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Marine-sourced anti-cancer and cancer pain control agents in clinical and late preclinical development. Mar Drugs 2014; 12:255-78. [PMID: 24424355 PMCID: PMC3917273 DOI: 10.3390/md12010255] [Citation(s) in RCA: 184] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Revised: 12/17/2013] [Accepted: 01/07/2014] [Indexed: 01/08/2023] Open
Abstract
The marine habitat has produced a significant number of very potent marine-derived agents that have the potential to inhibit the growth of human tumor cells in vitro and, in a number of cases, in both in vivo murine models and in humans. Although many agents have entered clinical trials in cancer, to date, only Cytarabine, Yondelis® (ET743), Eribulin (a synthetic derivative based on the structure of halichondrin B), and the dolastatin 10 derivative, monomethylauristatin E (MMAE or vedotin) as a warhead, have been approved for use in humans (Adcetris®). In this review, we show the compounds derived from marine sources that are currently in clinical trials against cancer. We have included brief discussions of the approved agents, where they are in trials to extend their initial approved activity (a common practice once an agent is approved), and have also included an extensive discussion of the use of auristatin derivatives as warheads, plus an area that has rarely been covered, the use of marine-derived agents to ameliorate the pain from cancers in humans, and to act as an adjuvant in immunological therapies.
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102
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Butler MS, Robertson AAB, Cooper MA. Natural product and natural product derived drugs in clinical trials. Nat Prod Rep 2014; 31:1612-61. [DOI: 10.1039/c4np00064a] [Citation(s) in RCA: 383] [Impact Index Per Article: 38.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The 25 Natural Product (NP)-derived drugs launched since 2008 and the 100 NP-derived compounds and 33 Antibody Drug Conjugates (ADCs) in clinical trials or in registration at the end of 2013 are reviewed.
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Affiliation(s)
- Mark S. Butler
- Division of Chemistry and Structural Biology
- Institute for Molecular Bioscience
- The University of Queensland
- Brisbane, Australia
| | - Avril A. B. Robertson
- Division of Chemistry and Structural Biology
- Institute for Molecular Bioscience
- The University of Queensland
- Brisbane, Australia
| | - Matthew A. Cooper
- Division of Chemistry and Structural Biology
- Institute for Molecular Bioscience
- The University of Queensland
- Brisbane, Australia
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103
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Shih CJ, Chen PY, Liaw CC, Lai YM, Yang YL. Bringing microbial interactions to light using imaging mass spectrometry. Nat Prod Rep 2014; 31:739-55. [DOI: 10.1039/c3np70091g] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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104
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Reimer D, Bode HB. A natural prodrug activation mechanism in the biosynthesis of nonribosomal peptides. Nat Prod Rep 2014; 31:154-9. [DOI: 10.1039/c3np70081j] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
ThisHighlightdescribes the recently discovered prodrug activation mechanism found in the biosynthesis of nonribosomally produced peptides and peptide/polyketide hybrids as well as related mechanisms.
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Affiliation(s)
- Daniela Reimer
- Merck Stiftungsprofessur für Molekulare Biotechnologie
- Fachbereich Biowissenschaften
- Goethe Universität Frankfurt
- 60438 Frankfurt am Main, Germany
| | - Helge B. Bode
- Merck Stiftungsprofessur für Molekulare Biotechnologie
- Fachbereich Biowissenschaften
- Goethe Universität Frankfurt
- 60438 Frankfurt am Main, Germany
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105
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Ferla MP, Thrash JC, Giovannoni SJ, Patrick WM. New rRNA gene-based phylogenies of the Alphaproteobacteria provide perspective on major groups, mitochondrial ancestry and phylogenetic instability. PLoS One 2013; 8:e83383. [PMID: 24349502 PMCID: PMC3859672 DOI: 10.1371/journal.pone.0083383] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 11/04/2013] [Indexed: 11/18/2022] Open
Abstract
Bacteria in the class Alphaproteobacteria have a wide variety of lifestyles and physiologies. They include pathogens of humans and livestock, agriculturally valuable strains, and several highly abundant marine groups. The ancestor of mitochondria also originated in this clade. Despite significant effort to investigate the phylogeny of the Alphaproteobacteria with a variety of methods, there remains considerable disparity in the placement of several groups. Recent emphasis on phylogenies derived from multiple protein-coding genes remains contentious due to disagreement over appropriate gene selection and the potential influences of systematic error. We revisited previous investigations in this area using concatenated alignments of the small and large subunit (SSU and LSU) rRNA genes, as we show here that these loci have much lower GC bias than whole genomes. This approach has allowed us to update the canonical 16S rRNA gene tree of the Alphaproteobacteria with additional important taxa that were not previously included, and with added resolution provided by concatenating the SSU and LSU genes. We investigated the topological stability of the Alphaproteobacteria by varying alignment methods, rate models, taxon selection and RY-recoding to circumvent GC content bias. We also introduce RYMK-recoding and show that it avoids some of the information loss in RY-recoding. We demonstrate that the topology of the Alphaproteobacteria is sensitive to inclusion of several groups of taxa, but it is less affected by the choice of alignment and rate methods. The majority of topologies and comparative results from Approximately Unbiased tests provide support for positioning the Rickettsiales and the mitochondrial branch within a clade. This composite clade is a sister group to the abundant marine SAR11 clade (Pelagibacterales). Furthermore, we add support for taxonomic assignment of several recently sequenced taxa. Accordingly, we propose three subclasses within the Alphaproteobacteria: the Caulobacteridae, the Rickettsidae, and the Magnetococcidae.
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Affiliation(s)
- Matteo P. Ferla
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - J. Cameron Thrash
- Department of Microbiology, Oregon State University, Corvallis, Oregon, United States of America
- Department of Biological Sciences, Louisiana State University, Baton Rouge, Louisiana, United States of America
| | - Stephen J. Giovannoni
- Department of Microbiology, Oregon State University, Corvallis, Oregon, United States of America
| | - Wayne M. Patrick
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
- * E-mail:
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Ankisetty S, Khan SI, Avula B, Gochfeld D, Khan IA, Slattery M. Chlorinated didemnins from the tunicate Trididemnum solidum. Mar Drugs 2013; 11:4478-86. [PMID: 24284424 PMCID: PMC3853740 DOI: 10.3390/md11114478] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2013] [Revised: 10/25/2013] [Accepted: 10/29/2013] [Indexed: 11/16/2022] Open
Abstract
Chemical investigation of the tunicate Trididemnum solidum resulted in the isolation of two new chlorinated compounds belonging to the didemnin class, along with two known compounds didemnin A and didemnin B. The structural determination of the compounds was based on extensive NMR and mass spectroscopic analysis. The isolated compounds 1-4 were tested for their anti-inflammatory activity using in vitro assays for inhibition of inducible nitric oxide synthase (iNOS) and nuclear factor-kappa B (NF-κB) activity. The anti-cell proliferative activity of the above compounds was also evaluated against four solid tumor cell lines.
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Affiliation(s)
- Sridevi Ankisetty
- Department of Pharmacognosy, School of Pharmacy, The University of Mississippi, University, MS 38677, USA; E-Mails: (S.I.K.); (I.A.K.)
| | - Shabana I. Khan
- Department of Pharmacognosy, School of Pharmacy, The University of Mississippi, University, MS 38677, USA; E-Mails: (S.I.K.); (I.A.K.)
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, The University of Mississippi, University, MS 38677, USA; E-Mails: (B.A.); (D.G.)
| | - Bharathi Avula
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, The University of Mississippi, University, MS 38677, USA; E-Mails: (B.A.); (D.G.)
| | - Deborah Gochfeld
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, The University of Mississippi, University, MS 38677, USA; E-Mails: (B.A.); (D.G.)
| | - Ikhlas A. Khan
- Department of Pharmacognosy, School of Pharmacy, The University of Mississippi, University, MS 38677, USA; E-Mails: (S.I.K.); (I.A.K.)
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, The University of Mississippi, University, MS 38677, USA; E-Mails: (B.A.); (D.G.)
| | - Marc Slattery
- Department of Pharmacognosy, School of Pharmacy, The University of Mississippi, University, MS 38677, USA; E-Mails: (S.I.K.); (I.A.K.)
- National Center for Natural Products Research, Research Institute of Pharmaceutical Sciences, The University of Mississippi, University, MS 38677, USA; E-Mails: (B.A.); (D.G.)
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Microbial natural products: molecular blueprints for antitumor drugs. J Ind Microbiol Biotechnol 2013; 40:1181-210. [PMID: 23999966 DOI: 10.1007/s10295-013-1331-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 08/07/2013] [Indexed: 12/18/2022]
Abstract
Microbes from two of the three domains of life, the Prokarya, and Eukarya, continue to serve as rich sources of structurally complex chemical scaffolds that have proven to be essential for the development of anticancer therapeutics. This review describes only a handful of exemplary natural products and their derivatives as well as those that have served as elegant blueprints for the development of novel synthetic structures that are either currently in use or in clinical or preclinical trials together with some of their earlier analogs in some cases whose failure to proceed aided in the derivation of later compounds. In every case, a microbe has been either identified as the producer of secondary metabolites or speculated to be involved in the production via symbiotic associations. Finally, rapidly evolving next-generation sequencing technologies have led to the increasing availability of microbial genomes. Relevant examples of genome mining and genetic manipulation are discussed, demonstrating that we have only barely scratched the surface with regards to harnessing the potential of microbes as sources of new pharmaceutical leads/agents or biological probes.
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108
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Affiliation(s)
- Nicole B. Lopanik
- Department of Biology; Georgia State University; Atlanta Georgia 30303 USA
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109
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Pu JY, Peng C, Tang MC, Zhang Y, Guo JP, Song LQ, Hua Q, Tang GL. Naphthyridinomycin Biosynthesis Revealing the Use of Leader Peptide to Guide Nonribosomal Peptide Assembly. Org Lett 2013; 15:3674-7. [DOI: 10.1021/ol401549y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Jin-Yue Pu
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China, and State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Chao Peng
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China, and State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Man-Cheng Tang
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China, and State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Yue Zhang
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China, and State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Jian-Ping Guo
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China, and State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Li-Qiang Song
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China, and State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Qiang Hua
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China, and State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Gong-Li Tang
- State Key Laboratory of Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China, and State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
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Walsh CT, O'Brien RV, Khosla C. Nonproteinogenic amino acid building blocks for nonribosomal peptide and hybrid polyketide scaffolds. Angew Chem Int Ed Engl 2013; 52:7098-124. [PMID: 23729217 PMCID: PMC4634941 DOI: 10.1002/anie.201208344] [Citation(s) in RCA: 263] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Indexed: 12/24/2022]
Abstract
Freestanding nonproteinogenic amino acids have long been recognized for their antimetabolite properties and tendency to be uncovered to reactive functionalities by the catalytic action of target enzymes. By installing them regiospecifically into biogenic peptides and proteins, it may be possible to usher a new era at the interface between small molecule and large molecule medicinal chemistry. Site-selective protein functionalization offers uniquely attractive strategies for posttranslational modification of proteins. Last, but not least, many of the amino acids not selected by nature for protein incorporation offer rich architectural possibilities in the context of ribosomally derived polypeptides. This Review summarizes the biosynthetic routes to and metabolic logic for the major classes of the noncanonical amino acid building blocks that end up in both nonribosomal peptide frameworks and in hybrid nonribosomal peptide-polyketide scaffolds.
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Affiliation(s)
- Christopher T Walsh
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
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111
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Walsh CT, O'Brien RV, Khosla C. Nichtproteinogene Aminosäurebausteine für Peptidgerüste aus nichtribosomalen Peptiden und hybriden Polyketiden. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201208344] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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112
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Kenney GE, Rosenzweig AC. Genome mining for methanobactins. BMC Biol 2013; 11:17. [PMID: 23442874 PMCID: PMC3621798 DOI: 10.1186/1741-7007-11-17] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 02/26/2013] [Indexed: 01/27/2023] Open
Abstract
Background Methanobactins (Mbns) are a family of copper-binding natural products involved in copper uptake by methanotrophic bacteria. The few Mbns that have been structurally characterized feature copper coordination by two nitrogen-containing heterocycles next to thioamide groups embedded in a peptidic backbone of varying composition. Mbns are proposed to derive from post-translational modification of ribosomally synthesized peptides, but only a few genes encoding potential precursor peptides have been identified. Moreover, the relevance of neighboring genes in these genomes has been unclear. Results The potential for Mbn production in a wider range of bacterial species was assessed by mining microbial genomes. Operons encoding Mbn-like precursor peptides, MbnAs, were identified in 16 new species, including both methanotrophs and, surprisingly, non-methanotrophs. Along with MbnA, the core of the operon is formed by two putative biosynthetic genes denoted MbnB and MbnC. The species can be divided into five groups on the basis of their MbnA and MbnB sequences and their operon compositions. Additional biosynthetic proteins, including aminotransferases, sulfotransferases and flavin adenine dinucleotide (FAD)-dependent oxidoreductases were also identified in some families. Beyond biosynthetic machinery, a conserved set of transporters was identified, including MATE multidrug exporters and TonB-dependent transporters. Additional proteins of interest include a di-heme cytochrome c peroxidase and a partner protein, the roles of which remain a mystery. Conclusions This study indicates that Mbn-like compounds may be more widespread than previously thought, but are not present in all methanotrophs. This distribution of species suggests a broader role in metal homeostasis. These data provide a link between precursor peptide sequence and Mbn structure, facilitating predictions of new Mbn structures and supporting a post-translational modification biosynthetic pathway. In addition, testable models for Mbn transport and for methanotrophic copper regulation have emerged. Given the unusual modifications observed in Mbns characterized thus far, understanding the roles of the putative biosynthetic proteins is likely to reveal novel pathways and chemistry.
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Affiliation(s)
- Grace E Kenney
- Departments of Molecular Biosciences and of Chemistry, Northwestern University, Evanston, IL 60208, USA
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113
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Xu F, Kong D, He X, Zhang Z, Han M, Xie X, Wang P, Cheng H, Tao M, Zhang L, Deng Z, Lin S. Characterization of streptonigrin biosynthesis reveals a cryptic carboxyl methylation and an unusual oxidative cleavage of a N-C bond. J Am Chem Soc 2013; 135:1739-48. [PMID: 23301954 DOI: 10.1021/ja3069243] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Streptonigrin (STN, 1) is a highly functionalized aminoquinone alkaloid with broad and potent antitumor activity. Here, we reported the biosynthetic gene cluster of STN identified by genome scanning of a STN producer Streptomyces flocculus CGMCC4.1223. This cluster consists of 48 genes determined by a series of gene inactivations. On the basis of the structures of intermediates and shunt products accumulated from five specific gene inactivation mutants and feeding experiments, the biosynthetic pathway was proposed, and the sequence of tailoring steps was preliminarily determined. In this pathway, a cryptic methylation of lavendamycin was genetically and biochemically characterized to be catalyzed by a leucine carboxyl methyltransferase StnF2. A [2Fe-2S](2+) cluster-containing aromatic ring dioxygenase StnB1/B2 system was biochemically characterized to catalyze a regiospecific cleavage of the N-C8' bond of the indole ring of the methyl ester of lavendamycin. This work provides opportunities to illuminate the enzymology of novel reactions involved in this pathway and to create, using genetic and chemo-enzymatic methods, new streptonigrinoid analogues as potential therapeutic agents.
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Affiliation(s)
- Fei Xu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China
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114
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Davidsen JM, Bartley DM, Townsend CA. Non-ribosomal propeptide precursor in nocardicin A biosynthesis predicted from adenylation domain specificity dependent on the MbtH family protein NocI. J Am Chem Soc 2013; 135:1749-59. [PMID: 23330869 DOI: 10.1021/ja307710d] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Nocardicin A is a monocyclic β-lactam isolated from the actinomycete Nocardia uniformis that shows moderate antibiotic activity against a broad spectrum of gram-negative bacteria. The monobactams are of renewed interest due to emerging gram-negative strains resistant to clinically available penicillins and cephalosporins. Like isopenicillin N, nocardicin A has a tripeptide core of non-ribosomal origin. Paradoxically, the nocardicin A gene cluster encodes two non-ribosomal peptide synthetases (NRPSs), NocA and NocB, predicted to encode five modules pointing to a pentapeptide precursor in nocardicin A biosynthesis, unless module skipping or other nonlinear reactions are occurring. Previous radiochemical incorporation experiments and bioinformatic analyses predict the incorporation of p-hydroxy-L-phenylglycine (L-pHPG) into positions 1, 3, and 5 and L-serine into position 4. No prediction could be made for position 2. Multidomain constructs of each module were heterologous expressed in Escherichia coli for determination of the adenylation domain (A-domain) substrate specificity using the ATP/PPi exchange assay. Three of the five A-domains, from modules 1, 2, and 4, required the addition of stoichiometric amounts of MbtH family protein NocI to detect exchange activity. On the basis of these analyses, the predicted product of the NocA and NocB NRPSs is L-pHPG-L-Arg-D-pHPG-L-Ser-L-pHPG, a pentapeptide. Despite being flanked by non-proteinogenic amino acids, proteolysis of this pentapeptide by trypsin yields two fragments from cleavage at the C terminus of the L-Arg residue. Thus, a proteolytic step is likely involved in the biosynthesis of nocardicin A, a rare but precedented editing event in the formation of non-ribosomal natural products that is supported by the identification of trypsin-encoding genes in N. uniformis.
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Affiliation(s)
- Jeanne M Davidsen
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
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115
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Ross AC, Xu Y, Lu L, Kersten RD, Shao Z, Al-Suwailem AM, Dorrestein PC, Qian PY, Moore BS. Biosynthetic multitasking facilitates thalassospiramide structural diversity in marine bacteria. J Am Chem Soc 2013; 135:1155-62. [PMID: 23270364 DOI: 10.1021/ja3119674] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Thalassospiramides A and B are immunosuppressant cyclic lipopeptides first reported from the marine α-proteobacterium Thalassospira sp. CNJ-328. We describe here the discovery and characterization of an extended family of 14 new analogues from four Tistrella and Thalassospira isolates. These potent calpain 1 protease inhibitors belong to six structure classes in which the length and composition of the acylpeptide side chain varies extensively. Genomic sequence analysis of the thalassospiramide-producing microbes revealed related, genus-specific biosynthetic loci encoding hybrid nonribosomal peptide synthetase/polyketide synthases consistent with thalassospiramide assembly. The bioinformatics analysis of the gene clusters suggests that structural diversity, which ranges from the 803.4 Da thalassospiramide C to the 1291.7 Da thalassospiramide F, results from a complex sequence of reactions involving amino acid substrate channeling and enzymatic multimodule skipping and iteration. Preliminary biochemical analysis of the N-terminal nonribosomal peptide synthetase module from the Thalassospira TtcA megasynthase supports a biosynthetic model in which in cis amino acid activation competes with in trans activation to increase the range of amino acid substrates incorporated at the N terminus.
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Affiliation(s)
- Avena C Ross
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92037, USA
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Abstract
Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) imaging mass spectrometry (IMS) applied directly to microbes on agar-based medium captures global information about microbial molecules, allowing for direct correlation of chemotypes to phenotypes. This tool was developed to investigate metabolic exchange factors of intraspecies, interspecies, and polymicrobial interactions. Based on our experience of the thousands of images we have generated in the laboratory, we present five steps of microbial IMS: culturing, matrix application, dehydration of the sample, data acquisition, and data analysis/interpretation. We also address the common challenges encountered during sample preparation, matrix selection and application, and sample adherence to the MALDI target plate. With the practical guidelines described herein, microbial IMS use can be extended to bio-based agricultural, biofuel, diagnostic, and therapeutic discovery applications.
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Sikorska J, Hau AM, Anklin C, Parker-Nance S, Davies-Coleman MT, Ishmael JE, McPhail KL. Mandelalides A-D, cytotoxic macrolides from a new Lissoclinum species of South African tunicate. J Org Chem 2012; 77:6066-75. [PMID: 22712890 DOI: 10.1021/jo3008622] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mandelalides A-D are variously glycosylated, unusual polyketide macrolides isolated from a new species of Lissoclinum ascidian collected from South Africa, Algoa Bay near Port Elizabeth and the surrounding Nelson Mandela Metropole. Their planar structures were elucidated on submilligram samples by comprehensive analysis of 1D and 2D NMR data, supported by mass spectrometry. The assignment of relative configuration was accomplished by consideration of homonuclear and heteronuclear coupling constants in tandem with ROESY data. The absolute configuration was assigned for mandelalide A after chiral GC-MS analysis of the hydrolyzed monosaccharide (2-O-methyl-α-L-rhamnose) and consideration of ROESY correlations between the monosaccharide and aglycone in the intact natural product. The resultant absolute configuration of the mandelalide A macrolide was extrapolated to propose the absolute configurations of mandelalides B-D. Remarkably, mandelalide B contained the C-4' epimeric 2-O-methyl-6-dehydro-α-L-talose. Mandelalides A and B showed potent cytotoxicity to human NCI-H460 lung cancer cells (IC(50), 12 and 44 nM, respectively) and mouse Neuro-2A neuroblastoma cells (IC(50), 29 and 84 nM, respectively).
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Affiliation(s)
- Justyna Sikorska
- Department of Pharmaceutical Sciences, College of Pharmacy, 203 Pharmacy Building, Oregon State University, Corvallis, Oregon 97331, USA
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