RESUMEN
Delivery of active protein especially enzyme is one of the major therapeutic challenge. Replacing or substituted invalid/improper acting protein offer fast and effective treatment of disease. Herein, we describe the synthesis and properties of biotinylated peptidomimetics consisting of oxoacid-modified 2,3, L-diaminopropionic acid residues with guanidine groups on its side chains. Electrophoretic analysis showed that the obtained compounds interact with FITC-labeled streptavidin or a streptavidin-ß-galactosidase hybrid in an efficient manner. Complexes formed by the abovementioned molecules are able to cross the cell membranes of cancer or healthy cells and show promising compatibility with live cells. Analysis of ß-galactosidase activity inside the cells revealed surprisingly high levels of active enzyme in complex-treated cells compared to controls. This observation was confirmed by immunochemical studies in which the presence of ß-galactosidase was detected in the membrane and vesicles of the cells.
Asunto(s)
beta-Alanina , beta-Galactosidasa , Humanos , beta-Alanina/análogos & derivados , beta-Alanina/química , beta-Alanina/metabolismo , beta-Galactosidasa/metabolismo , Polímeros/química , Peptidomiméticos/química , Estreptavidina/química , Estreptavidina/metabolismo , Membrana Celular/metabolismoRESUMEN
The role of thermally generated 3-aminopropionamide as an intermediate in acrylamide formation in the Maillard reaction has been well established. Herein, the effect of epicatechin on the conversion of 3-aminopropionamide into acrylamide under oxidative conditions was investigated at 160-220 °C. Epicatechin promoted acrylamide generation and 3-aminopropionamide degradation. The stable isotope-labeling technique combined with UHPLC-Orbitrap-MS/MS analysis showed adduct formation between 3-aminopropionamide and the oxidized B ring of epicatechin to form a Schiff base. This initially formed Schiff base could directly degrade to acrylamide, undergo reduction or dehydration to other intermediates, and subsequently generate acrylamide. Based on accurate mass analysis, five intermediates with intact or dehydrated C rings were tentatively identified. Furthermore, reaction pathways were proposed that were supported by the changes in the levels of adducts formed during heating. To the authors' knowledge, this study is the first to reveal pathways through which flavanols promoted the formation of acrylamide in Maillard reactions.
Asunto(s)
Acrilamida , Catequina , Reacción de Maillard , Oxidación-Reducción , Acrilamida/química , Catequina/química , Espectrometría de Masas en Tándem , Calor , beta-Alanina/química , beta-Alanina/análogos & derivados , Bases de Schiff/química , Cromatografía Líquida de Alta PresiónRESUMEN
The analysis of dietary supplements is far less regulated than pharmaceuticals, leading to potential quality issues. Considering their positive effect, many athletes consume supplements containing L-histidine and ß-alanine. A new microfluidic method for the determination of L-histidine and ß-alanine in dietary supplement formulations has been developed. For the first time, capacitively coupled contactless conductivity detection was employed for the microchip electrophoresis of amino acids in real samples. A linear relationship between detector response and concentration was observed in the range of 10-100 µmol L-1 for L-histidine (R2 = 0.9968) and ß-alanine (R2 = 0.9954), while achieved limits of detection (3 × S/N ratio) were 4.2 µmol L-1 and 5.2 µmol L-1, respectively. The accuracy of the method was confirmed using recovery experiments as well as CE-UV-VIS and HPLC-UV-VIS techniques. The developed method allows unambiguous identification of amino acids in native form without chemical derivatization and with the possibility of simultaneous analysis of amino acids with metal cations.
Asunto(s)
Suplementos Dietéticos , Conductividad Eléctrica , Electroforesis por Microchip , Histidina , beta-Alanina , Electroforesis por Microchip/métodos , Suplementos Dietéticos/análisis , beta-Alanina/análisis , beta-Alanina/química , Histidina/análisis , Histidina/química , Límite de Detección , Tecnología Química Verde/métodos , Vidrio/químicaRESUMEN
Successful delivery of plasmid DNA into the microbial cells is fundamental in recombinant DNA technology. Natural bacterial transformation is limited to only certain species due in part to the repulsive forces between negatively charged DNA and bacterial membranes. Most common method of DNA delivery into bacteria is artificial transformation through heat shock and electroporation. These methods require sophisticated instruments and tedious steps in preparation of competent cells. Transformation by conjugation is also not applicable to all plasmids. Nanoparticles have been used successfully in therapeutics for drug delivery into animal cells. They are starting to gain popularity in plant sciences as novel DNA nano carriers. Despite their promise as tool for DNA delivery, their use in microbial cell transformation has not been reported yet. Here we report the synthesis of carbon dots (CDs) from citric acid and ß-alanine and their use in DNA delivery into E. coli cells. CDs were fabricated using microwave assisted synthesis. Plasmids carrying RFP reporter and ampicillin resistance genes were transferred to bacterial cells and further confirmed using polymerase chain reaction. Our findings indicate that CDs can be used successfully for delivery of foreign DNA of up to 10 kb into E. coli. We have demonstrated the use of ß-alanine/citric acid carbon dots as nanocarriers of DNA into E. coli cells and identified their limitation in terms of the size of plasmid DNA they could carry. Use of these carbon dots is a novel method in foreign DNA delivery into bacterial cells and have a potential for the transformation of resistant organism for which there is still no reliable DNA delivery systems.
Asunto(s)
Ácido Cítrico/química , ADN , Escherichia coli/genética , Nanoestructuras/química , Plásmidos , Transformación Bacteriana , beta-Alanina/química , ADN/química , ADN/genética , Plásmidos/química , Plásmidos/genéticaRESUMEN
With the recent explosion in high-resolution protein structures, one of the next frontiers in biology is elucidating the mechanisms by which conformational rearrangements in proteins are regulated to meet the needs of cells under changing conditions. Rigorously measuring protein energetics and dynamics requires the development of new methods that can resolve structural heterogeneity and conformational distributions. We have previously developed steady-state transition metal ion fluorescence resonance energy transfer (tmFRET) approaches using a fluorescent noncanonical amino acid donor (Anap) and transition metal ion acceptor to probe conformational rearrangements in soluble and membrane proteins. Here, we show that the fluorescent noncanonical amino acid Acd has superior photophysical properties that extend its utility as a donor for tmFRET. Using maltose-binding protein (MBP) expressed in mammalian cells as a model system, we show that Acd is comparable to Anap in steady-state tmFRET experiments and that its long, single-exponential lifetime is better suited for probing conformational distributions using time-resolved FRET. These experiments reveal differences in heterogeneity in the apo and holo conformational states of MBP and produce accurate quantification of the distributions among apo and holo conformational states at subsaturating maltose concentrations. Our new approach using Acd for time-resolved tmFRET sets the stage for measuring the energetics of conformational rearrangements in soluble and membrane proteins in near-native conditions.
Asunto(s)
Cobre/química , Transferencia Resonante de Energía de Fluorescencia , Proteínas de Unión a Maltosa/metabolismo , beta-Alanina/análogos & derivados , Secuencia de Aminoácidos , Fluorometría , Células HEK293 , Humanos , Proteínas de Unión a Maltosa/química , Proteínas de Unión a Maltosa/genética , Modelos Químicos , Mutación , Conformación Proteica en Hélice alfa , Relación Estructura-Actividad , Factores de Tiempo , beta-Alanina/químicaRESUMEN
A facile solid-phase synthetic method for incorporating the imidazoline ring motif, a surrogate for a trans peptide bond, into bioactive peptides is reported. The example described is the synthesis of an imidazoline peptidomimetic analog of an insect pyrokinin neuropeptide via a cyclization reaction of an iminium salt generated from the preceding amino acid and 2,4-diaminopropanoic acid (Dap).
Asunto(s)
Imidazolinas/química , Neuropéptidos/química , Péptidos/química , beta-Alanina/análogos & derivados , Animales , Química Orgánica/métodos , Éteres/química , Hormonas de Insectos/química , Insectos , Espectroscopía de Resonancia Magnética , Polímeros/química , Propionatos/química , Técnicas de Síntesis en Fase Sólida , Solventes/química , Espectrometría de Masa por Ionización de Electrospray , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , beta-Alanina/químicaRESUMEN
Cutaneous mast cells mediate numerous skin inflammatory processes and have anatomical and functional associations with sensory afferent neurons. We reveal that epidermal nerve endings from a subset of sensory nonpeptidergic neurons expressing MrgprD are reduced by the absence of Langerhans cells. Loss of epidermal innervation or ablation of MrgprD-expressing neurons increased expression of a mast cell gene module, including the activating receptor, Mrgprb2, resulting in increased mast cell degranulation and cutaneous inflammation in multiple disease models. Agonism of MrgprD-expressing neurons reduced expression of module genes and suppressed mast cell responses. MrgprD-expressing neurons released glutamate which was increased by MrgprD agonism. Inhibiting glutamate release or glutamate receptor binding yielded hyperresponsive mast cells with a genomic state similar to that in mice lacking MrgprD-expressing neurons. These data demonstrate that MrgprD-expressing neurons suppress mast cell hyperresponsiveness and skin inflammation via glutamate release, thereby revealing an unexpected neuroimmune mechanism maintaining cutaneous immune homeostasis.
Asunto(s)
Ácido Glutámico/metabolismo , Mastocitos/metabolismo , Neuronas/metabolismo , Piel/metabolismo , Animales , Células Cultivadas , Dermatitis/metabolismo , Dermatitis/patología , Toxina Diftérica/farmacología , Modelos Animales de Enfermedad , Femenino , Cadenas beta de Integrinas/genética , Cadenas beta de Integrinas/metabolismo , Células de Langerhans/citología , Células de Langerhans/efectos de los fármacos , Células de Langerhans/metabolismo , Mastocitos/citología , Mastocitos/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Neuronas/citología , Receptores Acoplados a Proteínas G/agonistas , Receptores Acoplados a Proteínas G/deficiencia , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , Piel/patología , beta-Alanina/química , beta-Alanina/metabolismo , beta-Alanina/farmacologíaRESUMEN
The formation of peptide bonds by energetic processing of amino acids is an important step towards the formation of biologically relevant molecules. As amino acids are present in space, scenarios have been developed to identify the roots of life on Earth, either by processes occurring in outer space or on Earth itself. We study the formation of peptide bonds in single collisions of low-energy He2+ ions (α-particles) with loosely bound clusters of ß-alanine molecules at impact energies typical for solar wind. Experimental fragmentation mass spectra produced by collisions are compared with results of molecular dynamics simulations and an exhaustive exploration of potential energy surfaces. We show that peptide bonds are efficiently formed by water molecule emission, leading to the formation of up to tetrapeptide. The present results show that a plausible route to polypeptides formation in space is the collision of energetic ions with small clusters of amino acids.
Asunto(s)
Aminoácidos/química , Simulación de Dinámica Molecular , Péptidos/química , Termodinámica , beta-Alanina/química , Dipéptidos/síntesis química , Dipéptidos/química , Iones/química , Oligopéptidos/síntesis química , Oligopéptidos/química , Péptidos/síntesis química , Espectrometría de Masa por Ionización de Electrospray/métodos , Agua/químicaRESUMEN
The close synergy between peptides and nucleic acids in current biology is suggestive of a functional co-evolution between the two polymers. Here we show that cationic proto-peptides (depsipeptides and polyesters), either produced as mixtures from plausibly prebiotic dry-down reactions or synthetically prepared in pure form, can engage in direct interactions with RNA resulting in mutual stabilization. Cationic proto-peptides significantly increase the thermal stability of folded RNA structures. In turn, RNA increases the lifetime of a depsipeptide by >30-fold. Proto-peptides containing the proteinaceous amino acids Lys, Arg, or His adjacent to backbone ester bonds generally promote RNA duplex thermal stability to a greater magnitude than do analogous sequences containing non-proteinaceous residues. Our findings support a model in which tightly-intertwined biological dependencies of RNA and protein reflect a long co-evolutionary history that began with rudimentary, mutually-stabilizing interactions at early stages of polypeptide and nucleic acid co-existence.
Asunto(s)
Evolución Molecular , Péptidos/metabolismo , Pliegue de Proteína , Estabilidad del ARN , ARN/metabolismo , Secuencia de Aminoácidos , Aminobutiratos/química , Aminobutiratos/metabolismo , Cationes/química , Cationes/metabolismo , Dicroismo Circular , Hidrólisis , Resonancia Magnética Nuclear Biomolecular , Origen de la Vida , Ornitina/química , Ornitina/metabolismo , Péptidos/química , Estabilidad Proteica , ARN/química , beta-Alanina/análogos & derivados , beta-Alanina/química , beta-Alanina/metabolismoRESUMEN
In diagnostic microbiology, culture media are widely used for detection of pathogenic bacteria. Such media employ various ingredients to optimize detection of specific pathogens such as chromogenic enzyme substrates and selective inhibitors to reduce the presence of commensal bacteria. Despite this, it is rarely possible to inhibit the growth of all commensal bacteria, and thus pathogens can be overgrown and remain undetected. One approach to attempt to remedy this is the use of "suicide substrates" that can target specific bacterial enzymes and selectively inhibit unwanted bacterial species. With the purpose of identifying novel selective inhibitors, six novel phosphonopeptide derivatives based on d/l-fosfalin and ß-chloro-l-alanine were synthesized and tested on 19 different strains of clinically relevant bacteria. Several compounds show potential as useful selective agents that could be exploited in the recovery of several bacterial pathogens including Salmonella, Pseudomonas aeruginosa, and Listeria.
Asunto(s)
Antiinfecciosos/síntesis química , Antiinfecciosos/farmacología , Fosfopéptidos/síntesis química , Fosfopéptidos/farmacología , Bacterias/efectos de los fármacos , Técnicas de Química Sintética , Pruebas de Sensibilidad Microbiana , Estructura Molecular , beta-Alanina/análogos & derivados , beta-Alanina/químicaRESUMEN
The traditional photodynamic therapy (PDT) using a photosensitizer and oxygen under light generates reactive oxygen species (ROS) to kill tumor cells. However, its treatment efficiency is limited by insufficient oxygen in tumor cells. Herein, ß-alanine modified gadofullerene nanoparticles (GFNPs) were explored to disrupt tumor vasculatures assisted by light for potent melanoma treatment. As tumor vasculatures are oxygen-rich, the yields of photo-induced singlet oxygen (1O2) by GFNPs are not subjected to the hypoxemia of tumor tissues. Different from the small molecule photosensitizer Chlorin e6 (Ce6), GFNPs realize high-efficiency tumor vascular disruption under light observed by using the mice tumor vascular dorsal skin fold chamber (DSFC) model. The tumor vascular disruption efficiency of GFNPs is size-dependent, and the smallest one (hydration diameter of ca. 126 nm) is more efficient. Mechanistically, the high yields of photo-induced 1O2 by GFNPs can lead to the destruction of the tumor vascular endothelial adherent junction protein-VE cadherin and the decrease of tumor vascular endothelial cells-CD31 proteins, inducing rapid tumor necrosis. In conclusion, our work provides an insight into the design of well-sized nanoparticles to powerfully treat melanoma assisted by light, as well as greatly extending the applications of PDT for robust tumor therapy.
Asunto(s)
Fulerenos/farmacología , Luz , Melanoma/tratamiento farmacológico , Nanopartículas/química , Fotoquimioterapia , Fármacos Fotosensibilizantes/farmacología , Neoplasias Cutáneas/tratamiento farmacológico , Animales , Muerte Celular/efectos de los fármacos , Clorofilidas , Femenino , Fulerenos/química , Melanoma/patología , Ratones , Ratones Endogámicos BALB C , Ratones Desnudos , Tamaño de la Partícula , Fármacos Fotosensibilizantes/síntesis química , Fármacos Fotosensibilizantes/química , Porfirinas/química , Porfirinas/farmacología , Oxígeno Singlete/análisis , Neoplasias Cutáneas/patología , Propiedades de Superficie , beta-Alanina/químicaRESUMEN
Enzyme design and engineering strategies rely almost exclusively on nature's alphabet of twenty canonical amino acids. Recent years have seen the emergence of powerful genetic code expansion methods that allow hundreds of structurally diverse amino acids to be installed into proteins in a site-selective manner. Here, we will highlight how the availability of an expanded alphabet of amino acids has opened new avenues in enzyme engineering research. Genetically encoded noncanonical amino acids have provided new tools to probe complex enzyme mechanisms, improve biocatalyst activity and stability, and most ambitiously to design enzymes with new catalytic mechanisms that would be difficult to access within the constraints of the genetic code. We anticipate that the studies highlighted in this article, coupled with the continuing advancements in genetic code expansion technology, will promote the widespread use of noncanonical amino acids in biocatalysis research in the coming years.
Asunto(s)
Aminoácidos/química , Enzimas/química , Enzimas/metabolismo , Secuencia de Aminoácidos , Aminoacil-ARNt Sintetasas/metabolismo , Biocatálisis , Dominio Catalítico , Compuestos de Diazonio/química , Código Genético , Conformación Molecular , Oxidación-Reducción , Procesos Fotoquímicos , Ingeniería de Proteínas , beta-Alanina/análogos & derivados , beta-Alanina/químicaRESUMEN
In the present study, a pyridoxal-5'-phosphate (PLP)-dependent L-aspartate-α-decarboxylase from Tribolium castaneum (TcPanD) was selected for protein engineering to efficiently produce ß-alanine. A mutant TcPanD-R98H/K305S with a 2.45-fold higher activity than the wide type was selected through error-prone PCR, site-saturation mutagenesis, and 96-well plate screening technologies. The characterization of purified enzyme TcPanD-R98H/K305S showed that the optimal cofactor PLP concentration, temperature, and pH were 0.04% (m/v), 50 °C, and 7.0, respectively. The 1mM of Na+, Ni2+, Co2+, K+, and Ca2+ stimulated the activity of TcPanD-R98H/K305S, while only 5 mM of Ni2+ and Na+ could increase its activity. The kinetic analysis indicated that TcPanD-R98H/K305S had a higher substrate affinity and enzymatic reaction rate than the wild enzyme. A total of 267 g/L substrate l-aspartic acid was consumed and 170.5 g/L of ß-alanine with a molar conversion of 95.5% was obtained under the optimal condition and 5-L reactor fermentation.
Asunto(s)
Glutamato Descarboxilasa/genética , Ingeniería de Proteínas/métodos , Fosfato de Piridoxal/metabolismo , beta-Alanina/biosíntesis , Animales , Escherichia coli/genética , Glutamato Descarboxilasa/química , Cinética , Fosfato de Piridoxal/química , Tribolium/enzimología , Tribolium/genética , beta-Alanina/químicaRESUMEN
Natural deep eutectic solvents (NADES) are a type of ionic liquid (IL) or deep eutectic solvent (DES), the ingredients of which are exclusively natural products (non-toxic and environmentally friendly). Here, we explore the potential of NADES as an alternative to conventional organic solvents (e.g., aqueous methanol or ethanol) for the extraction of flavonoids from Scutellaria baicalensis stem bark to investigate their extractability depending on structural variation. Four NADES, each containing citric acid in combination with ß-alanine, glucose, xylitol, or proline (at a molar ratio of 1:1), and a variable amount of water, were used to extract the flavonoid aglycones: baicalein (1), scutellarein (3), wogonin (5), and oroxylin A (7), and their glycosides, baicalin (2), scutellarin (4), wogonoside (6) and oroxyloside (8) from the powdered bark of S. baicalensis. The chemical profile and yield of the extracts were determined using HPTLC and HPLC. The extractability of individual flavonoids was found to be influenced by the concentration of water (20-60%, w/w) in the NADES. Among the tested flavonoids, the extraction yield of baicalein (1), scutellarein (3), wogonin (5), oroxylin A (7) with NADES was 2 to 6 times that of aqueous methanol. However, the amount of their corresponding glycosides (baicalin (2), wogonoside (6) and oroxyloside (8)) extracted with NADES was only 1.5-1.8 times higher than with aqueous methanol. Interestingly, the more hydrophilic glycosides were less extracted than their corresponding aglycones despite the high hydrophilicity of the NADES. These results prove that NADES may be used for extraction of compounds with a wide range of hydrophilicity.
Asunto(s)
Ácido Cítrico/química , Flavonoides/análisis , Scutellaria baicalensis/química , Solventes/química , Agua/química , Cromatografía Líquida de Alta Presión , Cromatografía en Capa Delgada , Glucosa/química , Interacciones Hidrofóbicas e Hidrofílicas , Estructura Molecular , Extractos Vegetales/química , Prolina/química , Xilitol/química , beta-Alanina/químicaRESUMEN
Metal-Organic Frameworks (MOFs) are porous coordination networks assembled through metal complexes with organic linkers. Due to their chemical versatility, these materials are being investigated for various applications including gas storage and separation, biomedicine and catalysis. The aim of this work is the encapsulation of the model ß-alanine amino-acid in the nanostructured zirconium-based MOF (UiO-66) which contains the ligand H2BDC (1,4-benzenedicaboxylic acid). Additionally, ligand functionalization (by using H2doBDC (2,5-dihydroxy-1,4-benzenedicarboxylic acid) and defect engineering have been carried out to produce UiO-66 derivatives, in order to modify the host-guest interactions, and hence study their influence on the ß-alanine loading capacity and release kinetics. The as-obtained materials have been characterized by X-ray diffraction (XRD), X-ray thermo diffraction (TDX), infrared (IR) spectroscopy, thermogravimetric analysis-differential scanning calorimetry (TG-DSC) and elemental analysis (EA). Morphology of nanoscale MOFs has been explored by transition electron microscopy (TEM). Adsorption isotherms have been constructed, and the concentration of ß-alanine in the post-adsorption solution (supernatant) has been quantified by high performance liquid chromatography coupled with mass spectroscopy (HPLC-MS) and EA. Adsorption capacity values indicate that the presence of hydroxyl groups at the organic linker H2doBDC enhances the host-guess affinity between the framework and the adsorbate ß-alanine. The influence of defect engineering, on the adsorption however, is not that obvious. On the other hand, desorption experiments show similar behaviour for H2doBDC-based derivatives. An adsorption mechanism has been proposed consisting of a combination of host-guest interaction at low concentrations, and covalent anchoring/ligand displacement by ß-alanine at the inorganic clusters.
Asunto(s)
Estructuras Metalorgánicas/química , Estructuras Metalorgánicas/síntesis química , Circonio/química , beta-Alanina/química , CatálisisRESUMEN
In a more synthetical approach to the study of ion-specific phenomena, four dipodal bis(guanidinium) siloxanes have been synthesized starting from glycine, ß-alanine, γ-aminobutanoic acid, L-proline and 1,3-bis(3-aminopropyl)tetramethyldisiloxane. Together with their non-amide progenitor they were comparatively studied in regards to their interactions with nine different anions: sulphate, chromate, molybdate, benzoate, chloride, azide, nitrite, nitrate and thiocyanate. Their aqueous solubilities, form, 1H NMR and FT-IR spectra were examined while searching for anion-specific interactions falling in- or outside of the Hofmeister series. We show that although the "chao-" and "kosmotropic" ions affect the properties of solutions in a predictable way, more selective cation-anion pairing is responsible for phase separation and crystallinity. As a prominent example, crystal structure of one of the benzoate salts was successfully obtained and reveals a synergy of hydrophobic packing, ionic and hydrogen bonding. Immobilized but still flexible siloxane bridges give rise to crystals described by P 42/n space group and neatly segregated into hydro- and lipophilic sections.
Asunto(s)
Aminoácidos/química , Guanidina/síntesis química , Iones/química , Silanos/síntesis química , Aniones/química , Ácido Butírico/química , Cristalización , Glicina/química , Guanidina/química , Enlace de Hidrógeno , Interacciones Hidrofóbicas e Hidrofílicas , Prolina/química , Silanos/química , Solubilidad , Soluciones , Relación Estructura-Actividad , Agua , beta-Alanina/químicaRESUMEN
Supramolecular gel material built from low-molecular-weight (LMW) gelators finds potential applications in various fields, especially in drug delivery, cell encapsulation and delivery, and tissue engineering. The majority of the LMW gelators in these applications are based on functionalized peptides/amino acids consisting of proteinogenic amino acids which are proteolytically unstable. Herein, we have developed a new LMW gelator containing non-proteinogenic amino acid namely 2,3-diaminopropionic acid (Dap), a key precursor in the synthesis of many antibiotics namely viomycin and capreomycin, by functionalizing with fluorenylmethoxycarbonyl at both amino terminals of Dap [Fm-Dap(Fm)]. Hydrogelation test at different pH indicates that Fm-Dap(Fm) can form a hydrogel in a wide range of pH (4.9 to 9.1) with minimum hydrogelation concentration depends on the pH. The mechanical strength and thermal stability of the Fm-Dap(Fm) hydrogel material are found to decrease with increasing pH (acidicâ¯>â¯neural/physiologicalâ¯>â¯basic). The thermal stability of Fm-Dap(Fm) hydrogels is pH-dependent and elicits high stability at acidic pH. Also, Fm-Dap(Fm) hydrogels exhibit strong thixotropic property where regelation (self-healing) occurs upon release of stress. Morphological analysis indicates the formation of fibrils, which are entangled to form three dimensional network structures. Several spectroscopic measurements provided evidence for the self-assembly of Fm-Dap(Fm) molecules through intermolecular aromatic π-π stacking and hydrogen bonding interactions during hydrogelation. Interestingly, Fm-Dap(Fm) not only exhibits hydrogel formation but also shows cell viability and enhanced cell proliferation at physiological pH (7.4). Further, Fm-Dap(Fm) forms a hydrogel upon co-incubation with vitamin B12 and also exhibits release of vitamin B12 over a period. The current study thus demonstrates the development of a new hydrogel material, based on LMW gelator containing the non-proteinogenic amino acid, which can elicit cell viability, enhanced cell proliferation, drug encapsulation, and drug release properties. Hence, Fm-Dap(Fm) hydrogel could be an ideal material for biomedical applications, especially in tissue engineering and drug delivery.
Asunto(s)
Aminoácidos/química , Proliferación Celular/efectos de los fármacos , Sistemas de Liberación de Medicamentos , Liberación de Fármacos , Hidrogeles/química , Vitamina B 12/farmacología , beta-Alanina/análogos & derivados , Animales , Concentración de Iones de Hidrógeno , Ratones , Modelos Moleculares , Células 3T3 NIH , Vitamina B 12/química , beta-Alanina/químicaRESUMEN
In the study presented herein, we explore the ability of copper complexes with coordinated pyridine-2-carboxaldehyde (pyca) or 2-acetylpyridine (acepy) ligands to promote the addition of amines (Schiff condensation) and other nucleophiles such as alcohols (hemiacetal formation). Distinct reactivity patterns are observed: unlike pyca complexes, acepy copper complexes can promote self-aldol addition. The introduction of a flexible chain via Schiff condensation with ß-alanine allows the possibility of chelate ring ring-opening processes mediated by pH. Further derivatization of the complex [CuCl(py-2-C(H)[double bond, length as m-dash]NCH2CH2COO)] is possible by replacing its chloride ligand with different pseudohalogens (N3-, NCO- and NCS-). In addition to the change in their magnetism, which correlates with their solid-state structures, more unexpected effects in their cytotoxicity and relaxitivities are observed, which determines their possibility to be used as MRI contrast agents. The replacement of a chloride by another pseudohalogen, although a simple strategy, can be used to critically change the cytotoxicity of the Schiff base copper(ii) complex and its selectivity towards specific cell lines.
Asunto(s)
Complejos de Coordinación/química , Complejos de Coordinación/toxicidad , Cobre/química , Cobre/toxicidad , Animales , Células CHO , Línea Celular , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Complejos de Coordinación/síntesis química , Cricetulus , Relación Dosis-Respuesta a Droga , Humanos , Cetonas/química , Cetonas/farmacología , Ligandos , Modelos Moleculares , Estructura Molecular , Piridinas/química , Piridinas/farmacología , Relación Estructura-Actividad , beta-Alanina/química , beta-Alanina/farmacologíaRESUMEN
Tripodal nonameric mannoside glycodendrimer 1 with carbohydrate tethered triazole linked with the TRIS-glycine-ß-alanine dipeptidic aromatic centered core was synthesized. Glycodendrimer 1 demonstrated potential in vitro anti-leishmanial activity. The bio-activity data was substantiated with molecular modelling and docking studies of 1 with the three-dimensional protein structure of Leishmanolysin.
Asunto(s)
Dipéptidos/síntesis química , Dipéptidos/farmacología , Glicina/química , Leishmania/efectos de los fármacos , Manósidos/química , Triazoles/química , beta-Alanina/química , Antiprotozoarios/síntesis química , Antiprotozoarios/química , Antiprotozoarios/metabolismo , Antiprotozoarios/farmacología , Técnicas de Química Sintética , Dendrímeros/química , Dipéptidos/química , Dipéptidos/metabolismo , Metaloendopeptidasas/química , Metaloendopeptidasas/metabolismo , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Conformación ProteicaRESUMEN
Numerous long-standing questions in origins-of-life research center on the history of biopolymers. For example, how and why did nature select the polypeptide backbone and proteinaceous side chains? Depsipeptides, containing both ester and amide linkages, have been proposed as ancestors of polypeptides. In this paper, we investigate cationic depsipeptides that form under mild dry-down reactions. We compare the oligomerization of various cationic amino acids, including the cationic proteinaceous amino acids (lysine, Lys; arginine, Arg; and histidine, His), along with nonproteinaceous analogs of Lys harboring fewer methylene groups in their side chains. These analogs, which have been discussed as potential prebiotic alternatives to Lys, are ornithine, 2,4-diaminobutyric acid, and 2,3-diaminopropionic acid (Orn, Dab, and Dpr). We observe that the proteinaceous amino acids condense more extensively than these nonproteinaceous amino acids. Orn and Dab readily cyclize into lactams, while Dab and Dpr condense less efficiently. Furthermore, the proteinaceous amino acids exhibit more selective oligomerization through their α-amines relative to their side-chain groups. This selectivity results in predominantly linear depsipeptides in which the amino acids are α-amine-linked, analogous to today's proteins. These results suggest a chemical basis for the selection of Lys, Arg, and His over other cationic amino acids for incorporation into proto-proteins on the early Earth. Given that electrostatics are key elements of protein-RNA and protein-DNA interactions in extant life, we hypothesize that cationic side chains incorporated into proto-peptides, as reported in this study, served in a variety of functions with ancestral nucleic acid polymers in the early stages of life.