Tyrosine Derivatives Research Articles

Dietary L-3,4-dihydroxyphenylalanine (L-DOPA) augments cuticular melanization in Anopheles mosquitos while reducing their lifespan and malaria parasite burden.

L-3,4-dihydroxyphenylalanine (L-DOPA), a naturally occurring tyrosine derivative, is prevalent in environments that include mosquito habitats, potentially serving as part of their diet. Given its role as a precursor for melanin synthesis we investigated the effect of dietary L-DOPA on mosquito physiology and immunity to Plasmodium falciparum and Cryptococcus neoformans infection. Dietary L-DOPA was incorporated into mosquito melanin via a non-canonical pathway and had profound transcriptional effects that were associated with enhanced immunity, increased pigmentation, and reduced lifespan. Increased melanization resulted in an enhanced capacity to absorb electromagnetic radiation that affected mosquito temperatures. Bacteria in the mosquito microbiome were sources of dopamine, which is a substrate for melanization. Our results illustrate how an environmentally abundant amino acid analogue can affect mosquito physiology and suggest its potential usefulness as an environmentally friendly vector control agent to reduce malaria transmission, warranting further research and field studies.

Flumethrin exposure perturbs gut microbiota structure and intestinal metabolism in honeybees (Apis mellifera)

Flumethrin mitigates Varroa’s harm to honeybee colonies; however, its residues in colonies threaten the fitness of honeybee hosts and gut microbiota. Our previous research has shown that flumethrin induces significant physiological effects on honeybee larvae; but the effects of flumethrin on the gut microbiota and metabolism of adult honeybees are still unknown. In this study, 1-day-old honeybees were exposed to 0, 0.01, 0.1, and 1 mg/L flumethrin for 14 days and the impacts of flumethrin on the intestinal system were evaluated. The results showed that exposure to 1 mg/L flumethrin significantly reduced honeybee survival and the activities of antioxidative enzymes (superoxide dismutase and catalase) and detoxification enzymes (glutathione S-transferase) in honeybee heads. Moreover, exposure to 0.01, 0.1, and 1 mg/L flumethrin significantly decreased the diversity of the honeybee gut microbiota. Results from untargeted metabolomics showed that long-term exposure to 0.01, 0.1, and 1 mg/L flumethrin caused changes in the metabolic pathways of honeybee gut microbes. Furthermore, increased metabolism of phenylalanine, tyrosine, and tryptophan derivatives was observed in honeybee gut microbes. These findings underscore the importance of careful consideration in using pesticides in apiculture and provide a basis for safeguarding honeybees from pollutants, considering the effects on gut microbes.

Direct Alkylamination of Tyrosine Derivatives Using Fe Catalysis and O-Benzoyl-N,N-dialkylhydroxylamines

Direct Alkylamination of Tyrosine Derivatives Using Fe Catalysis and O-Benzoyl-N,N-dialkylhydroxylamines

Crafting Unnatural Peptide Macrocycles via Rh(III)-Catalyzed Carboamidation.

Contemporary developments in the field of peptide macrocyclization methodology are imperative for enabling the advance of drug design in medicinal chemistry. This report discloses a Rh(III)-catalyzed macrocyclization via carboamidation, reacting acryloyl-peptide-dioxazolone precursors and arylboronic acids to form complex cyclic peptides with concomitant incorporation of noncanonical α-amino acids. The diverse and modular technology allows for expedient access to a wide variety of cyclic peptides from 4 to 15 amino acids in size and features simultaneous formation of unnatural phenylalanine and tyrosine derivatives with up to >20:1 diastereoselectivity. The reaction showcases an expansive substrate scope with 45 examples and is compatible with the majority of standard protected amino acids used in Fmoc-solid phase peptide synthesis. The methodology is applied to the synthesis of multiple peptidomimetic macrocyclic analogs, including derivatives of cyclosomatostatin and gramicidin S.

Iron-Catalyzed C-H Alkylamination of Tyrosine Derivatives.

An efficient method for the direct alkylamination of tyrosine derivatives via iron-catalyzed C-H amination has been developed. The method, using O-benzoyl-N,N-dialkylhydroxylamines as aminating agents, provides various C-amino-functionalized tyrosine derivatives in up to 77% yield. The utility of this method is showcased by its application to the direct introduction of drug molecules into tyrosine, facilitating access to structurally diverse amino-functionalized tyrosine derivatives.

Merging Flow Synthesis and Enzymatic Maturation to Expand the Chemical Space of Lasso Peptides.

Many peptidic natural products, such as lasso peptides, cyclic peptides, and cyclotides, are conformationally constrained and show biological stability, making them attractive scaffolds for drug development. Although many peptides can be synthesized and modified through chemical methods, knot-like lasso peptides such as microcin J25 (MccJ25) and their analogues remain elusive. As the chemical space of MccJ25 analogues accessible through purely biological methods is also limited, we proposed a hybrid approach: flow-based chemical synthesis of non-natural precursor peptides, followed by in vitro transformation with recombinant maturation enzymes, to yield a more diverse array of lasso peptides. Herein, we established the rapid, flow-based synthesis of chemically modified MccJ25 precursor peptides (57 amino acids). Heterologous expression of enzymes McjB and McjC was extensively optimized to improve yields and facilitate the synthesis of multiple analogues of MccJ25, including the incorporation of non-canonical tyrosine and histidine derivatives into the lasso scaffold. Finally, using our chemoenzymatic strategy, we produced a biologically active analogue containing three d-amino acids in the loop region and incorporated backbone N-methylations. Our method provides rapid access to chemically modified lasso peptides that could be used to investigate structure-activity relationships, epitope grafting, and the improvement of therapeutic properties.

A novel eco-friendly and economical approach of bamboo colorization through biomimetic polymerization of dopamine melanin inspired by photonic microstructure of bird plumage

Bamboo is a low-carbon, sustainable, and versatile substitute for many synthetic materials, but limited variety of color restricts bamboo's decoration performance and added value. Traditional chemical colorization suffers poor generality, massive resource consumption, low colorfastness, high pollution, and remarkable damage to bamboo. This research pioneered an eco-friendly, economical approach to tailor bamboo color while keeping natural texture. Through a facile, mild modification by dopamine (a tyrosine derivative), its biomimetic polymerization endowed bamboo surface with a double-layered polydopamine melanin system mimicking morphology and composition of (keratin layer)/(melanin granules) microstructure of colorful bird plumage. Chromatic-optical and microstructural characterizations showed that polydopamine system's upper layer was nanoscale ∼ submicronscale (thickness 55∼215 nm) film bestowing on bamboo structural colors through thin-film interference. All colors at visible wavelength could be formed through controlling film thickness by adjusting dopamine concentration. Thicker film was more continuous and smoother, while thinner film was stabler. Polydopamine system's lower layer was micronscale (thickness 1.2∼4.4 μm) aggregate of particles enhancing color saturation through suppressing light scattering. Amorphous arrangement of polydopamine system made structural colors on bamboo display weak angle dependence. Physicochemical characterizations proved that bamboo featured non-covalent interaction with deposited polydopamine, which never destroyed bamboo's crystalline structure. Structural colors on bamboo exhibited satisfactory stability in long-term exposure and mechanical washing tests. Overall, proposed colorization was confirmed eco-friendly, convenient, and effective, thus contributing novel ideas to cleaner production in bamboo utilization.

A chiral metal–organic polyhedron used as stationary phase for gas chromatographic separations

Metal-organic polyhedra (MOPs), as a novel class of porous materials, exhibit distinctive application potential in molecular recognition, separation, catalysis, luminescent materials, drug delivery, and biomedicine owing to their tunable geometric shape and size, well-defined cavities, and discrete characteristics. In this study, we report that a chiral MOP [Cu12(LV)12(H2O)12] (V = L-valine) coated capillary column was used for gas chromatographic separations. The MOP coated capillary column offered the efficient separation of n-alkanes, alkylbenzenes, n-alcohols, multiple types of isomers, and enantiomers with high selectivity. Various enantiomers including esters, halogenated hydrocarbons, alcohols, ethers, aldehydes, and amino acid derivatives were well resolved on this chiral column, especially for some amino acid derivatives (e.g., Rs = 5.24 for tyrosine derivative). Compared with the commercial β-DEX 120 column for separation of the tested racemates, the chiral resolution performance of the MOP coated column can be complementary to that of β-DEX 120 column. Using 1,2-dichloropropane and o, m, p-dichlorobenzene as analytes, the MOP coated column exhibited good stability and reproducibility for gas chromatographic separations. The relative standard deviations (RSDs) of the retention time and peak area for repeated separation of 1, 2-dichloropropane and o, m, p-dichlorobenzene were less than 1.15 and 0.79 %, respectively. The results show that the chiral MOP holds great potential as a novel type of CSP for application in gas chromatography.

Impact of phenylalanine on Hanseniaspora vineae aroma metabolism during wine fermentation

Hanseniaspora vineae exhibits extraordinary positive oenological characteristics contributing to the aroma and texture of wines, especially by its ability to produce great concentrations of benzenoid and phenylpropanoid compounds compared with conventional Saccharomyces yeasts. Consequently, in practice, sequential inoculation of H. vineae and Saccharomyces cerevisiae allows to improve the aromatic quality of wines. In this work, we evaluated the impact on wine aroma produced by increasing the concentration of phenylalanine, the main amino acid precursor of phenylpropanoids and benzenoids. Fermentations were carried out using a Chardonnay grape juice containing 150 mg N/L yeast assimilable nitrogen. Fermentations were performed adding 60 mg/L of phenylalanine without any supplementary addition to the juice. Musts were inoculated sequentially using three different H. vineae strains isolated from Uruguayan vineyards and, after 96 h, S. cerevisiae was inoculated to complete the process. At the end of the fermentation, wine aromas were analysed by both gas chromatography–mass spectrometry and sensory evaluation through a panel of experts. Aromas derived from aromatic amino acids were differentially produced depending on the treatments. Sensory analysis revealed more floral character and greater aromatic complexity when compared with control fermentations without phenylalanine added. Moreover, fermentations performed in synthetic must with pure H. vineae revealed that even tyrosine can be used in absence of phenylalanine, and phenylalanine is not used by this yeast for the synthesis of tyrosine derivatives.

Influence of Microbiota-Related Metabolites Associated with Inflammation and Sepsis on the Peroxidase Activity of Cyclooxygenase in Healthy Human Monocytes and Acute Monocytic Leukemia Cells.

The human microbiota produces metabolites that can enter the bloodstream and exert systemic effects on various functions in both healthy and pathological states. We have studied the participation of microbiota-related metabolites in bacterial infection by examining their influence on the activity of cyclooxygenase (COX) as a key enzyme of inflammation. The influence of aromatic microbial metabolites, derivatives of phenylalanine (phenylpropionic acid, PPA), tyrosine (4-hydroxyphenyllactic acid, HPLA), and tryptophan (indolacetic acids, IAA), the concentrations of which in the blood change notably during sepsis, was evaluated. Also, the effect of itaconic acid (ITA) was studied, which is formed in macrophages under the action of bacterial lipopolysaccharides (LPS) and appears in the blood in the early stages of infection. Metabiotic acetyl phosphate (AcP) as a strong acetylating agent was also tested. The activity of COX was measured via the TMPD oxidation colorimetric assay using the commercial pure enzyme, cultured healthy monocytes, and the human acute monocytic leukemia cell line THP-1. All metabolites in the concentration range of 100-500 μM lowered the activity of COX. The most pronounced inhibition was observed on the commercial pure enzyme, reaching up to 40% in the presence of AcP and 20-30% in the presence of the other metabolites. On cell lysates, the effect of metabolites was preserved, although it significantly decreased, probably due to their interaction with other targets subject to redox-dependent and acetylation processes. The possible contribution of the redox-dependent action of microbial metabolites was confirmed by assessing the activity of the enzyme in the presence of thiol reagents and in model conditions, when the COX-formed peroxy intermediate was replaced with tert-butyl hydroperoxide (TBH). The data show the involvement of the microbial metabolites in the regulation of COX activity, probably due to their influence on the peroxidase activity of the enzyme.

Chemical Modification of Silk Proteins via Palladium‐Mediated Suzuki−Miyaura Reactions

AbstractSuzuki−Miyaura cross‐coupling reactions are used to modify the tyrosine residues on Bombyx mori silkworm silk proteins using a water‐soluble palladium catalyst. First, model reactions using tyrosine derivatives are screened to determine optimal reaction conditions. For these reactions, a variety of aryl boronic acids, solvents, buffers, and temperature ranges are explored. Qualitative information on the reaction progress is collected via high‐performance liquid chromatography (HPLC), mass spectrometry (MS), and nuclear magnetic resonance (NMR). Optimized reactions are then applied to silk proteins. It is demonstrated the ability to modify silk fibroin in solution by first iodinating the tyrosine residues on the protein, and then carrying out Suzuki‐Miyaura reactions with a variety of boronic acid derivatives. Modification of silk is confirmed with NMR, ion‐exchange chromatography (IEC), UV‐vis, and infrared spectroscopy (IR).

An in-depth and in vitro evaluation of the antioxidant and neuroprotective activity of aqueous and ethanolic extract of Asparagus racemosus Linn seed

The study aimed to explore the phytochemicals present in the aqueous and ethanolextracts of Asparagus racemosus Linn seeds by GC-MS and LC-MS analysis and to determine the neuro protective and antioxidant potential of both the extracts. The GC-MS and LC-MS analysis of the aqueous and ethanol seed extract indicated the presence of various chemical constituents such as ascorbic acid, hydroxycinnamic acid, fatty acids, pyroglutamic acid, pentanoic acid, decanoic acid, hexadecanoic acid, naphthalene, hydroxycinnamic acid, thiamine hydrochloride, coumaroyl putrescin, agrimol, epanorin, brevicarine, rubiadin, pyroglutamic acid, tyrosine derivative, linoleyl acetate etc. Neuroprotective effect of aqueous and ethanol extracts of Asparagus racemosus Linn seeds on SHSY5Y cell line was evaluated by MTT assay and the results showedthat ethanol extract of the plant got more neuroprotective activity on cell lines. The antioxidant results showed that both of the extracts had almost similar DPPH and ABTS radical scavenging. However, the ethanol extract had more potent antioxidant power than the aqueous extract. Study data suggest that whole plant of Asparagus racemosus Linn seeds possessed neuroprotective and anti-oxidative activities and the best neuroprotective and anti-oxidant activity being exhibited by the ethanolic extract of the plant.

Trifluoromethylthiolation of Tryptophan and Tyrosine Derivatives: A Tool for Enhancing the Local Hydrophobicity of Peptides.

The incorporation of fluorinated groups into peptides significantly affects their biophysical properties. We report herein the synthesis of Fmoc-protected trifluoromethylthiolated tyrosine (CF3S-Tyr) and tryptophan (CF3S-Trp) analogues on a gram scale (77-93% yield) and demonstrate their use as highly hydrophobic fluorinated building blocks for peptide chemistry. The developed methodology was successfully applied to the late-stage regioselective trifluoromethylthiolation of Trp residues in short peptides (66-80% yield) and the synthesis of various CF3S-analogues of biologically active monoamines. To prove the concept, Fmoc-(CF3S)Tyr and -Trp were incorporated into the endomorphin-1 chain (EM-1) and into model tripeptides by solid-phase peptide synthesis. A remarkable enhancement of the local hydrophobicity of the trifluoromethylthiolated peptides was quantified by the chromatographic hydrophobicity index determination method, demonstrating the high potential of CF3S-containing amino acids for the rational design of bioactive peptides.

An Efficient Prephenate Dehydrogenase Gene for the Biosynthesis of L-tyrosine: Gene Mining, Sequence Analysis, and Expression Optimization.

L-tyrosine is a key precursor for synthesis of various functional substances, but the microbial production of L-tyrosine faces huge challenges. The development of new microbial chassis cell and gene resource is especially important for the biosynthesis of L-tyrosine. In this study, the optimal host strain Bacillus amyloliquefaciens HZ-12 was firstly selected by detecting the production capacity of L-tyrosine. Subsequently, the recombinant expression of 15 prephenate dehydrogenase genes led to the discovery of the best gene, Bao-tyrA from B. amyloliquefaciens HZ-12. After the overexpression of Bao-tyrA, the L-tyrosine yield of the recombinant strain HZ/P43-Bao-tyrA reach 411 mg/L, increased by 42% compared with the control strain (HZ/pHY300PLK). Moreover, the nucleic acid sequence and deduced amino acid sequence of the gene Bao-tyrA were analyzed, and their conservative sites and catalytic mechanisms were proposed. Finally, the expression of Bao-tyrA was regulated through a promoter and 5'-UTR sequence to obtain the optimal expression elements. Thereby, the maximum L-tyrosine yield of 475 mg/L was obtained from HZ/P43-UTR3-Bao-tyrA. B. amyloliquefaciens was applied for the first time to produce L-tyrosine, and the optimal prephenate dehydrogenase gene Bao-tyrA and corresponding expression elements were obtained. This study provides new microbial host and gene resource for the construction of efficient L-tyrosine chassis cells, and also lays a solid foundation for the production of various functional tyrosine derivatives.

Pd‐Catalyzed Arylation and Benzylation of Tyrosine at the δ−C(sp2)−H and C(2) Positions: Expanding the Library of Unnatural Tyrosines

AbstractThis paper describes Pd(II)‐catalyzed picolinamide‐directed intermolecular arylation and benzylation of remote δ−C(sp2)−H bond (C(2) position) of the aryl ring in tyrosine derivatives and expansion of the library of unnatural tyrosine. Various racemic and enantiopure bis C(2) (ortho C−H) arylated and benzylated tyrosine derivatives were assembled in good yields. Removal of the picolinoyl moiety after the C(2)−H arylation and assembling of tyrosine‐based peptides using C(2)−H arylated tyrosines were shown. Tyrosine derivatives and biaryl amino acids are vital scaffolds in medicinal chemistry. Correspondingly, this work is a contribution towards the expansion of the unnatural tyrosine library with biaryl‐ or terphenyl and diarylmethane‐based tyrosine scaffolds.

Engineered Escherichia coli platforms for tyrosine-derivative production from phenylalanine using phenylalanine hydroxylase and tetrahydrobiopterin-regeneration system

BackgroundAromatic compounds derived from tyrosine are important and diverse chemicals that have industrial and commercial applications. Although these aromatic compounds can be obtained by extraction from natural producers, their growth is slow, and their content is low. To overcome these problems, many of them have been chemically synthesized from petroleum-based feedstocks. However, because of the environmental burden and depleting availability of feedstock, microbial cell factories are attracting much attention as sustainable and environmentally friendly processes.ResultsTo facilitate development of microbial cell factories for producing tyrosine derivatives, we developed simple and convenient tyrosine-producing Escherichia coli platforms with a bacterial phenylalanine hydroxylase, which converted phenylalanine to tyrosine with tetrahydromonapterin as a cofactor, using a synthetic biology approach. By introducing a tetrahydrobiopterin-regeneration system, the tyrosine titer of the plasmid-based engineered strain was 4.63 g/L in a medium supplemented with 5.00 g/L phenylalanine with a test tube. The strains were successfully used to produce industrially attractive compounds, such as tyrosol with a yield of 1.58 g/L by installing a tyrosol-producing module consisting of genes encoding tyrosine decarboxylase and tyramine oxidase on a plasmid. Gene integration into E. coli chromosomes has an advantage over the use of plasmids because it increases genetic stability without antibiotic feeding to the culture media and enables more flexible pathway engineering by accepting more plasmids with artificial pathway genes. Therefore, we constructed a plasmid-free tyrosine-producing platform by integrating five modules, comprising genes encoding the phenylalanine hydroxylase and tetrahydrobiopterin-regeneration system, into the chromosome. The platform strain could produce 1.04 g/L of 3,4-dihydroxyphenylalanine, a drug medicine, by installing a gene encoding tyrosine hydroxylase and the tetrahydrobiopterin-regeneration system on a plasmid. Moreover, by installing the tyrosol-producing module, tyrosol was produced with a yield of 1.28 g/L.ConclusionsWe developed novel E. coli platforms for producing tyrosine from phenylalanine at multi-gram-per-liter levels in test-tube cultivation. The platforms allowed development and evaluation of microbial cell factories installing various designed tyrosine-derivative biosynthetic pathways at multi-grams-per-liter levels in test tubes.

Synthesis of the Isodityrosine Moiety of Seongsanamide A-D and Its Derivatives.

The concise and highly convergent synthesis of the isodityrosine unit of seongsanamide A-D and its derivatives bearing a diaryl ether moiety is described. In this work, the synthetic strategy features palladium-catalyzed C(sp3)-H functionalization and a Cu/ligand-catalyzed coupling reaction. We report a practical protocol for the palladium-catalyzed mono-arylation of β-methyl C(sp3)-H of an alanine derivative bearing a 2-thiomethylaniline auxiliary. The reaction is compatible with a variety of functional groups, providing practical access to numerous β-aryl-α-amino acids; these acids can be converted into various tyrosine and dihydroxyphenylalanine (DOPA) derivatives. Then, a CuI/N,N-dimethylglycine-catalyzed arylation of the already synthesized DOPA derivatives with aryl iodides is described for the synthesis of isodityrosine derivatives.

Enzymatic oxidation of tyrosine enantiomers into biomimetic pigments with enhanced performance for hair dyeing

Most natural biomolecules have two enantiomeric forms and can exist in either of them. Despite the L-type homochirality of natural biopolymers composed of amino acids, a great deal of effort has been devoted to the systems in which chirality dictates molecular self-assembly and corresponding properties. Previously, we demonstrated that chemical pre-modification of tyrosine (L-Tyr) inspired by natural eumelanin can obtain colorful pigments and surface coatings, but their characteristics like stability still have development space. Here, the racemic reaction systems of tyrosine derivatives (L/D-Tyr, Boc-L/D-Tyr and Cbz-L/D-Tyr) were designed, and we proved that substrate molecular chirality can affect the reaction rate of the oxidation process, change the intermolecular force and arrangement during assembly, thus influencing the morphology, structures, and properties of the biomimetic pigment materials. At the same time, we found that L + D-tyrosine derivatives can be oxidized and deposited on hair surfaces to obtain the color effect of black and red-brown series, and achieve green-safe biological hair dyeing. Compared with previous studies, it has faster coloring speed, higher color saturation, stronger color fixation stability, good mechanical strength and biocompatibility, providing a new idea for the manufacture of chiral-inspired advanced materials with bio-nanotechnology applications.

Yeast: A platform for the production of L -tyrosine derivatives.

L -Tyrosine derivatives are widely applied in the pharmaceutical, food, and chemical industries. Their production is mainly confined to chemical synthesis and plant extract. Microorganisms, as cell factories, exhibit promising advantages for valuable chemical production to fulfill the increase in the demand of global markets. Yeast has been used to produce natural products owing to its robustness and genetic maneuverability. Focusing on the progress of yeast cell factories for the production of L -tyrosine derivatives, we summarized the emerging metabolic engineering approaches in building L -tyrosoine-overproducing yeast and constructing cell factories of three typical chemicals and their derivatives: tyrosol, p-coumaric acid, and L -DOPA. Finally, the challenges and opportunities of L -tyrosine derivatives production in yeast cell factories were also discussed.

De novo biosynthesis of berberine and halogenated benzylisoquinoline alkaloids in Saccharomyces cerevisiae

Berberine is an extensively used pharmaceutical benzylisoquinoline alkaloid (BIA) derived from plants. Microbial manufacturing has emerged as a promising approach to source valuable BIAs. Here, we demonstrated the complete biosynthesis of berberine in Saccharomyces cerevisiae by engineering 19 genes including 12 heterologous genes from plants and bacteria. Overexpressing bottleneck enzymes, fermentation scale-up, and heating treatment after fermentation increased berberine titer by 643-fold to 1.08 mg L-1. This pathway also showed high efficiency to incorporate halogenated tyrosine for the synthesis of unnatural BIA derivatives that have higher therapeutical potentials. We firstly demonstrate the in vivo biosynthesis of 11-fluoro-tetrahydrocolumbamine via nine enzymatic reactions. The efficiency and promiscuity of our pathway also allow for the simultaneous incorporation of two fluorine-substituted tyrosine derivatives to 8, 3’-di-fluoro-coclaurine. This work highlights the potential of yeast as a versatile microbial biosynthetic platform to strengthen current pharmaceutical supply chain and to advance drug development.