-
Molecules (Basel, Switzerland) Mar 2023Six new polyene carboxylic acids named serpentemycins E-J (-), together with three known analogs (-), were isolated from the fermentation medium of sp. TB060207, which...
Six new polyene carboxylic acids named serpentemycins E-J (-), together with three known analogs (-), were isolated from the fermentation medium of sp. TB060207, which was isolated from arid soil collected from Tibet, China. The structures of the new compounds were elucidated mainly on the basis of HR-ESI-MS and NMR spectroscopic analyses. The inhibitory activities of compounds - against NO production in LPS-activated RAW264.7 cells were evaluated. Compound has an inhibition rate of 87.09% to 60.53% at concentrations ranging from 5.0 to 40.0 µM.
Topics: Carboxylic Acids; Tibet; Streptomyces; Magnetic Resonance Spectroscopy; Polyenes
PubMed: 36985551
DOI: 10.3390/molecules28062579 -
Journal of the American Chemical Society Jan 2008This communication describes the discovery of air-stable and highly versatile B-protected haloalkenylboronic acid building blocks for iterative cross-coupling. These...
This communication describes the discovery of air-stable and highly versatile B-protected haloalkenylboronic acid building blocks for iterative cross-coupling. These reagents enable the total synthesis of polyene natural products with extraordinary levels of simplicity, efficiency, and modularity. Specifically, all--retinal, β-parinaric acid, and one-half the amphotericin B macrolide skeleton were prepared using only the Suzuki-Miyaura reaction in an iterative manner to bring together collections of simple and readily-accessible building blocks. In contrast to their boronic acid counterparts, the intermediate polyenylboronate esters are remarkably stable (to both column purification and storage), which is critical to their successful utilization. Moreover, the reactive boronic acids can be cleanly liberated using very mild aqueous base. These advances have enabled preparation of the longest polyene ever synthesized using the SM reaction. We additionally report, to the best of our knowledge, the first triply metal selective (Zn vs. Sn and B) cross-coupling reaction, the first selective cross-coupling with a differentially-ligated diboron reagent, and the first cross-couplings between polyenylchlorides and vinylboronic acids. Collectively, these new building blocks and methods can dramatically improve the way polyene natural products and their derivatives are synthesized in the laboratory.
Topics: Amphotericin B; Antifungal Agents; Biological Products; Boronic Acids; Polyenes
PubMed: 18081295
DOI: 10.1021/ja078129x -
Journal of Microbiology and... Jul 2022As valuable antibiotics, microbial natural products have been in use for decades in various fields. Among them are polyene compounds including nystatin, amphotericin,...
As valuable antibiotics, microbial natural products have been in use for decades in various fields. Among them are polyene compounds including nystatin, amphotericin, and nystatin-like polyenes (NPPs). Polyene macrolides are known to possess various biological effects, such as antifungal and antiviral activities. NPP A1, which is produced by , contains a unique disaccharide moiety in the tetraene macrolide backbone. NPP B1, with a heptane structure and improved antifungal activity, was then developed via genetic manipulation of the NPP A1 biosynthetic gene cluster (BGC). Here, we generated a artificial chromosomal DNA library to isolate a large-sized NPP B1 BGC. The NPP B1 BGC was successfully isolated from chromosome through the construction and screening of a bacterial artificial chromosome (BAC) library, even though the isolated 140-kb BAC clone (named pNPPB1s) lacked approximately 8 kb of the right-end portion of the NPP B1 BGC. The additional introduction of the pNPPB1s as well as co-expression of the 32-kb portion including the missing 8 kb led to a 7.3-fold increase in the production level of NPP B1 in . The qRT-PCR confirmed that the transcription level of NPP B1 BGC was significantly increased in the strain containing two copies of the NPP B1 BGCs. Interestingly, the NPP B1 exhibited a previously unidentified SARS-CoV-2 RNA-dependent RNA polymerase (RdRp) inhibition activity in vitro. These results suggest that the BAC cloning of a large-sized, natural product BGC is a valuable approach for titer improvement and biological activity screening of natural products in actinomycetes.
Topics: Anti-Bacterial Agents; Antifungal Agents; Biological Products; COVID-19; Chromosomes, Artificial, Bacterial; Cloning, Molecular; Humans; Macrolides; Multigene Family; Nystatin; Polyenes; RNA, Viral; RNA-Dependent RNA Polymerase; SARS-CoV-2; Streptomyces
PubMed: 35719079
DOI: 10.4014/jmb.2205.05036 -
American Journal of Health-system... Feb 2016Results of a study to determine the stability of tacrolimus solutions stored in polyolefin containers under various temperature conditions are reported.
PURPOSE
Results of a study to determine the stability of tacrolimus solutions stored in polyolefin containers under various temperature conditions are reported.
METHODS
Triplicate solutions of tacrolimus (0.001, 0.01, and 0.1 mg/mL) in 0.9% sodium chloride injection or 5% dextrose injection were prepared in polyolefin containers. Some samples were stored at room temperature (20-25 °C); others were refrigerated (2-8 °C) for 20 hours and then stored at room temperature for up to 28 hours. The solutions were analyzed by stability-indicating high-performance liquid chromatography (HPLC) assay at specified time points over 48 hours. Solution pH was measured and containers were visually inspected at each time point. Stability was defined as retention of at least 90% of the initial tacrolimus concentration.
RESULTS
All tested solutions retained over 90% of the initial tacrolimus concentration at all time points, with the exception of the 0.001-mg/mL solution prepared in 0.9% sodium chloride injection, which was deemed unstable beyond 24 hours. At all evaluated concentrations, mean solution pH values did not change significantly over 48 hours; no particle formation was detected.
CONCLUSION
During storage in polyolefin bags at room temperature, a 0.001-mg/mL solution of tacrolimus was stable for 24 hours when prepared in 0.9% sodium chloride injection and for at least 48 hours when prepared in 5% dextrose injection. Solutions of 0.01 and 0.1 mg/mL prepared in either diluent were stable for at least 48 hours, and the 0.01-mg/mL tacrolimus solution was also found to be stable throughout a sequential temperature protocol.
Topics: Drug Packaging; Drug Stability; Drug Storage; Humans; Immunosuppressive Agents; Polyenes; Tacrolimus
PubMed: 26796907
DOI: 10.2146/ajhp150264 -
Biomolecules Apr 2020Glycogen Synthase Kinase 3 (GSK3) is an essential protein, with a relevant role in many diseases such as diabetes, cancer and neurodegenerative disorders. Particularly,...
Glycogen Synthase Kinase 3 (GSK3) is an essential protein, with a relevant role in many diseases such as diabetes, cancer and neurodegenerative disorders. Particularly, the isoform GSK3β is related to pathologies such as Alzheimer's disease (AD). This enzyme constitutes a very interesting target for the discovery and/or design of new therapeutic agents against AD due to its relation to the hyperphosphorylation of the microtubule-associated protein tau (MAPT), and therefore, its contribution to neurofibrillary tangles (NFT) formation. An in silico target profiling study identified two marine molecular families, the indole alkaloids meridianins from the tunicate genus , and lignarenones, the secondary metabolites of the shelled cephalaspidean mollusc , as possible GSK3β inhibitors. The analysis of the surface of GSK3β, aimed to find possible binding regions, and the subsequent in silico binding studies revealed that both marine molecular families can act over the ATP and/or substrate binding regions. The predicted inhibitory potential of the molecules from these two chemical families was experimentally validated in vitro by showing a ~50% of increased Ser9 phosphorylation levels of the GSK3β protein. Furthermore, we determined that molecules from both molecular families potentiate structural neuronal plasticity in vitro. These results allow us to suggest that meridianins and lignarenone B could be used as possible therapeutic candidates for the treatment of GSK3β involved pathologies, such as AD.
Topics: Adenosine Triphosphate; Animals; Binding Sites; Cell Survival; Glycogen Synthase Kinase 3 beta; Humans; Indole Alkaloids; Mice; Neurites; Neuronal Plasticity; Polyenes; Protein Kinase Inhibitors; Substrate Specificity
PubMed: 32326204
DOI: 10.3390/biom10040639 -
PloS One 2019In this study, we report antifungal activity of auroramycin against Candida albicans, Candida tropicalis, and Cryptococcus neoformans. Auroramycin, a potent...
In this study, we report antifungal activity of auroramycin against Candida albicans, Candida tropicalis, and Cryptococcus neoformans. Auroramycin, a potent antimicrobial doubly glycosylated 24-membered polyene macrolactam, was previously isolated and characterized, following CRISPR-Cas9 mediated activation of a silent polyketide synthase biosynthetic gene cluster in Streptomyces rosesporous NRRL 15998. Chemogenomic profiling of auroramycin in yeast has linked its antifungal bioactivity to vacuolar transport and membrane organization. This was verified by disruption of vacuolar structure and membrane integrity of yeast cells with auroramycin treatment. Addition of salt but not sorbitol to the medium rescued the growth of auroramycin-treated yeast cells suggesting that auroramycin causes ionic stress. Furthermore, auroramycin caused hyperpolarization of the yeast plasma membrane and displayed a synergistic interaction with cationic hygromycin. Our data strongly suggest that auroramycin inhibits yeast cells by causing leakage of cations from the cytoplasm. Thus, auroramycin's mode-of-action is distinct from known antifungal polyenes, reinforcing the importance of natural products in the discovery of new anti-infectives.
Topics: Antifungal Agents; Candida albicans; Candida tropicalis; Cations; Cryptococcus neoformans; Cytoplasm; Lactams, Macrocyclic; Polyenes; Vacuoles; Yeasts
PubMed: 31181115
DOI: 10.1371/journal.pone.0218189 -
The Journal of Biological Chemistry Apr 2009Rhodopsin is a highly specialized G protein-coupled receptor (GPCR) that is activated by the rapid photochemical isomerization of its covalently bound 11-cis-retinal...
Rhodopsin is a highly specialized G protein-coupled receptor (GPCR) that is activated by the rapid photochemical isomerization of its covalently bound 11-cis-retinal chromophore. Using two-dimensional solid-state NMR spectroscopy, we defined the position of the retinal in the active metarhodopsin II intermediate. Distance constraints were obtained between amino acids in the retinal binding site and specific (13)C-labeled sites located on the beta-ionone ring, polyene chain, and Schiff base end of the retinal. We show that the retinal C20 methyl group rotates toward the second extracellular loop (EL2), which forms a cap on the retinal binding site in the inactive receptor. Despite the trajectory of the methyl group, we observed an increase in the C20-Gly(188) (EL2) distance consistent with an increase in separation between the retinal and EL2 upon activation. NMR distance constraints showed that the beta-ionone ring moves to a position between Met(207) and Phe(208) on transmembrane helix H5. Movement of the ring toward H5 was also reflected in increased separation between the Cepsilon carbons of Lys(296) (H7) and Met(44) (H1) and between Gly(121) (H3) and the retinal C18 methyl group. Helix-helix interactions involving the H3-H5 and H4-H5 interfaces were also found to change in the formation of metarhodopsin II reflecting increased retinal-protein interactions in the region of Glu(122) (H3) and His(211) (H5). We discuss the location of the retinal in metarhodopsin II and its interaction with sequence motifs, which are highly conserved across the pharmaceutically important class A GPCR family, with respect to the mechanism of receptor activation.
Topics: Binding Sites; Cell Line; Humans; Magnetic Resonance Spectroscopy; Molecular Conformation; Polyenes; Protein Conformation; Receptors, G-Protein-Coupled; Retina; Rhodopsin; Rod Cell Outer Segment; Schiff Bases
PubMed: 19176531
DOI: 10.1074/jbc.M805725200 -
ACS Chemical Biology May 2020has emerged as a model organism for investigating the production and regulation of diverse secondary metabolites. Most of the biosynthetic gene clusters encoded in are...
has emerged as a model organism for investigating the production and regulation of diverse secondary metabolites. Most of the biosynthetic gene clusters encoded in are silent, motivating the development of new methods for accessing their products. In the current work, we add to the canon of available approaches using phenotype-guided transposon mutagenesis to characterize a silent biosynthetic gene cluster. Because secondary metabolite biosynthesis is often associated with phenotypic changes, we carried out random transposon mutagenesis followed by phenotypic inspection of the resulting colonies. Several mutants exhibited intense pigmentation and enhanced expression of an iterative type I polyketide synthase cluster that we term . Disruptions of , , and abolished the biosynthesis of the diffusible pigment, thus linking it to the operon. Isolation and structural elucidation by HR-MS and 1D/2D NMR spectroscopy revealed three novel, cryptic metabolites, thailandene A-C. Thailandenes are linear formylated or acidic polyenes containing a combination of and double bonds. Variants A and B exhibited potent antibiotic activity against and but not against . One of the transposon mutants that exhibited an enhanced expression of contained an insertion upstream of a σ54-dependent transcription factor. Closer inspection of the operon uncovered a σ54 promoter consensus sequence upstream of , providing clues regarding its regulation. Our results showcase the utility of phenotype-guided transposon mutagenesis in uncovering cryptic metabolites encoded in bacterial genomes.
Topics: Anti-Bacterial Agents; Biological Products; Burkholderia; DNA Transposable Elements; Escherichia coli; Gene Expression Regulation, Bacterial; Genome, Bacterial; Multigene Family; Mutagenesis; Phenotype; Polyenes; Polyketide Synthases; Saccharomyces cerevisiae; Secondary Metabolism; Transcription Factors
PubMed: 31816232
DOI: 10.1021/acschembio.9b00883 -
Journal of the American Chemical Society Apr 2010The first organocatalytic enantioselective radical polycyclization has been accomplished using singly occupied molecular orbital (SOMO) catalysis. The presented strategy...
The first organocatalytic enantioselective radical polycyclization has been accomplished using singly occupied molecular orbital (SOMO) catalysis. The presented strategy relies on a selective single-electron oxidation of chiral enamines formed by condensation of polyenals with an imidazolidinone catalyst employing a suitable copper(II) oxidant. The reaction proceeds under mildly acidic conditions at room temperature and shows compatibility with an array of electron-poor as well as electron-rich functional groups. Upon termination by radical arylation followed by subsequent oxidation and rearomatization, a range of polycyclic aldehydes were accessed (12 examples, 54-77% yield, 85-93% ee). The enantioselective formation of up to six new carbocycles in a single catalyst-controlled cascade is described. Evidence for a radical-based cascade mechanism is indicated by a series of experimental results.
Topics: Aldehydes; Catalysis; Cyclization; Imidazolidines; Molecular Structure; Polyenes; Stereoisomerism
PubMed: 20334384
DOI: 10.1021/ja100185p -
Applied and Environmental Microbiology Oct 2011Polyene macrolides are important antibiotics used to treat fungal infections in humans. In this work, acyltransferase (AT) domain swaps, mutagenesis, and...
Initiation of polyene macrolide biosynthesis: interplay between polyketide synthase domains and modules as revealed via domain swapping, mutagenesis, and heterologous complementation.
Polyene macrolides are important antibiotics used to treat fungal infections in humans. In this work, acyltransferase (AT) domain swaps, mutagenesis, and cross-complementation with heterologous polyketide synthase domain (PKS) loading modules were performed in order to facilitate production of new analogues of the polyene macrolide nystatin. Replacement of AT(0) in the nystatin PKS loading module NysA with the propionate-specific AT(1) from the nystatin PKS NysB, construction of hybrids between NysA and the loading module of rimocidin PKS RimA, and stepwise exchange of specific amino acids in the AT(0) domain by site-directed mutagenesis were accomplished. However, none of the NysA mutants constructed was able to initiate production of new nystatin analogues. Nevertheless, many NysA mutants and hybrids were functional, providing for different levels of nystatin biosynthesis. An interplay between certain residues in AT(0) and an active site residue in the ketosynthase (KS)-like domain of NysA in initiation of nystatin biosynthesis was revealed. Some hybrids between the NysA and RimA loading modules carrying the NysA AT(0) domain were able to prime rimocidin PKS with both acetate and butyrate units upon complementation of a rimA-deficient mutant of the rimocidin/CE-108 producer Streptomyces diastaticus. Expression of the PimS0 loading module from the pimaricin producer in the same host, however, resulted in production of CE-108 only. Taken together, these data indicate relaxed substrate specificity of NysA AT(0) domain, which is counteracted by a strict specificity of the first extender module KS domain in the nystatin PKS of Streptomyces noursei.
Topics: Acetyltransferases; Anti-Infective Agents; Chromatography, High Pressure Liquid; Genetic Complementation Test; Humans; Macrolides; Metabolic Networks and Pathways; Models, Molecular; Molecular Structure; Mutagenesis; Mutant Proteins; Polyenes; Polyketide Synthases; Recombinant Fusion Proteins; Recombination, Genetic; Streptomyces
PubMed: 21821762
DOI: 10.1128/AEM.05781-11