed study of hedKR that sheds light on its specificity. Sequence alignment of KRs predicts that hedKR is less active than actKR, with significant differences in substrate/inhibitor recognition. In vitro and in vivo assays of hedKR confirmed this hypothesis. The hedKR crystal structure further provides the molecular basis for the observed differences between hedKR and actKR in the recognition of substrates and inhibitors. Instead of the 94-PGG-96 motif observed in actKR, hedKR has the 92-NGG-94 motif, leading to S-dominant stereospecificity, whose molecular basis can be explained by the crystal structure. Together with mutations, assay results, docking simulations, and the hedKR crystal structure, a model for the observed regio- and stereospecificities is presented herein that elucidates how different type II KRs recognize substrates with different chain lengths, yet precisely reduce only the C9-carbonyl group. The molecular features of hedKR important for regio- and stereospecificities can potentially be applied to biosynthesize new polyketides via protein engineering that rationally controls polyketide ketoreduction.
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Affiliation(s)
- Pouya Javidpour
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, California 92697, United States
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14
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Das A, Khosla C. In vivo and in vitro analysis of the hedamycin polyketide synthase. ACTA ACUST UNITED AC 2010; 16:1197-207. [PMID: 19942143 DOI: 10.1016/j.chembiol.2009.11.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2009] [Revised: 10/19/2009] [Accepted: 11/02/2009] [Indexed: 11/25/2022]
Abstract
Hedamycin is an antitumor polyketide antibiotic with unusual biosynthetic features. Earlier sequence analysis of the hedamycin biosynthetic gene cluster implied a role for type I and type II polyketide synthases (PKSs). We demonstrate that the hedamycin minimal PKS can synthesize a dodecaketide backbone. The ketosynthase (KS) subunit of this PKS has specificity for both type I and type II acyl carrier proteins (ACPs) with which it collaborates during chain initiation and chain elongation, respectively. The KS receives a C(6) primer unit from the terminal ACP domain of HedU (a type I PKS protein) directly and subsequently interacts with the ACP domain of HedE (a type II PKS protein) during the process of chain elongation. HedE is a bifunctional protein with both ACP and aromatase activity. Its aromatase domain can modulate the chain length specificity of the minimal PKS. Chain length can also be influenced by HedA, the C-9 ketoreductase. While co-expression of the hedamycin minimal PKS and a chain-initiation module from the R1128 PKS yields an isobutyryl-primed decaketide, the orthologous PKS subunits from the hedamycin gene cluster itself are unable to prime the minimal PKS with a nonacetyl starter unit. Our findings provide new insights into the mechanism of chain initiation and elongation by type II PKSs.
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Affiliation(s)
- Abhirup Das
- Department of Chemistry, Stanford University, CA 94305-5025, USA
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15
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Murphy BT, Narender T, Kauffman CA, Woolery M, Jensen PR, Fenical W. Saliniquinones A-F, New Members of the Highly Cytotoxic Anthraquinone-γ-Pyrones from the Marine Actinomycete Salinispora arenicola.. Aust J Chem 2010; 63. [PMID: 24223427 DOI: 10.1071/ch10068] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Six new anthraquinone-γ-pyrones, saliniquinones A-F (1-6), which are related to metabolites of the pluramycin/altromycin class, were isolated from a fermentation broth of the marine actinomycete Salinispora arenicola (strain CNS-325). Their structures were determined by analysis of one- and two-dimensional NMR spectroscopic and high-resolution mass spectrometric data. The relative and absolute configurations of compounds 1-6 were determined by analysis of NOESY NMR spectroscopic data and by comparison of circular dichroism and optical rotation data with model compounds found in the literature. Saliniquinone A (1) exhibited potent inhibition of the human colon adenocarcinoma cell line (HCT-116) with an IC50 of 9.9 × 10-9 M. In the context of the biosynthetic diversity of S. arenicola, compounds 1-6 represent secondary metabolites that appear to be strain specific and thus occur outside of the core group of compounds commonly observed from this species.
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Affiliation(s)
- Brian T Murphy
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California-San Diego, La Jolla, CA 92093-0204, USA
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16
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Wróblewski AE, Szewczyk EM, Baôk-Sypień II. Synthesis of (1R,2R)- and (1S,2R)-1,2-Epoxy-3-hydroxypropylphosphonates as Analogues of Fosfomycin. Arch Pharm (Weinheim) 2009; 342:521-7. [DOI: 10.1002/ardp.200900044] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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17
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Wright BJD, Hartung J, Peng F, Van de Water R, Liu H, Tan QH, Chou TC, Danishefsky SJ. Synthesis of pluraflavin A "aglycone". J Am Chem Soc 2009; 130:16786-90. [PMID: 19049469 DOI: 10.1021/ja805936v] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The "aglycone" of pluraflavin A (2) has been synthesized. The key features of this synthesis include a 1,3-dipolar cycloaddition between a nitrile oxide (cf. 14) and an olefin (22) to yield an isoxazoline followed by subsequent conversion into the gamma-pyrone of pluraflavin A. The epoxide moiety linked to the pyrone is installed prior to Diels-Alder installation of the D ring, which allows access to a number of potentially active cytotoxic intermediates en route to the final compound. The preliminary in vitro results of two such compounds are also included with the racemic title compound exhibiting cytotoxicity in the nanomolar range.
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Affiliation(s)
- Benjamin J D Wright
- Department of Chemistry, Columbia University, Havemeyer Hall, 3000 Broadway, New York, New York 10027, USA
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Pfoh R, Laatsch H, Sheldrick GM. Crystal structure of trioxacarcin A covalently bound to DNA. Nucleic Acids Res 2008; 36:3508-14. [PMID: 18453630 PMCID: PMC2425490 DOI: 10.1093/nar/gkn245] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
We report a crystal structure that shows an antibiotic that extracts a nucleobase from a DNA molecule ‘caught in the act’ after forming a covalent bond but before departing with the base. The structure of trioxacarcin A covalently bound to double-stranded d(AACCGGTT) was determined to 1.78 Å resolution by MAD phasing employing brominated oligonucleotides. The DNA–drug complex has a unique structure that combines alkylation (at the N7 position of a guanine), intercalation (on the 3′-side of the alkylated guanine), and base flip-out. An antibiotic-induced flipping-out of a single, nonterminal nucleobase from a DNA duplex was observed for the first time in a crystal structure.
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Affiliation(s)
- Roland Pfoh
- Lehrstuhl für Strukturchemie, Georg-August-Universität, Tammannstr. 4, 37077 Göttingen, Germany
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19
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Dziegielewska B, Beerman TA, Bianco PR. Inhibition of RecBCD enzyme by antineoplastic DNA alkylating agents. J Mol Biol 2006; 361:898-919. [PMID: 16887143 DOI: 10.1016/j.jmb.2006.06.068] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Revised: 06/26/2006] [Accepted: 06/28/2006] [Indexed: 01/09/2023]
Abstract
To understand how bulky adducts might perturb DNA helicase function, three distinct DNA-binding agents were used to determine the effects of DNA alkylation on a DNA helicase. Adozelesin, ecteinascidin 743 (Et743) and hedamycin each possess unique structures and sequence selectivity. They bind to double-stranded DNA and alkylate one strand of the duplex in cis, adding adducts that alter the structure of DNA significantly. The results show that Et743 was the most potent inhibitor of DNA unwinding, followed by adozelesin and hedamycin. Et743 significantly inhibited unwinding, enhanced degradation of DNA, and completely eliminated the ability of the translocating RecBCD enzyme to recognize and respond to the recombination hotspot chi. Unwinding of adozelesin-modified DNA was accompanied by the appearance of unwinding intermediates, consistent with enzyme entrapment or stalling. Further, adozelesin also induced "apparent" chi fragment formation. The combination of enzyme sequestering and pseudo-chi modification of RecBCD, results in biphasic time-courses of DNA unwinding. Hedamycin also reduced RecBCD activity, albeit at increased concentrations of drug relative to either adozelesin or Et743. Remarkably, the hedamycin modification resulted in constitutive activation of the bottom-strand nuclease activity of the enzyme, while leaving the ability of the translocating enzyme to recognize and respond to chi largely intact. Finally, the results show that DNA alkylation does not significantly perturb the allosteric interaction that activates the enzyme for ATP hydrolysis, as the efficiency of ATP utilization for DNA unwinding is affected only marginally. These results taken together present a unique response of RecBCD enzyme to bulky DNA adducts. We correlate these effects with the recently determined crystal structure of the RecBCD holoenzyme bound to DNA.
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Affiliation(s)
- Barbara Dziegielewska
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
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20
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Guddneppanavar R, Saluta G, Kucera GL, Bierbach U. Synthesis, biological activity, and DNA-damage profile of platinum-threading intercalator conjugates designed to target adenine. J Med Chem 2006; 49:3204-14. [PMID: 16722638 DOI: 10.1021/jm060035v] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
PT-ACRAMTU {[PtCl(en)(ACRAMTU)](NO3)2, 2; ACRAMTU = 1-[2-(acridin-9-ylamino)ethyl]-1,3-dimethylthiourea, 1, en = ethane-1,2-diamine} is the prototype of a series of DNA-targeted adenine-affinic dual intercalating/platinating agents. Several novel 4,9-disubstituted acridines and the corresponding platinum-acridine conjugates were synthesized. The newly introduced 4-carboxamide side chains contain H-bond donor/acceptor functions designed to promote groove- and sequence-specific platinum binding. In HL-60 (leukemia) and H460 (lung) cancer cells, IC50 values in the micromolar to millimolar range were observed. Several of the intercalators show enhanced cytotoxicity compared to prototype 1, but conjugate 2 appears to be the most potent hybrid agent. Enzymatic digestion assays in conjunction with liquid chromatography-electrospray mass spectrometry analysis indicate that the new conjugates produce PT-ACRAMTU-type DNA damage. Platinum-modified 2'-deoxyguanosine, dG, and several dinucleotide fragments, d(NpN)*, were detected. One of the conjugates showed significantly higher levels of binding to A-containing sites than conjugate 2 (35 +/- 3% vs 24 +/- 3%). Possible structure-activity relationships are discussed.
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Affiliation(s)
- Mark Lukin
- Department of Pharmacological Sciences, State University of New York at Stony Brook, School of Medicine, 11794-8651, USA
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22
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Abstract
Tungsten-catalyzed cycloisomerization of alkynyl alcohols including 8 provides only the endocyclic enol ether (11) as a key intermediate for the branched C-glycoside substructure (2) of altromycin B. A sequence of Stille cross-coupling reaction and regio- and stereoselective functional group transformations affords each C13-diastereomer of the branched C-arylglycoside (2a and 2b). [reaction: see text]
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Affiliation(s)
- Bonsuk Koo
- Department of Chemistry, Emory University, Atlanta, GA 30322, USA
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Tu LC, Matsui SI, Beerman TA. Hedamycin, a DNA alkylator, induces γH2AX and chromosome aberrations: Involvement of phosphatidylinositol 3-kinase–related kinases and DNA replication fork movement. Mol Cancer Ther 2005; 4:1175-85. [PMID: 16093433 DOI: 10.1158/1535-7163.mct-05-0054] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Genotoxic treatments, such as UV light, camptothecin, and adozelesin, stall DNA replication and subsequently generate DNA strand breaks. Typically, DNA breaks are reflected by an increase in ataxia and Rad-related kinase (ATR)-regulated phosphorylation of H2AX (gammaH2AX) and require replication fork movement. This study examined the potential of the monofunctional DNA alkylating agent hedamycin, a powerful inhibitor of DNA replication, to induce DNA strand breaks, phosphorylated H2AX (gammaH2AX) foci, and chromosome aberrations. Hedamycin treatment of HCT116 carcinoma cells resulted in a rapid induction of DNA strand breaks accompanied by increasing H2AX phosphorylation and focalization. Unlike many other treatments that also stall replication, such as UV, camptothecin, and adozelesin, gammaH2AX formation was not suppressed in ATR-compromised cells but actually increased. Similarly, hedamycin induction of gammaH2AX is not dependent on ataxia telangiectasia mutated or DNA-protein kinase, and pretreatment of cells with the phosphatidylinositol 3-kinase-related kinase inhibitor caffeine did not substantially reduce induction of H2AX phosphorylation by hedamycin. Furthermore, the DNA replication inhibitor aphidicolin only modestly depressed hedamycin-induced gammaH2AX formation, indicating that hedamycin-induced DNA double-strand breaks are not dependent on fork progression. In contrast, camptothecin- and adozelesin-induced gammaH2AX was strongly suppressed by aphidicolin. Moreover, after 24 hours following a short-term hedamycin treatment, cells displayed high levels of breaks in interphase nuclear DNA and misjoined chromosomes in metaphase cells. Finally, focalization of a tightly bound form of Ku80 was observed in interphase cells, consistent with the subsequent appearance of chromosomal aberrations via abnormal nonhomologous end joining. Overall, this study has revealed a disparate type of DNA damage response to stalled replication induced by a bulky DNA adduct inducer, hedamycin, that seems not to be highly dependent on ATR or DNA replication.
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Affiliation(s)
- Lan Chun Tu
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Elm and Carlton Streets, Buffalo, NY 14263, USA
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Bililign T, Hyun CG, Williams JS, Czisny AM, Thorson JS. The hedamycin locus implicates a novel aromatic PKS priming mechanism. ACTA ACUST UNITED AC 2005; 11:959-69. [PMID: 15271354 DOI: 10.1016/j.chembiol.2004.04.016] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2004] [Revised: 04/19/2004] [Accepted: 04/26/2004] [Indexed: 11/18/2022]
Abstract
The biosynthetic gene cluster for the pluramycin-type antitumor antibiotic hedamycin has been cloned from Streptomyces griseoruber. Sequence analysis of the 45.6 kb region revealed a variety of unique features such as a fabH homolog (KSIII), an acyltransferase (AT) gene, a set of type I polyketide synthase (PKS) genes, and two putative C-glycosyltransferase genes. As the first report of the cloning of the biosynthetic gene cluster for the pluramycin antibiotics, this work suggests that the biosynthesis of pluramycins utilize an iterative type I PKS system for the generation of a novel starter unit that subsequently primes the type II PKS system. It also implicates the involvement of a second catalytic ketosynthase (KSIII) to regulate this unusual priming step. Gene disruption is used to confirm the importance of both type I and II PKS genes for the biosynthesis of hedamycin.
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Affiliation(s)
- Tsion Bililign
- Laboratory for Biosynthetic Chemistry, Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, Wisconsin 53705, USA
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Bililign T, Griffith BR, Thorson JS. Structure, activity, synthesis and biosynthesis of aryl-C-glycosides. Nat Prod Rep 2005; 22:742-60. [PMID: 16311633 DOI: 10.1039/b407364a] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The focus of this review is to highlight the structure, bioactivity and biosynthesis of naturally occurring aryl-C-glycosides. General synthetic methods and their relevance to proposed biochemical mechanisms for the aryl-C-glycoside bond formation are also presented.
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Affiliation(s)
- Tsion Bililign
- Chemistry Department, Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218, USA.
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Tu LC, Melendy T, Beerman TA. DNA damage responses triggered by a highly cytotoxic monofunctional DNA alkylator, hedamycin, a pluramycin antitumor antibiotic. Mol Cancer Ther 2004. [DOI: 10.1158/1535-7163.577.3.5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Long-term exposure (72 h) to hedamycin, a monofunctional DNA alkylator of the pluramycin class of antitumor antibiotics, decreased growth of mammalian cells by 50% at subnanomolar concentrations. Short-term treatment (4 h) rapidly reduced DNA synthesis by 50% also at subnanomolar concentrations, but substantially higher levels were needed to block RNA synthesis while protein synthesis even at very high hedamycin concentrations remained unaffected. Hedamycin treatment at concentrations below its growth IC50 induced only a transient and temporary accumulation of cells in G2. Somewhat higher concentrations resulted in substantial S-phase arrest, and at increasing concentrations, complete cell cycle arrest in G1 was observed without the appearance of a sub-G1 cell population. Neither inhibition of cell growth nor cell cycle arrest appeared to be dependent on ataxia and Rad-related kinase expression. DNA damage checkpoint proteins including p53, chk1, and chk2 were differentially activated by hedamycin depending on the concentration and duration of treatment. The level of downstream cell cycle regulators such as cdc25A, E2F1, cyclin E, and p21 were also altered under conditions that induced cell cycle arrest, but atypically, p21 overexpression was observed only in S-phase-arrested cells. Apoptotic indicators were only observed at moderate hedamycin concentrations associated with S-phase arrest, while increasing concentrations, when cells were arrested in G1, resulted in a reduction of these signals. Taken together, the responses of cells to hedamycin are distinct with regard to its effect on cell cycle but also in the unusual concentration-dependent manner of activation of DNA damage and cell cycle checkpoint proteins as well as the induction of apoptotic-associated events.
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Affiliation(s)
- Lan Chun Tu
- 1Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York and
| | - Thomas Melendy
- 2Witebsky Center for Microbial Pathogenesis and Immunology and Departments of Microbiology and Biochemistry, University at Buffalo School of Medicine and Biomedical Sciences, Buffalo, New York
| | - Terry A. Beerman
- 1Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, New York and
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Kim MY, Na Y, Vankayalapati H, Gleason-Guzman M, Hurley LH. Design, synthesis, and evaluation of psorospermin/quinobenzoxazine hybrids as structurally novel antitumor agents. J Med Chem 2003; 46:2958-72. [PMID: 12825936 DOI: 10.1021/jm030096i] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Topoisomerase II, an enzyme that catalyzes changes in the topology of DNA, plays several key roles in DNA metabolism and chromosome structure, and it is the primary cytotoxic target for a number of clinically important DNA intercalating agents such as doxorubicin. It seems likely that if these intercalating topoisomerase II poisons are structurally modified to also be DNA alkylating agents, they will have increased dwell time on the topoisomerase II-DNA complex and increased potency and selectivity for cancer cells. On the basis of insights into the mechanisms of action of psorospermin and the quinobenzoxazine A-62176 and molecular modeling studies of these compounds with duplex DNA, we have designed and synthesized a series of novel hybrid DNA-interactive compounds that alkylate DNA most efficiently at sequences directed by topoisomerase II. The epoxydihydrofuran ring of psorospermin was used as a DNA alkylating moiety, and this was fused to the pyridobenzophenoxazine ring of A-62176. The chlorohydrin ring opened form of the epoxide was also prepared and tested. These hybrid compounds showed enhanced DNA alkylating activity in the presence of topoisomerase II, exhibited significant activity against all the cancer cells tested at submicromolar concentrations, and were more potent than both parent compounds. However, the biochemical assays indicated that they lost some of the topoisomerase II and Mg(2+) dependency for reaction with DNA that is associated with psorospermin and A-62176, respectively.
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Affiliation(s)
- Mu-Yong Kim
- College of Pharmacy, The University of Arizona, 1703 E Mabel, Tucson, Arizona 85721, USA
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Owen EA, Burley GA, Carver JA, Wickham G, Keniry MA. Structural investigation of the hedamycin:d(ACCGGT)2 complex by NMR and restrained molecular dynamics. Biochem Biophys Res Commun 2002; 290:1602-8. [PMID: 11820806 DOI: 10.1006/bbrc.2002.6369] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Hedamycin, a member of the pluramycin family of drugs, displays a range of biological responses including antitumor and antimicrobial activity. The mechanism of action is via direct interaction with DNA through intercalation between the bases of the oligonucleotide and alkylation of a guanine residue at 5'-PyG-3' sites. There appears to be some minor structural differences between two earlier studies on the interaction of hedamycin with 5'-PyG-3' sites. In this study, a high-resolution NMR analysis of the hedamycin:d(ACCGGT)2 complex was undertaken in order to investigate the effect of replacing the thymine with a guanine at the preferred 5'-CGT-3' site. The resultant structure was compared with earlier work, with particular emphasis placed on the drug conformation. The structure of the hedamycin:d(ACCGGT)2 complex has many features in common with the two previous NMR structures of hedamycin:DNA complexes but differed in the conformation and orientation of the N,N-dimethylvancosamine saccharide of hedamycin in one of these structures. The preferential binding of hedamycin to 5'-CG-3' over 5'-TG-3' binding sites is explained in terms of the orientation and location of the N,N-dimethylvancosamine saccharide in the minor groove.
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Affiliation(s)
- Elisabeth A Owen
- Research School of Chemistry, Australian National University, Canberra, ACT 0200, Australia
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Nakatani K, Matsuno T, Adachi K, Hagihara S, Saito I. Selective intercalation of charge neutral intercalators into GG and CG steps: implication of HOMO-LUMO interaction for sequence-selective drug intercalation into DNA. J Am Chem Soc 2001; 123:5695-702. [PMID: 11403601 DOI: 10.1021/ja003956i] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have synthesized naphthopyranone epoxide 4 from D-isoascorbic acid together with its three diastereoisomers. DNA alkylation of ODNs containing 5'XGT3' and 5'TGY3' by 4 (11R, 13R), where X and Y are any nucleotide bases, occurred at all G residues except at G of the 5'TGC3' sequence. In contrast, the three other diastereoisomers of 4 showed only weak G alkylation activity. Differential (1)H NMR NOE of the 4-G adduct confirmed the G-N7 alkylation at the epoxide carbon of 4 with concomitant S(N)2 ring opening of the epoxide. Quantitative HPLC analysis of G alkylation efficiency for 4 showed the order of G alkylation susceptibility as TGGT approximately CGT >> TGA > AGT > TGT >> TGC. The order was fully consistent with those reported for aflatoxin B(1) oxide and kapurimycin A(3), suggesting that the sequence selectivity observed for these DNA alkylating agents is not structure dependent but most likely due to the intrinsic property of DNA sequences. We found that the order of G alkylation susceptibility obtained for 4 completely matched the calculated HOMO energy level of G-containing sequences. These results underscore that 4 is a unique molecular probe for ranking the HOMO level of G-containing sequences by well-known G alkylation chemistry and suggests that the intercalation of charge neutral intercalators is a HOMO-controlled process.
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Affiliation(s)
- K Nakatani
- Department of Synthetic Chemistry and Biological Chemistry, Faculty of Engineering, Kyoto University, CREST, Japan Science and Technology Corporation (JST), Kyoto 606-8501, Japan
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Nakatani K, Okamoto A, Saito I. Spezifische Alkylierung von Guanin, das einer Ausbuchtung von einem Nucleotid gegenüberliegt: eine chemische Sonde für DNA-Ausbuchtungen. Angew Chem Int Ed Engl 1999. [DOI: 10.1002/(sici)1521-3757(19991115)111:22<3581::aid-ange3581>3.0.co;2-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Pavlopoulos S, Bicknell W, Wickham G, Craik DJ. Characterization of the sequential non-covalent and covalent interactions of the antitumour antibiotic hedamycin with double stranded DNA by NMR spectroscopy. J Mol Recognit 1999; 12:346-54. [PMID: 10611644 DOI: 10.1002/(sici)1099-1352(199911/12)12:6<346::aid-jmr476>3.0.co;2-l] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Hedamycin, a member of the pluramycin class of antitumour antibiotics, consists of a planar anthrapyrantrione chromophore to which is attached two aminosugar rings at one end and a bisepoxide-containing sidechain at the other end. Binding to double-stranded DNA is known to involve both reversible and non-reversible modes of interaction. As a part of studies directed towards elucidating the structural basis for the observed 5'-pyGT-3' sequence selectivity of hedamycin, we conducted one-dimensional NMR titration experiments at low temperature using the hexadeoxyribonucleotide duplexes d(CACGTG)(2) and d(CGTACG)(2). Spectral changes which occurred during these titrations are consistent with hedamycin initially forming a reversible complex in slow exchange on the NMR timescale and binding through intercalation of the chromophore. Monitoring of this reversible complex over a period of hours revealed a second type of spectral change which corresponds with formation of a non-reversible complex.
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Affiliation(s)
- S Pavlopoulos
- Department of Medicinal Chemistry, Victorian College of Pharmacy, Monash University, Melbourne, Victoria, Australia
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32
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Lee SJ, Hurley LH. A Thymine:Thymine Mismatch Enhances the Pluramycin Alkylation Site Downstream of the TBP−TATA Box Complex. J Am Chem Soc 1999. [DOI: 10.1021/ja991607m] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Seung-Joo Lee
- Contribution from the Drug Dynamics Institute, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712
| | - Laurence H. Hurley
- Contribution from the Drug Dynamics Institute, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712
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Juarranz A, Villanueva A, Cañete M, Polo S, Domínguez V, Stockert JC. Microscopical and spectroscopic studies on the fluorescence of a daunomycin-aluminum complex. THE HISTOCHEMICAL JOURNAL 1999; 31:201-7. [PMID: 10421420 DOI: 10.1023/a:1003549500211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
In this study, the spectroscopic features and microscopical applications of the fluorescent daunomycin-Al3+ complex have been analyzed. In the presence of Al3+, the absorption spectrum of daunomycin showed a deep bathochromic shift and new peaks at 529 and 566 nm, whereas the fluorescence emission was considerably modified. The emission of daunomycin alone (peak at 560 nm under optimal excitation at 470 nm) decreased continuously from 0.5 to 24h after addition of Al3+ ions, and a new emission peak appeared at 580 nm (optimal excitation at 530 nm). Under the fluorescence microscope using green exciting light, nuclei from chicken blood smears and paraffin sections of rat embryos stained with daunomycin showed a weak emission, which greatly increased after treatment with Al3+ ions. The bright and stable fluorescence of chromatin DNA induced by daunomycin-Al3+ could be a valuable labelling method in fluorescence microscopy and DNA cytochemistry.
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Affiliation(s)
- A Juarranz
- Department of Biology, Faculty of Sciences, Autonomous University of Madrid, Cantoblanco, Spain
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Kwok Y, Zeng Q, Hurley LH. Topoisomerase II-mediated site-directed alkylation of DNA by psorospermin and its use in mapping other topoisomerase II poison binding sites. Proc Natl Acad Sci U S A 1998; 95:13531-6. [PMID: 9811834 PMCID: PMC24853 DOI: 10.1073/pnas.95.23.13531] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/1997] [Accepted: 09/11/1998] [Indexed: 12/16/2022] Open
Abstract
Psorospermin is a plant natural product that shows significant in vivo activity against P388 mouse leukemia. The molecular basis for this selectivity is unknown, although psorospermin has been demonstrated to intercalate into DNA and alkylate N7 of guanine. Significantly, the alkylation reactivity of psorospermin at specific sites on DNA increased 25-fold in the presence of topoisomerase II. In addition, psorospermin trapped the topoisomerase II-cleaved complex formation at the same site. These results imply that the efficacy of psorospermin is related to its interaction with the topoisomerase II-DNA complex. Because thermal treatment of (N7 guanine)-DNA adducts leads to DNA strand breakage, we were able to determine the site of alkylation of psorospermin within the topoisomerase II gate site and infer that intercalation takes place at the gate site between base pairs at the +1 and +2 positions. These results provide not only additional mechanistic information on the mode of action of the anticancer agent psorospermin but also structural insights into the design of an additional class of topoisomerase II poisons. Because the alkylation site for psorospermin in the presence of topoisomerase II can be assigned unambiguously and the intercalation site inferred, this drug is a useful probe for other topoisomerase poisons where the sites for interaction are less well defined.
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Affiliation(s)
- Y Kwok
- Drug Dynamics Institute, College of Pharmacy, University of Texas, Austin, TX 78712-1074, USA
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Nakatani K, Okamoto A, Matsuno T, Saito I. Highly Selective DNA Alkylation at the 5‘ Side G of a 5‘GG3‘ Sequence by an Aglycon Model of Pluramycin Antibiotics through Preferential Intercalation into the GG Step. J Am Chem Soc 1998. [DOI: 10.1021/ja980801q] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Kazuhiko Nakatani
- Contribution from the Department of Synthetic Chemistry and Biological Chemistry, Faculty of Engineering, Kyoto University, and CREST, Japan Science and Technology Corporation, Kyoto 606-8501, Japan
| | - Akimitsu Okamoto
- Contribution from the Department of Synthetic Chemistry and Biological Chemistry, Faculty of Engineering, Kyoto University, and CREST, Japan Science and Technology Corporation, Kyoto 606-8501, Japan
| | - Takahiro Matsuno
- Contribution from the Department of Synthetic Chemistry and Biological Chemistry, Faculty of Engineering, Kyoto University, and CREST, Japan Science and Technology Corporation, Kyoto 606-8501, Japan
| | - Isao Saito
- Contribution from the Department of Synthetic Chemistry and Biological Chemistry, Faculty of Engineering, Kyoto University, and CREST, Japan Science and Technology Corporation, Kyoto 606-8501, Japan
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36
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Synthesis of pyranose glycals via tungsten and molybdenum pentacarbonyl-induced alkynol cyclizations. Tetrahedron 1997. [DOI: 10.1016/s0040-4020(97)00366-9] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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37
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Iannitti P, Sheil MM, Wickham G. High Sensitivity and Fragmentation Specificity in the Analysis of Drug−DNA Adducts by Electrospray Tandem Mass Spectrometry. J Am Chem Soc 1997. [DOI: 10.1021/ja962439q] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Paula Iannitti
- Department of Chemistry, University of Wollongong NSW 2522, Australia
| | - Margaret M. Sheil
- Department of Chemistry, University of Wollongong NSW 2522, Australia
| | - Geoffrey Wickham
- Department of Chemistry, University of Wollongong NSW 2522, Australia
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Stassinopoulos A, Ji J, Gao X, Goldberg IH. Solution structure of a two-base DNA bulge complexed with an enediyne cleaving analog. Science 1996; 272:1943-6. [PMID: 8658168 DOI: 10.1126/science.272.5270.1943] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Nucleic acid bulges have been implicated in a number of biological processes and are specific cleavage targets for the enediyne antitumor antibiotic neocarzinostatin chromophore in a base-catalyzed, radical-mediated reaction. The solution structure of the complex between an analog of the bulge-specific cleaving species and an oligodeoxynucleotide containing a two-base bulge was elucidated by nuclear magnetic resonance. An unusual binding mode involves major groove recognition by the drug carbohydrate unit and tight fitting of the wedge-shaped drug in the triangular prism pocket formed by the two looped-out bulge bases and the neighboring base pairs. The two drug rings mimic helical DNA bases, complementing the bent DNA structure. The putative abstracting drug radical is 2.2 +/- 0.1 angstroms from the pro-S H5' of the target bulge nucleotide. This structure clarifies the mechanism of bulge recognition and cleavage by a drug and provides insight into the design of bulge-specific nucleic acid binding molecules.
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Affiliation(s)
- A Stassinopoulos
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA
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Mark Hansen,, Lee SJ, Cassady JM, Hurley LH. Molecular Details of the Structure of a Psorospermin−DNA Covalent/Intercalation Complex and Associated DNA Sequence Selectivity. J Am Chem Soc 1996. [DOI: 10.1021/ja960319c] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mark Hansen,
- Contribution from the Drug Dynamics Institute, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712-1074, and Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210
| | - Seung-Joo Lee
- Contribution from the Drug Dynamics Institute, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712-1074, and Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210
| | - John M. Cassady
- Contribution from the Drug Dynamics Institute, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712-1074, and Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210
| | - Laurence H. Hurley
- Contribution from the Drug Dynamics Institute, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712-1074, and Division of Medicinal Chemistry and Pharmacognosy, College of Pharmacy, The Ohio State University, Columbus, Ohio 43210
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Abstract
To gain insight into the interactions between transcriptional factor proteins and DNA, the DNA-reactive drugs (+)-CC-1065 and pluramycin were used to target specific protein-DNA complexes. The structural features of the complex between the transcriptional activator Sp1 and the 21-base-pair repeat of the early promoter region of SV40 DNA were examined using hydroxyl-radical footprinting; (+)-CC-1065, a sequence-specific minor groove bending probe; and circularization experiments. The results show that the 21-base-pair repeat region has an intrinsically in-phase bent structure that is stabilized upon saturation Sp1 binding by protein-DNA and protein-protein interactions to produce a looping structure. The intercalating drug pluramycin was used to probe the structural details of the interaction between the TATA binding protein (TBP) and the TATA box DNA sequence. TBP, which directs initiation of RNA transcription, exhibits two-fold symmetry and apparently interacts with the TATA box in a symmetrical fashion. However, the interaction results in an asymmetric effect, in that transcription is initiated only in the downstream direction. Using pluramycin as a probe, it was determined that TBP binding to the human myoglobin TATA sequences enhances pluramycin reactivity at a site immediately downstream of the TATA box. The implications on transcriptional control of ternary complexes comprised of transcriptional factors, DNA, and DNA-reactive compounds will be presented.
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Affiliation(s)
- D Henderson
- Drug Dynamics Institute, College of Pharmacy, University of Texas, Austin 78712, USA
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41
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Hansen MR, Hurley LH. Pluramycins. Old Drugs Having Modern Friends in Structural Biology. Acc Chem Res 1996. [DOI: 10.1021/ar950167a] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mark R. Hansen
- Drug Dynamics Institute, Division of Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712
| | - Laurence H. Hurley
- Drug Dynamics Institute, Division of Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712
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42
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Sun D, Hurley LH. TBP binding to the TATA box induces a specific downstream unwinding site that is targeted by pluramycin. CHEMISTRY & BIOLOGY 1995; 2:457-69. [PMID: 9383448 DOI: 10.1016/1074-5521(95)90263-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND The TATA-binding protein (TBP) is one of the major components of the human TFIID multiprotein complex. It is important in directing the initiation of RNA transcription at a site immediately downstream of the TATA sequence (TATA box) found in many eukaryotic promoters. The crystal structure of TBP complexed with an oligonucleotide containing the TATA box revealed a protein with an approximate two-fold symmetry which apparently has symmetrical interactions with DNA. It is not known how an asymmetric effect involving downstream activation can be produced by an apparent symmetric complex. We set out to examine the state of DNA in the TBP-DNA complex using pluramycin, a small molecular weight probe of DNA accessibility. RESULTS Binding of TBP to the TATA box facilitates intercalation of pluramycin at a defined site immediately downstream of the TATA sequence through an apparent transient unwinding of the DNA. Pluramycin adducts are detected by the production of DNA strand breakage products upon heating. Incubation of pluramycin with the TBP-DNA complex facilitates the trapping of the specific complex by intercalation. Gel mobility shift and circularization assays reveal that the binding of pluramycin on the 3'-side of the TATA box region considerably stabilizes the TBP-DNA complex. CONCLUSIONS We propose that the TBP-DNA-pluramycin ternary complex is a 'specific' binding mode in which TBP and pluramycin make compensatory alterations in DNA, accounting for the improved stability of the ternary complex. We also propose a model of the ternary complex that explains the observed asymmetric effect of TBP binding to the TATA box.
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Affiliation(s)
- D Sun
- Drug Dynamics Institute, College of Pharmacy, University of Texas at Austin 78712-1074, USA
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