Structural and mechanistic investigations on CC bond forming α-oxoamine synthase allowing L-glutamate as substrate.

Carbon‑carbon (C-C) bonds serve as the fundamental structural backbone of organic molecules. As a critical CC bond forming enzyme, α-oxoamine synthase is responsible for the synthesis of α-amino ketones by performing the condensation reaction between amino acids and acyl-CoAs. We previously identified an α-oxoamine synthase (AOS), named as Alb29, involved in albogrisin biosynthesis in Streptomyces albogriseolus MGR072.

Identification of an α-Oxoamine Synthase and a One-Pot Two-Step Enzymatic Synthesis of α-Amino Ketones.

Alb29, an α-oxoamine synthase involved in albogrisin biosynthesis in MGR072, was characterized and responsible for the incorporation of l-glutamate to acyl-coenzyme A substrates. Combined with Alb29 and Mgr36 (an acyl-coenzyme A ligase), a one-pot enzymatic system was established to synthesize seven α-amino ketones. When these α-amino ketones were fed into the knockout strain Δ, respectively, the albogrisin analogs with different side chains were observed.

Constructing Microbial Hosts for the Production of Benzoheterocyclic Derivatives.

Natural products containing benzoheterocyclic skeletons are widely found in plants and exhibit various pharmacological activities. To address the current limited availability of these compounds, we herein demonstrate the production of benzopyran, furanocoumarins, and pyranocoumarins in by employing prenyltransferases and two substrate-promiscuous enzymes, XimD and XimE. To avoid the degradation in , furanocoumarins and pyranocoumarins were also successfully produced in .

Ikarugamycin inhibits pancreatic cancer cell glycolysis by targeting hexokinase 2.

Mangrove-derived actinobacteria strains are well-known for producing novel secondary metabolites. The polycyclic tetramate macrolactam (PTM), ikarugamycin (IKA) isolated from Streptomyces xiamenensis 318, exhibits antiproliferative activities against pancreatic ductal adenocarcinoma (PDAC) in vitro. However, the protein target for bioactive IKA is unclear.

Three transcriptional regulators positively regulate the biosynthesis of polycyclic tetramate macrolactams in Streptomyces xiamenensis 318.

Polycyclic tetramate macrolactams (PTMs) are a widely distributed class of structurally complex natural products, and most of them exhibit multiple biological activities. However, the transcriptional regulators (TRs) involved in the regulation of PTM production have seldom been reported. Here, we identified three TRs, i.

Characterization and Nonenzymatic Transformation of Three Types of Alkaloids from MGR072 and Discovery of Inhibitors of Indoleamine 2,3-Dioxygenase.

The known benzonaphthyridine alkaloid, albogrisin A (), and six new compounds, including two pyrazinone stereoisomers, albogrisin B ()/B' (), together with four 4-pyrroloquinolinones, two diastereoisomers, albogrisin C ()/C' (), and their methyl esters, albogrisin D ()/D' (), were isolated from mangrove-derived MGR072. and are converted into in acidic aqueous solution but into / and / in 0.05% trifluoroacetic acid acetonitrile.

Correction to: 'Dynamical modelling of secondary metabolism and metabolic switches in 318'.

[This corrects the article DOI: 10.1098/rsos.190418.

Dynamical modelling of secondary metabolism and metabolic switches in 318.

The production of secondary metabolites, while important for bioengineering purposes, presents a paradox in itself. Though widely existing in plants and bacteria, they have no definite physiological roles. Yet in both native habitats and laboratories, their production appears robust and follows apparent metabolic switches.

A Novel AdpA Homologue Negatively Regulates Morphological Differentiation in Streptomyces xiamenensis 318.

The pleiotropic transcriptional regulator AdpA positively controls morphological differentiation and regulates secondary metabolism in most species. 318 has a linear chromosome 5.96 Mb in size.

New alkylated benzoquinones from mangrove plant with anticancer activity.

Three new alkylated benzoquinones, 2-hydroxy-5-ethoxy-3-nonyl-1,4-benzoquinone (), 5--butyl-embelin (), and 2,5-dihydroxy-6-methyl-3-pentadecyl-1,4-benzoquinone (), together with seven known analogues (-), were isolated from the stems and twigs of mangrove plant, . Their structural elucidation was achieved by spectroscopic methods, chemical exchanging experiments, and semisynthesis method. The cytotoxic activities of all the isolated compounds were evaluated by MTT assay.

Combinatory Biosynthesis of Prenylated 4-Hydroxybenzoate Derivatives by Overexpression of the Substrate-Promiscuous Prenyltransferase XimB in Engineered E. coli.

Prenylated aromatic compounds are important intermediates in the biosynthesis of bioactive molecules such as 3-chromanols from plants, ubiquinones from prokaryotes and meroterpenoids from sponges. Biosynthesis of prenylated aromatic compounds using prokaryotic microorganisms has attracted increasing attention in the field of synthetic biology. In this study, we demonstrated that the production of 3-geranyl-4-hydroxybenzoic acid (GBA) and a variety of GBA analogues was feasible in a metabolically engineered E.

Structural diversity of anti-pancreatic cancer capsimycins identified in mangrove-derived Streptomyces xiamenensis 318 and post-modification via a novel cytochrome P450 monooxygenase.

Polycyclic tetramate macrolactams (PTMs) were identified as distinct secondary metabolites of the mangrove-derived Streptomyces xiamenensis 318. Together with three known compounds-ikarugamycin (1), capsimycin (2) and capsimycin B (3)-two new compounds, capsimycin C (4) with trans-diols and capsimycin D (5) with trans-configurations at C-13/C-14, have been identified. The absolute configurations of the tert/tert-diols moiety was determined in 4 by NMR spectroscopic analysis, CD spectral comparisons and semi-synthetic method.

Towards stable kinetics of large metabolic networks: Nonequilibrium potential function approach.

While the biochemistry of metabolism in many organisms is well studied, details of the metabolic dynamics are not fully explored yet. Acquiring adequate in vivo kinetic parameters experimentally has always been an obstacle. Unless the parameters of a vast number of enzyme-catalyzed reactions happened to fall into very special ranges, a kinetic model for a large metabolic network would fail to reach a steady state.

Kinetic model of metabolic network for xiamenmycin biosynthetic optimisation.

Xiamenmycins, a series of prenylated benzopyran compounds with anti-fibrotic bioactivities, were isolated from a mangrove-derived Streptomyces xiamenensis. To fulfil the requirements of pharmaceutical investigations, a high production of xiamenmycin is needed. In this study, the authors present a kinetic metabolic model to evaluate fluxes in an engineered Streptomyces lividans with xiamenmycin-oriented genetic modification based on generic enzymatic rate equations and stability constraints.

Deciphering the streamlined genome of Streptomyces xiamenensis 318 as the producer of the anti-fibrotic drug candidate xiamenmycin.

Streptomyces xiamenensis 318, a moderate halophile isolated from a mangrove sediment, produces the anti-fibrotic compound xiamenmycin. The whole genome sequence of strain 318 was obtained through long-read single-molecule real-time (SMRT) sequencing, high-throughput Illumina HiSeq and 454 pyrosequencing technologies. The assembled genome comprises a linear chromosome as a single contig of 5,961,401-bp, which is considerably smaller than other reported complete genomes of the genus Streptomyces.

In vivo metabolism study of xiamenmycin A in mouse plasma by UPLC-QTOF-MS and LC-MS/MS.

Xiamenmycin A is an antifibrotic leading compound with a benzopyran skeleton that is isolated from mangrove-derived Streptomyces xiamenensis. As a promising small molecule for fibrotic diseases, less information is known about its metabolic characteristics in vivo. In this study, the time-course of xiamenmycin A in mouse plasma was investigated by relative quantification.

Identification of two novel anti-fibrotic benzopyran compounds produced by engineered strains derived from Streptomyces xiamenensis M1-94P that originated from deep-sea sediments.

The benzopyran compound obtained by cultivating a mangrove-derived strain, Streptomyces xiamenensis strain 318, shows multiple biological effects, including anti-fibrotic and anti-hypertrophic scar properties. To increase the diversity in the structures of the available benzopyrans, by means of biosynthesis, the strain was screened for spontaneous rifampicin resistance (Rif), and a mutated rpsL gene to confer streptomycin resistance (Str), was introduced into the S. xiamenensis strain M1-94P that originated from deep-sea sediments.

Harnessing the potential of halogenated natural product biosynthesis by mangrove-derived actinomycetes.

Mangrove-derived actinomycetes are promising sources of bioactive natural products. In this study, using homologous screening of the biosynthetic genes and anti-microorganism/tumor assaying, 163 strains of actinomycetes isolated from mangrove sediments were investigated for their potential to produce halogenated metabolites. The FADH2-dependent halogenase genes, identified in PCR-screening, were clustered in distinct clades in the phylogenetic analysis.

Xiamenmycin attenuates hypertrophic scars by suppressing local inflammation and the effects of mechanical stress.

Hypertrophic scarring is a common disease affecting millions of people around the world, but there are currently no satisfactory drugs to treat the disease. Exaggerated inflammation and mechanical stress have been shown to be two main mechanisms of excessive fibrotic diseases. Here we found that a benzopyran natural product, xiamenmycin, could significantly attenuate hypertrophic scar formation in a mechanical stretch-induced mouse model.

Identification and characterization of an anti-fibrotic benzopyran compound isolated from mangrove-derived Streptomyces xiamenensis.

An anti-fibrotic compound produced by Streptomycesn xiamenensis, found in mangrove sediments, was investigated for possible therapeutic effects against fibrosis. The compound, N-[[3,4-dihydro-3S-hydroxy-2S-methyl-2-(4'R-methyl-3'S-pentenyl)-2H-1-benzopyran-6-yl]carbonyl]-threonine (1), was isolated from crude extracts and its structure, including the absolute configuration was determined by extensive spectroscopic data analyses, Mosher's method, Marfey's reagent and quantum mechanical calculations. In terms of biological effects, this compound inhibits the proliferation of human lung fibroblasts (WI26), blocks adhesion of human acute monocytic leukemia cells (THP-1) to a monolayer of WI26 cells, and reduces the contractile capacity of WI26 cells in three-dimensional free-floating collagen gels.

A novel benzo[f][1,7]naphthyridine produced by Streptomyces albogriseolus from mangrove sediments.

Mangrove Streptomyces represent a rich source of novel bioactive compounds in medicinal research. A novel alkaloid, named 1-N-methyl-3-methylamino-[N-butanoic acid-3'-(9'-methyl-8'-propen-7'-one)-amide]-benzo[f][1,7]naphthyridine-2-one (1) was isolated from Streptomyces albogriseolus originating from mangrove sediments. The structure of compound 1 was elucidated by extensive spectroscopic data analyses and verified by the ¹³C-NMR calculation at the B3LYP/6-311+G(2d,p) level of theory.

Phenolic compounds and their anti-oxidative properties and protein kinase inhibition from the Chinese mangrove plant Laguncularia racemosa.

Phenolic compounds, named integracin D (1), (7'R, 8'S, 8S)-8-hydroxyisoguaiacin (3), (2R, 3R) pinobanksin-3-caffeoylate (5) and threo-8S-7-methoxysyringylglycerol (6), respectively, were isolated from the Chinese mangrove plant Laguncularia racemosa (L) Gaertn. f. (Combretaceae), together with 23 known phenolic metabolites.

The simultaneous separation and determination of six flavonoids and troxerutin in rat urine and chicken plasma by reversed-phase high-performance liquid chromatography with ultraviolet-visible detection.

The method of high-performance liquid chromatography (HPLC) with UV-vis detection was used and validated for the simultaneous determination of six flavonoids (puerarin, rutin, morin, luteolin, quercetin, kaempferol) and troxerutin in rat urine and chicken plasma. Chromatographic separation was performed using a VP-ODS column (150 mm x 4.6 mm, 5.