Natural products (NPs) and NP derivatives are an unrivaled, but highly under-represented, resource. Arguably among the most notable natural products discovered to date, the 10-membered enediynes - exemplified by the saccharide-fused calicheamicins (CLM) and the anthraquinone-fused dynemicins (DYN) - offer unprecedented molecular architecture, spectacular biological activity and demonstrated clinical utility. The objective of the first phase of this study (CA84374, years 1-4) was to i) clone and characterize the CLM gene cluster from M. echinospora, ii) develop the genetic tools to address CLM biosynthesis in M. echinospora, iii) investigate the mechanism(s) of CLM self-resistance, and iv) initiate aryltetrasaccharide biosynthetic studies. With these goals largely achieved and new tools/information in place, the second phase of this program (CA84374, years 5-9) was focused upon i) cloning and characterization of the DYN gene cluster from M. chersina, ii) development of genetic tools to address DYN biosynthesis in M. chersina, iii) initiating enediyne core biosynthetic studies, iv) structurally characterization of the CLM self-sacrifice resistance protein CalC, and v) the elucidation of key aryltetrasaccharide biosynthetic transformations (sugar N-oxidation, thiosugar formation and GT-catalyzed aryltetrasaccharide assembly). The successful completion of the majority of phase II aims enables the proposed course of study for this competitive renewal. Specifically, we will focus upon i) extending our understanding of enediyne core biosynthesis, ii) delineating the potential role of CalC in regulating CLM production in M. echinospora, iii) completing the study of key aryltetrasaccharide sugar nucleotide transformations (sulfur installation and sequential C-C alkylation of the N-alkyl dideoxypentose), iv) initiating an enediyne structural biology program and v) synthesizing and evaluating (neo)glycorandomized libraries of CLM and DYN.

Public Health Relevance

This is a second competitive renewal of a productive program ((CA84374) targeting the biosynthesis of 10-membered enediynes (calicheamicin and dynemicin) - a novel class of anticancer natural products. The program is anticipated to provide pioneering discoveries in enzyme-catalyzed chemistries, new tools for the chemical diversification of complex natural products and unique anticancer lead compounds.

National Institute of Health (NIH)
National Cancer Institute (NCI)
Research Project (R01)
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Synthetic and Biological Chemistry B Study Section (SBCB)
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Fu, Yali
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University of Kentucky
Schools of Pharmacy
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Singh, Shanteri; Zhang, Jianjun; Huber, Tyler D et al. (2014) Facile chemoenzymatic strategies for the synthesis and utilization of S-adenosyl-(L)-methionine analogues. Angew Chem Int Ed Engl 53:3965-9
Singh, Shanteri; Peltier-Pain, Pauline; Tonelli, Marco et al. (2014) A general NMR-based strategy for the in situ characterization of sugar-nucleotide-dependent biosynthetic pathways. Org Lett 16:3220-3
Singh, Shanteri; Nandurkar, Nitin S; Thorson, Jon S (2014) Characterization of the calicheamicin orsellinate C2-O-methyltransferase CalO6. Chembiochem 15:1418-21
Wang, Fengbin; Singh, Shanteri; Zhang, Jianjun et al. (2014) Understanding molecular recognition of promiscuity of thermophilic methionine adenosyltransferase sMAT from SulfolobusĀ solfataricus. FEBS J 281:4224-39
Goff, Randal D; Thorson, Jon S (2014) Neoglycosylation and neoglycorandomization: Enabling tools for the discovery of novel glycosylated bioactive probes and early stage leads. Medchemcomm 5:1036-1047
Elshahawi, Sherif I; Ramelot, Theresa A; Seetharaman, Jayaraman et al. (2014) Structure-guided functional characterization of enediyne self-sacrifice resistance proteins, CalU16 and CalU19. ACS Chem Biol 9:2347-58
Singh, Shanteri; Chang, Aram; Helmich, Kate E et al. (2013) Structural and functional characterization of CalS11, a TDP-rhamnose 3'-O-methyltransferase involved in calicheamicin biosynthesis. ACS Chem Biol 8:1632-9
Chang, Aram; Singh, Shanteri; Bingman, Craig A et al. (2011) Structural characterization of CalO1: a putative orsellinic acid methyltransferase in the calicheamicin-biosynthetic pathway. Acta Crystallogr D Biol Crystallogr 67:197-203
Chang, Aram; Singh, Shanteri; Helmich, Kate E et al. (2011) Complete set of glycosyltransferase structures in the calicheamicin biosynthetic pathway reveals the origin of regiospecificity. Proc Natl Acad Sci U S A 108:17649-54
Goff, Randal D; Singh, Shanteri; Thorson, Jon S (2011) Glycosyloxyamine neoglycosylation: a model study using calicheamicin. ChemMedChem 6:774-6

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