Thielavins: tuned biosynthesis and LR-HSQMBC for structure elucidation

Subeh, Zeinab Y. Al; Raja, Huzefa A.; Maldonado, Amanda C; Burdette, Joanna E.; Pearce, Cedric J.; Oberlies, Nicholas H.

doi:10.1038/s41429-021-00405-6

Cited by 9 publications

(12 citation statements)

References 26 publications

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“…The relatively small molecular weight of these two benzopyranones ( 19 and 20 ), their low hydrogen to carbon ratio, and the sparsity of 1 H- 1 H coupling imparts difficulty in confirming the positions of the aromatic substituents. Therefore, NOESY experiments were used to further facilitate the structure elucidation of these compounds, and this approach has been implemented for other hydrogen-deficient natural products [ 10 ]. The NOESY correlations between H-2/CH 3 -11, CH 3 -11/H-10, H-10/CH 3 O-9 confirmed the structure of 19 (Figs.…”

Section: Resultsmentioning

confidence: 99%

“…It is well known that growth conditions and fermentation media have a significant impact on the fungal biosynthetic machinery [ 3 ]. Both the yield and the composition of fungal secondary metabolites are affected by environmental factors [ 4 – 10 ]. The “One-Strain-Many Compounds” approach (OSMAC) was popularized by Bode et al [ 11 ] as a powerful strategy to increase the number of secondary metabolites available from one microbial source, and this involves the alteration of easily accessible cultivation parameters, i.e., media composition.…”

Section: Introductionmentioning

confidence: 99%

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Media and strain studies for the scaled production of cis-enone resorcylic acid lactones as feedstocks for semisynthesis

et al. 2021

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Resorcylic acid lactones (RALs) with a cis-enone moiety, represented by hypothemycin (1) and (5Z)-7-oxozeaenol (2), are fungal secondary metabolites with irreversible inhibitory activity against protein kinases, with particularly selective activity for inhibition of TAK1 (transforming growth factor beta-activated kinase 1). Gram-scale quantities of these compounds were needed as feedstock for semi-synthesizing RAL-analogues in a step-economical fashion. To do so, this study had three primary goals: identifying fungi that biosynthesized 1 and 2, enhancing their production by optimizing the fermentation conditions on the lab scale, and developing straight forward purification processes. After evaluating 536 fungal extracts via an in-house dereplication protocol, three strains were identified as producing cis-enone RALs (i.e., MSX78495, MSX63935, MSX45109). Screening these fungal strains on three grain-based media revealed enhanced production of 1 by strain MSX78495 on oatmeal medium, while rice medium increased the biosynthesis of 2 by strain MSX63935. Furthermore, the purification processes were improved, moving away from HPLC purification to utilizing two to four cycles of resuspension and centrifugation in small volumes of organic solvents, generating gram-scale quantities of these metabolites readily. In addition, studying the chemistry profiles of strains MSX78495 and MSX63935 resulted in the isolation of ten other RALs (3-12), two radicinin analogues (13-14), and six benzopyranones (15-20), with 19 and 20 being newly described chlorinated benzopyranones.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Media and strain studies for the scaled production of cis-enone resorcylic acid lactones as feedstocks for semisynthesis

et al. 2021

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“…Chemical reagents were used as received from chemical vendors. Hypothemycin was isolated and purified from solid-state cultures of strain MSX78495 as previously described . Unless otherwise stated, all reactions were carried out under an atmosphere of dry nitrogen in dried glassware.…”

Section: Methodsmentioning

confidence: 99%

“…To evaluate the cytotoxic activity of the generated hypothemycin analogues against human melanoma cancer cells (MDA-MB-435) and human ovarian cancer cells (OVCAR3), the previously described protocol was followed . In brief, a total of 5000 cells were seeded per well of a 96-well clear, flat-bottom plate (Microtest 96, Falcon) and incubated overnight (37 °C in 5% CO 2 ).…”

Section: Methodsmentioning

confidence: 99%

Semisynthesis of Hypothemycin Analogues Targeting the C8–C9 Diol

Subeh

Ustoyev

et al. 2022

J. Nat. Prod.

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Hypothemycin, an epoxide derivative of (5Z)-7-oxozeaenol, was used in the semisynthesis of a series of C8–C9 diol derivatives, with many inhibiting TAK1 at submicromolar concentrations. A step-economical approach was chosen, whereby nonselective reactions functionalized the diol to generate multiple analogues in a single reaction. Using this approach, 35 analogues were synthesized using 12 reactions, providing a wealth of information about the role that the C8–C9 diol plays in TAK1 inhibition and cytotoxicity in ovarian and breast cancer cell lines. Monofunctionalized analogues exhibited strong inhibition of TAK1, showing potential for modification of this section of the molecule to assist with solubility, formulation, and other desirable properties. Most analogues were cytotoxic, and three compounds had similar or slightly increased potency with >100-fold improvement in solubility profiles.

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“…These assays were performed exactly as detailed recently. 50 Compound 1 was analyzed with four technical replicates and three biological replicates and was >90% pure by UPLC.…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

Opportunities and Limitations for Assigning Relative Configurations of Antibacterial Bislactones using GIAO NMR Shift Calculations

et al. 2021

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Four new bislactones, dihydroacremonol (1), clonostachyone (2), acremodiol B (3), and acremodiol C (4), along with one known compound, hymeglusin (5), were isolated from cultures of two fungal strains (MSX59876 and MSX59260). Both strains were identified based on phylogenetic analysis of molecular data as Clonostachys spp.; yet, they biosynthesized a suite of related, but different, secondary metabolites. Given the challenges associated with elucidating the structures and configurations of bislactones, GIAO NMR calculations were tested as a complement to traditional NMR and HRESIMS experiments. Fortuitously, the enantiomer of the new natural product (4) was known as a synthetic compound, and the predicted configuration from GIAO NMR calculations (i.e., for the relative configuration) and optical rotation calculations (i.e., for the absolute configuration) matched those of the synthesis product. These results engendered confidence in using similar procedures, particularly the mixture of GIAO NMR shift calculations coupled with an orthogonal technique, to predict the configuration of 1−3; however, there were important limitations, which are discussed for each of these. The metabolites displayed antimicrobial activities, with compounds 1 and 4 being the most potent against Staphylococcus aureus with MICs of 1 and 4 μg/mL, respectively.

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Thielavins: tuned biosynthesis and LR-HSQMBC for structure elucidation

Cited by 9 publications

References 26 publications

Media and strain studies for the scaled production of cis-enone resorcylic acid lactones as feedstocks for semisynthesis

Media and strain studies for the scaled production of cis-enone resorcylic acid lactones as feedstocks for semisynthesis

Semisynthesis of Hypothemycin Analogues Targeting the C8–C9 Diol

Opportunities and Limitations for Assigning Relative Configurations of Antibacterial Bislactones using GIAO NMR Shift Calculations

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