RESUMEN

Thiol dioxygenases (TDOs) are non­heme Fe(II)­dependent enzymes that catalyze the O2-dependent oxidation of thiol substrates to their corresponding sulfinic acids. Six classes of TDOs have thus far been identified and two, cysteine dioxygenase (CDO) and cysteamine dioxygenase (ADO), are found in eukaryotes. All TDOs belong to the cupin superfamily of enzymes, which share a common ß­barrel fold and two cupin motifs: G(X)5HXH(X)3-6E(X)6G and G(X)5-7PXG(X)2H(X)3N. Crystal structures of TDOs revealed that these enzymes contain a relatively rare, neutral 3­His iron­binding facial triad. Despite this shared metal-binding site, TDOs vary greatly in their secondary coordination spheres. Site­directed mutagenesis has been used extensively to explore the impact of changes in secondary sphere residues on substrate specificity and enzymatic efficiency. This chapter summarizes site-directed mutagenesis studies of eukaryotic TDOs, focusing on the tools and practicality of non­standard amino acid incorporation.

Asunto(s)

Aminoácidos , Dioxigenasas , Mutagénesis Sitio-Dirigida , Dioxigenasas/química , Dioxigenasas/metabolismo , Dioxigenasas/genética , Aminoácidos/metabolismo , Aminoácidos/química , Especificidad por Sustrato , Cisteína-Dioxigenasa/química , Cisteína-Dioxigenasa/metabolismo , Cisteína-Dioxigenasa/genética , Compuestos de Sulfhidrilo/metabolismo , Compuestos de Sulfhidrilo/química , Humanos , Animales , Modelos Moleculares

RESUMEN

The current standard method for amino acid signal identification in protein NMR spectra is sequential assignment using triple-resonance experiments. Good software and elaborate heuristics exist, but the process remains laboriously manual. Machine learning does help, but its training databases need millions of samples that cover all relevant physics and every kind of instrumental artifact. In this communication, we offer a solution to this problem. We propose polyadic decompositions to store millions of simulated three-dimensional NMR spectra, on-the-fly generation of artifacts during training, a probabilistic way to incorporate prior and posterior information, and integration with the industry standard CcpNmr software framework. The resulting neural nets take [1H,13C] slices of mixed pyruvate-labeled HNCA spectra (different CA signal shapes for different residue types) and return an amino acid probability table. In combination with primary sequence information, backbones of common proteins (GB1, MBP, and INMT) are rapidly assigned from just the HNCA spectrum.

Asunto(s)

Proteínas , Proteínas/química , Resonancia Magnética Nuclear Biomolecular/métodos , Programas Informáticos , Aminoácidos/química , Algoritmos , Isótopos/química , Aprendizaje Automático

RESUMEN

Electrospray ionization is widely used to generate vapor phase ions for analysis by mass spectrometry in proteomics research. However, only a small fraction of the analyte enters the mass spectrometer due to losses that are fundamentally linked to the use of a background gas to stimulate the generation of ions from electrosprayed droplets. Here we report a nanopore ion source that delivers ions directly into high vacuum from aqueous solutions. The ion source comprises a pulled quartz pipette with a sub-100 nm opening. Ions escape an electrified meniscus by ion evaporation and travel along collisionless trajectories to the ion detector. We measure mass spectra of 16 different amino acid ions, post-translationally modified variants of glutathione, and the peptide angiotensin II, showing that these analytes can be emitted as desolvated ions. The emitted current is composed of ions rather than charged droplets, and more than 90% of the current can be recovered in a distant collector.

Asunto(s)

Aminoácidos , Iones , Nanoporos , Péptidos , Espectrometría de Masa por Ionización de Electrospray , Vacio , Aminoácidos/química , Péptidos/química , Espectrometría de Masa por Ionización de Electrospray/métodos , Proteómica/métodos , Angiotensina II/química

RESUMEN

Hyperpolarized pyruvate is a widely used marker to track metabolism in vivo and a benchmark molecule for hyperpolarization methods. Here, we show how a combination of improved bullet-DNP instrumentation, an optimized sample preparation and a further sensitivity increase via a 13C-1H polarization transfer after dissolution enable the observation of pyruvate at a concentration of 250 nM immediately after dissolution. At this concentration, the experiment employs a total mass of pyruvate of only 20 ng or 180 pmol. If the concentration is increased to 45 µM, pyruvate may be detected 1 min after dissolution with a signal-to-noise ratio exceeding 50. The procedure can be extended to observe a mixture of amino acids at low micromolar concentrations.

Asunto(s)

Aminoácidos , Ácido Pirúvico , Aminoácidos/análisis , Aminoácidos/química , Ácido Pirúvico/química , Ácido Pirúvico/análisis , Espectroscopía de Resonancia Magnética/métodos

RESUMEN

This study aimed to investigate the effect of oxidation on fish gelatin and its emulsifying properties. Fish gelatin was oxidized with varying concentrations of H2O2 (0-30 mM). Increased concentrations of the oxidant led to a decrease in amino acids in the gelatin, including glycine, lysine, and arginine. Additionally, the relative content of ordered secondary structure and triple helix fractions decreased. Zeta potential decreased, while particle size, surface hydrophobicity, and water contact angle increased. Regarding emulsifying behavior, oxidation promoted the adsorption of gelatin to the oil-water interface and reduced interfacial tension. With increased degrees of oxidation, the zeta potential and size of the emulsion droplets decreased. The oxidized gelatin exhibited better emulsifying activity but worse emulsifying stability. Based on these results, a mechanism for how oxidation affects the emulsifying properties of gelatin was proposed: the increase in gelatin's hydrophobicity and the decrease in triple helix structure induced by oxidation reduced the interfacial tension at the oil-water interface. This promoted protein adsorption at the oil-water interface, allowing the formation of smaller oil droplets and enhancing gelatin's emulsifying activity. However, the decrease in electrostatic repulsion between emulsion droplets and the decrease in solution viscosity increased the flocculation and aggregation of oil droplets, ultimately weakening the emulsifying stability of gelatin.

Asunto(s)

Emulsiones , Proteínas de Peces , Gelatina , Interacciones Hidrofóbicas e Hidrofílicas , Oxidación-Reducción , Gelatina/química , Emulsiones/química , Animales , Proteínas de Peces/química , Tamaño de la Partícula , Peróxido de Hidrógeno/química , Viscosidad , Aminoácidos/química , Tensión Superficial , Emulsionantes/química , Peces , Adsorción , Estructura Secundaria de Proteína

RESUMEN

Microwaves have been successfully employed in the Lewis acid titanium tetrachloride-assisted synthesis of peptide systems. Dipeptide systems with their amino function differently protected with urethane protecting groups have been synthesized in short periods of time and with high yields. The formation of the peptide bond between the two reacting amino acids was achieved in pyridine by using titanium tetrachloride as a condensing agent and heating the reaction mixture with a microwave reactor. The reaction conditions are compatible with amino acids featuring various side chains and different protecting groups on both the amino function and side chains. Additionally, the substrates retain their chiral integrity after reaction.

Asunto(s)

Dipéptidos , Microondas , Titanio , Dipéptidos/química , Dipéptidos/síntesis química , Titanio/química , Aminoácidos/química , Soluciones

RESUMEN

Modern life is essentially homochiral, containing D-sugars in nucleic acid backbones and L-amino acids in proteins. Since coded proteins are theorized to have developed from a prebiotic RNA World, the homochirality of L-amino acids observed in all known life presumably resulted from chiral transfer from a homochiral D-RNA World. This transfer would have been mediated by aminoacyl-RNAs defining the genetic code. Previous work on aminoacyl transfer using tRNA mimics has suggested that aminoacylation using D-RNA may be inherently biased toward reactivity with L-amino acids, implying a deterministic path from a D-RNA World to L-proteins. Using a model system of self-aminoacylating D-ribozymes and epimerizable activated amino acid analogs, we test the chiral selectivity of 15 ribozymes derived from an exhaustive search of sequence space. All of the ribozymes exhibit detectable selectivity, and a substantial fraction react preferentially to produce the D-enantiomer of the product. Furthermore, chiral preference is conserved within sequence families. These results are consistent with the transfer of chiral information from RNA to proteins but do not support an intrinsic bias of D-RNA for L-amino acids. Different aminoacylation structures result in different directions of chiral selectivity, such that L-proteins need not emerge from a D-RNA World.

Asunto(s)

Aminoácidos , Aminoacilación , ARN Catalítico , ARN Catalítico/metabolismo , ARN Catalítico/química , ARN Catalítico/genética , Aminoácidos/química , Aminoácidos/metabolismo , Estereoisomerismo , Conformación de Ácido Nucleico , ARN/metabolismo , ARN/genética , ARN/química , Código Genético

RESUMEN

The incorporation of non-canonical amino acids (ncAAs) into the metal coordination environments of proteins has endowed metalloproteins with enhanced properties and novel activities, particularly in hemoproteins. In this work, we disclose a scalable synthetic strategy that enables the production of myoglobin (Mb) variants with non-canonical heme ligands, i.e., HoCys and f4Tyr. The ncAA-containing Mb* variants (with H64V/V68A mutations) were obtained through two consecutive native chemical ligations and a subsequent desulfurization step, with overall isolated yield up to 28.6 % in over 10-milligram scales. After refolding and heme b cofactor reconstitution, the synthetic Mb* variants showed typical electronic absorption bands. When subjected to the catalysis of the cyclopropanation of styrene, both synthetic variants, however, were not as competent as the His-ligated Mb*. We envisioned that the synthetic method reported herein would be useful for incorporating a variety of ncAAs with diverse structures and properties into Mb for varied purposes.

Asunto(s)

Hemo , Mioglobina , Mioglobina/química , Mioglobina/metabolismo , Ligandos , Hemo/química , Hemo/metabolismo , Estructura Molecular , Aminoácidos/química , Aminoácidos/metabolismo

RESUMEN

Protein-based enzymes are among the most efficient catalysts on our planet. A common feature of protein enzymes is that all catalytic amino acids occupy a limited, narrow space and face each other. In this study, we created a theoretical novel biomimetic molecule containing different multiple catalytic peptides. Although single peptides are far less catalytically efficient than protein enzymes, Octopus-arms-mimicking biomolecules containing eight different peptides (Octopuzymes) can efficiently catalyze organic reactions. Since structural information for extant protein enzymes, predicted enzymes based on genome data, and artificially designed enzymes is available for designing Octopuzymes, they could in theory mimic all protein enzyme reactions on our planet. Moreover, besides L-amino acids, peptides can contain D-amino acids, non-natural amino acids, chemically modified amino acids, nucleotides, vitamins, and manmade catalysts, leading to a huge expansion of catalytic space compared with extant protein enzymes. Once a reaction catalyzed by an Octopuzyme is defined, it could be rapidly evolvable via multiple amino acid substitutions on the eight peptides of Octopuzymes.

Asunto(s)

Péptidos , Péptidos/química , Catálisis , Aminoácidos/química , Materiales Biomiméticos/química , Materiales Biomiméticos/metabolismo

RESUMEN

The growing problem of herbicide resistance necessitates the development of novel herbicidal active ingredients, together with other integrated weed management approaches. Natural products are a major source of inspiration for novel actives. In previous research, we identified a 3-acyltetramic acid of microbial origin that inhibited algal growth in marine biofilms, at least in part through inhibition of photosystem II. In this work, we demonstrate the herbicidal effect of this lead compound and construct multiple libraries to test the impact of the different substituents of the central scaffold in order to study the structure-activity relationships. Among these analogues, the highest activities were found for medium- to long-chain acyl groups and apolar secondary amino acid residues. Finally, we provide first insights into the herbicidal mechanisms and present preliminary field-trial and ecotoxicological results for TA12-Pro, the most active analogue in our library. Together, this research shows the potential of 3-acyltetramic acids for herbicide development.

Asunto(s)

Aminoácidos , Herbicidas , Herbicidas/farmacología , Herbicidas/química , Relación Estructura-Actividad , Aminoácidos/química , Aminoácidos/farmacología , Malezas/efectos de los fármacos , Malezas/crecimiento & desarrollo , Ácido Tenuazónico/farmacología , Ácido Tenuazónico/química , Estructura Molecular

RESUMEN

In the present work, chemical and enzymatic assisted techniques were compared for protein extraction from lesser mealworm larvae (LM, Alphitobius diaperinus), recently approved as a novel food in the European Union. All extracts showed appreciable nutritional quality, with quantities of essential amino acids above the reference standard. Conventional alkali extraction allowed the isolation of only 73% of the protein, preserving the amino acid composition but potentially causing denaturation or racemisation. The "stepwise" method, following the Osborne fractionation, improved protein recovery to 91% by isolating four fractions with different solubility properties. Additionally, enzymatic hydrolysis using Bacillus licheniformis proteases was also tested, and it provided hydrolysates with an average degree of hydrolysis of 14%, making them a potential hypoallergenic solution. Overall, these findings indicate the ability to tailor the composition of LM protein to meet specific needs, offering promising prospects for the use of insect protein ingredients in various applications.

Asunto(s)

Proteínas de Insectos , Larva , Valor Nutritivo , Animales , Proteínas de Insectos/aislamiento & purificación , Proteínas de Insectos/química , Aminoácidos/análisis , Aminoácidos/química , Hidrólisis , Fraccionamiento Químico/métodos , Escarabajos/química , Escarabajos/metabolismo , Bacillus licheniformis/metabolismo

RESUMEN

Synthesis of novel unnatural amino acids (UAAs) from 4-oxo-4-phenylbut-2-enoic acid derivatives with intramolecular aza-Michael addition reaction in the presence of chlorosulfonyl isocyanate (CSI) was reported in soft conditions without any metal catalyst. Acids and base as a catalyst, and solvents effects were investigated for the synthesis of novel UAAs. This novel method provides inexpensive, practicable, and efficient approach to generate UAAs. The use of UAAs has attracted great interest in the development of therapeutic agents and drug discovery to improve their properties. In this context, in addition to the synthesis of new UAAs, their inhibition effects on important metabolic enzymes of acetylcholinesterase (AChE) and carbonic anhydrases I and II (hCA I and II) enzymes were investigated. The compound 2g showed the best inhibition for CA I and AChE enzymes, while compound 2i exhibited the best inhibition profile against CA II isoenzyme. The inhibition values of these compounds were found as 1.85 ± 0.64 for AChE, 0.53 ± 0.07 for hCA I, 0.44 ± 0.15 µM for hCA II, respectively, and they showed a stronger inhibitory property than acetazolamide (standard inhibitor for hCA I and II) and tacrine (standard inhibitor for AChE) molecules. The activity of the studied molecule against different proteins that are hCA I (PDB ID: 2CAB), hCA II (PDB ID: 5AML), and AChE (PDB ID: 1OCE) was examined. Finally, the drug properties of the studied molecule were examined by performing absorption, distribution, metabolism, excretion, and toxicity analysis.

Asunto(s)

Acetilcolinesterasa , Aminoácidos , Anhidrasa Carbónica II , Anhidrasa Carbónica I , Inhibidores de Anhidrasa Carbónica , Inhibidores de la Colinesterasa , Inhibidores de la Colinesterasa/síntesis química , Inhibidores de la Colinesterasa/química , Inhibidores de la Colinesterasa/farmacología , Inhibidores de Anhidrasa Carbónica/síntesis química , Inhibidores de Anhidrasa Carbónica/química , Inhibidores de Anhidrasa Carbónica/farmacología , Anhidrasa Carbónica I/antagonistas & inhibidores , Acetilcolinesterasa/química , Acetilcolinesterasa/metabolismo , Aminoácidos/química , Aminoácidos/síntesis química , Anhidrasa Carbónica II/antagonistas & inhibidores , Humanos , Proteínas Portadoras , Proteínas del Tejido Nervioso , Proteínas Ligadas a GPI

RESUMEN

Heteropolypeptides bearing two or more functional side chains are promising polymeric materials for various biomedical applications. However, conventional preparation of heteropolypeptides relies on the synthesis and purification of each N-carboxyanhydride (NCA) monomer in a separate manner, which substantially increases the time and cost. Herein, we report the facile preparation of heteropolypeptides with up to 86% yield within several hours, which are obtained from a mixture of crude NCA monomers. The combination of n-hexane precipitation and biphasic segregation effectively removed >90% impurities from crude NCA mixtures, allowing for the successful polymerization process. Various heteropolypeptides with monomodal distribution and narrow dispersity were efficiently prepared, whose compositions were predetermined by the feeding ratios of amino acids. We believe that this work significantly simplifies the preparation of various heteropolypeptides, boosting the downstream studies of these promising materials.

Asunto(s)

Aminoácidos , Anhídridos , Péptidos , Polimerizacion , Aminoácidos/química , Péptidos/química , Anhídridos/química , Hexanos/química

RESUMEN

In this investigation, we detail the synthesis of silver nanoparticles (AgNPs) via a precise chemical vacuum deposition (CVD) methodology, aimed at augmenting the analytical performance of laser desorption/ionization mass spectrometry (LDI-MS) for the detection of low-molecular-weight analytes. Employing a precursor supply rate of 0.0014 mg/s facilitated the formation of uniformly dispersed AgNPs, characterized by SEM and AFM to have an average diameter of 33.5 ± 1.5 nm and a surface roughness (Ra) of 11.8 nm, indicative of their homogeneous coverage and spherical morphology. XPS and SEM-EDX analyses confirmed the metallic silver composition of the nanoparticles with Ag peak splitting, reflecting the successful synthesis of metallic Ag. Comparative analytical evaluation with traditional MALDI matrices revealed that AgNPs significantly reduce signal suppression, thereby enhancing the sensitivity and specificity of LDI-MS for low-molecular-weight compounds such as triglycerides, saccharides, amino acids, and carboxylic acids. Notably, the application of AgNPs demonstrated a superior linear response for triglyceride signals with regression coefficients surpassing 0.99, markedly outperforming conventional matrices. The study further extends into quantitative analysis through nanoparticle-based laser desorption/ionization (NALDI), where AgNPs exhibited enhanced ionization efficiency, characterized by substantially lower limits of detection (LOD) and quantification (LOQ) for tested standards. Particular attention was paid to lipids with a detailed examination of their fragmentation pathways. These results highlight the significant potential of AgNPs synthesized via CVD to transform the analytical detection and quantification of low-molecular-weight compounds using NALDI. This approach offers a promising avenue for expanding the scope of analytical applications in mass spectrometry and introducing innovative methodologies for enhanced precision and sensitivity.

Asunto(s)

Nanopartículas del Metal , Plata , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Plata/química , Nanopartículas del Metal/química , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , Aminoácidos/análisis , Aminoácidos/química , Peso Molecular , Triglicéridos/análisis , Triglicéridos/química , Ácidos Carboxílicos/química , Ácidos Carboxílicos/análisis , Límite de Detección

RESUMEN

Generally, molecularly imprinted (MIP) electrochemical sensors for amino acids operate in a "label-like" mode. That is, after an amino acid is specifically recognized by an imprinted cavity at the sensing interface, the amino acid itself provides the sensing signal for quantitative detection. However, poorly electroactive amino acids impede electron transfer at the sensing interface and require high potentials to drive the reaction; thus, more interfering reactions tend to be triggered in practical applications, causing enhanced background noise in the detection. To address these issues, a "label-free" mode of the MIP sensor based on the ferrocene (Fc)/PEDOT:PSS-polypyrrole (PPy) composite was designed for the first time. The Fc/PEDOT:PSS-PPy is drop coated on the electrode surface as a substrate, and MIP polymers with specific recognition ability are immobilized on the substrate via electrostatic adsorption. As a proof of concept, l-tyrosine (l-Tyr) was selected as a model analyte and the "label-free" mode MIP/Fc/PEDOT:PSS-PPy sensor was constructed. The limit of detection (LOD) and linearity range of the MIP/Fc/PEDOT:PSS-PPy sensor were 2.31 × 10-11 M and from 100 pM to 5 mM, respectively. Compared with the label-like mode, the LOD was three orders of magnitude lower, the linear range was increased by three orders of magnitude, and the sensitivity was improved by more than four times. This work provides a universal and effective concept for MIP electrochemical sensing of amino acids.

Asunto(s)

Aminoácidos , Técnicas Electroquímicas , Compuestos Ferrosos , Metalocenos , Polímeros , Pirroles , Compuestos Ferrosos/química , Metalocenos/química , Técnicas Electroquímicas/métodos , Polímeros/química , Pirroles/química , Aminoácidos/análisis , Aminoácidos/química , Impresión Molecular , Límite de Detección , Polímeros Impresos Molecularmente/química , Electrodos

RESUMEN

Hyperspectral imaging (HSI) provides opportunity for non-destructively detecting bioactive compounds contents of tea leaves and high detection accuracy require extracting effective features from the complex hyperspectral data. In this paper, we proposed a feature wavelength refinement method called interval band selecting-competitive adaptive reweighted sampling-fusing (IBS-CARS-Fusing) to extract feature wavelengths from visible-near-infrared (VNIR) and short-wave-near-infrared (SWIR) hyperspectral images. Combined with the proposed IBS-CARS-Fusing method, a kernel ridge regression (KRR) model was established to predict the contents of bioactive compounds including chlorophyll a, chlorophyll b, carotenoids, tea polyphenols, and amino acids in Dancong tea. It was revealed that the IBS-CARS-Fusing method can improve Rp2 of KRR model for these bioactive compounds by 4.77%, 4.60%, 6.74%, 15.52%, and 13.10%, respectively, and Rp2 of the model reached high values of 0.9500, 0.9481, 0.8946, 0.8882, and 0.8622. Additionally, a leaf compound mass per area thermal map was used to visualize the spatial distribution of the compounds.

Asunto(s)

Camellia sinensis , Imágenes Hiperespectrales , Hojas de la Planta , Espectroscopía Infrarroja Corta , Té , Té/química , Hojas de la Planta/química , Camellia sinensis/química , Imágenes Hiperespectrales/métodos , Espectroscopía Infrarroja Corta/métodos , Polifenoles/análisis , Polifenoles/química , Clorofila/análisis , Clorofila/química , Extractos Vegetales/química , Carotenoides/análisis , Carotenoides/química , Aminoácidos/análisis , Aminoácidos/química

RESUMEN

Polypeptides have the same or similar backbone structures as proteins and peptides, rendering them as suitable and important biomaterials. Amino acid N-carboxyanhydrides (NCA) ring-opening polymerization has been the most efficient strategy for polypeptide preparation, with continuous advance in the design of initiators, catalysts and reaction conditions. This Perspective first summarizes the recent progress of NCA synthesis and purification. Subsequently, we focus on various initiators for NCA polymerization, catalysts for accelerating polymerization or enhancing the controllability of polymerization, and recent advances in the reaction approach of NCA polymerization. Finally, we discuss future research directions and open challenges.

Asunto(s)

Anhídridos , Péptidos , Polimerizacion , Péptidos/química , Péptidos/síntesis química , Anhídridos/química , Catálisis , Estructura Molecular , Aminoácidos/química , Aminoácidos/síntesis química

RESUMEN

Inspired by our previous work on the modification of diarylpyrimidine-typed non-nucleoside reverse transcriptase inhibitors (NNRTIs) and the reported crystallographic studies, a series of novel amino acids (analogues)-substituted thiophene[3,2-d]pyrimidine derivatives were designed and synthesized by targeting the solvent-exposed region of the NNRTI-binding pocket. The biological evaluation results showed that compound 5k was the most active inhibitor, exhibiting moderate-to-excellent potency against HIV-1 wild-type (WT) and a panel of NNRTI-resistant strains, with EC50 values ranging from 0.042 µM to 7.530 µM. Of special note, 5k exhibited the most potent activity against single-mutant strains (K103N and E138K), with EC50 values of 0.031 µM and 0.094 µM, being about 4.3-fold superior to EFV (EC50 = 0.132 µM) and 1.9-fold superior to NVP (EC50 = 0.181 µM), respectively. In addition, 5k demonstrated lower cytotoxicity (CC50 = 27.9 µM) and higher selectivity index values. The HIV-1 reverse transcriptase (RT) inhibition assay was further performed to confirm their binding target. Moreover, preliminary structure-activity relationships (SARs) and molecular docking studies were also discussed in order to provide valuable insights for further structural optimizations. In summary, 5k turned out to be a promising NNRTI lead compound for further investigations of treatments for HIV-1 infections.

Asunto(s)

Aminoácidos , Fármacos Anti-VIH , Diseño de Fármacos , Transcriptasa Inversa del VIH , VIH-1 , Pirimidinas , Inhibidores de la Transcriptasa Inversa , Tiofenos , Inhibidores de la Transcriptasa Inversa/farmacología , Inhibidores de la Transcriptasa Inversa/química , Inhibidores de la Transcriptasa Inversa/síntesis química , Transcriptasa Inversa del VIH/antagonistas & inhibidores , Transcriptasa Inversa del VIH/metabolismo , VIH-1/efectos de los fármacos , VIH-1/enzimología , Pirimidinas/farmacología , Pirimidinas/química , Pirimidinas/síntesis química , Humanos , Tiofenos/farmacología , Tiofenos/química , Tiofenos/síntesis química , Fármacos Anti-VIH/farmacología , Fármacos Anti-VIH/química , Fármacos Anti-VIH/síntesis química , Relación Estructura-Actividad , Aminoácidos/química , Simulación del Acoplamiento Molecular

RESUMEN

Despite the remarkable developments of the Ugi reaction and its variants, the use of ammonia in the Ugi reaction has long been recognized as impractical and unsuccessful. Indeed, the ammonia-Ugi reaction often requires harsh reaction conditions, such as heating and microwave irradiation, and competes with the Passerini reaction, thereby resulting in low yields. This study describes a robust and practical ammonia-Ugi reaction protocol. Using originally prepared ammonium carboxylates in trifluoroethanol, the ammonia-Ugi reaction proceeded at room temperature in high yields and showed a broad substrate scope, thus synthesizing a variety of α,α-disubstituted amino acid derivatives, including unnatural dipeptides. The reaction required no condensing agents and proceeded without racemization of the chiral stereocenter of α-amino acids. Furthermore, using this protocol, we quickly synthesized a novel dipeptide, D-Leu-Aic-NH-CH2Ph(p-F), which exhibited a potent inhibitory activity against α-chymotrypsin with a Ki value of 0.091 µM.

Asunto(s)

Aminoácidos , Amoníaco , Dipéptidos , Dipéptidos/química , Dipéptidos/síntesis química , Amoníaco/química , Aminoácidos/química , Aminoácidos/síntesis química , Ácidos Carboxílicos/química , Ácidos Carboxílicos/síntesis química , Compuestos de Amonio/química , Quimotripsina/antagonistas & inhibidores , Quimotripsina/química , Estructura Molecular , Técnicas de Química Sintética

RESUMEN

The formulation and delivery of macromolecules through the oral route pose considerable challenges due to factors such as large molecular weight, pH sensitivity, and limited formulation approaches. This challenge is compounded if the drug is poorly permeable, necessitating innovative drug delivery strategies. Vancomycin, a widely prescribed glycopeptide antibiotic, has an oral bioavailability of less than 10%, leading to predominantly intravenous administration and potential patient discomfort. This study explores the potential of the buccal route as a non-invasive, highly vascularised alternative route of administration, offering a rapid onset of action while bypassing the first-pass metabolism. In this study, vancomycin was coated with L-glutamic acid using an isothermal dry particle coater to modulate permeation through the buccal cell line, TR146. Results confirm significant impact of both amino acid concentration and dry particle coating on the rate and extent of drug permeability. With the introduction of L-glutamic acid and utilisation of the isothermal dry particle coater, vancomycin's permeation profile increased six-fold compared to the control due to the formation of drug ion-pair complex. Imaging studies showed the presence of layered micronized glutamic acid particles on the surface of dry coated vancomycin particles which confirms the role of dry coating and amino acid concentration in modulating drug permeation. Microbiology experiments in Staphylococcus aureus, minimum inhibitory concentration and biofilm disruption studies, provided confirmatory evidence of antimicrobial activity of dry coated glutamic acid-vancomycin ion pair particulate structure. This study demonstrates, for the first-time, buccal delivery of dry coated large molecule drug, vancomycin, through controlled deposition of amino acid using innovative particle coating strategy.

Asunto(s)

Antibacterianos , Vancomicina , Vancomicina/administración & dosificación , Vancomicina/farmacocinética , Humanos , Antibacterianos/administración & dosificación , Antibacterianos/farmacología , Antibacterianos/farmacocinética , Aminoácidos/química , Aminoácidos/metabolismo , Staphylococcus aureus/efectos de los fármacos , Mucosa Bucal/metabolismo , Permeabilidad/efectos de los fármacos , Sistemas de Liberación de Medicamentos/métodos , Línea Celular , Ácido Glutámico/metabolismo