Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 29
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Int J Biol Macromol ; 255: 127919, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37944737

RESUMO

The high water content and biocompatibility of amino-acid-based supramolecular hydrogels have generated growing interest in drug delivery research. Nevertheless, the existing dominant approach of constructing such hydrogels, the exploitation of a single amino acid type, typically comes with several drawbacks such as weak mechanical properties and long gelation times, hindering their applications. Here, we design a near-infrared (NIR) light-responsive double network (DN) structure, containing amino acids and different synthetic or natural polymers, i.e., polyacrylamide, poly(N-isopropylacrylamide), agarose, or low-gelling agarose. The hydrogels displayed high mechanical strength and high drug-loading capacity. Adjusting the ratio of Fmoc-Tyr-OH/Fmoc-Tyr(Bzl)-OH or Fmoc-Phe-OH/Fmoc-Tyr(Bzl)-OH, we could drastically shorten the gelation time of the DN hydrogels at room and body temperatures. Moreover, introducing photothermal agents (graphene oxide, carbon nanotubes, molybdenum disulfide nanosheets, or indocyanine green), we equipped the hydrogels with NIR responsivity. We demonstrated the light-triggered release of the drug baclofen, which is used in severe spasticity treatment. Rheology and stability tests confirmed the positive impact of the polymers on the mechanical strength of the hydrogels, while maintaining good stability under physiological conditions. Overall, our study contributed a novel hydrogel formulation with high mechanical resistance, rapid gel formation, and efficient NIR-controlled drug release, offering new opportunities for biomedical applications.


Assuntos
Aminoácidos , Nanotubos de Carbono , Aminoácidos/química , Sefarose/química , Liberação Controlada de Fármacos , Hidrogéis/química , Polímeros
2.
Int J Mol Sci ; 24(17)2023 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-37686165

RESUMO

There is a growing interest for complex in vitro environments that closely mimic the extracellular matrix and allow cells to grow in microenvironments that are closer to the one in vivo. Protein-based matrices and especially hydrogels can answer this need, thanks to their similarity with the cell microenvironment and their ease of customization. In this study, an experimental design was conducted to study the influence of synthesis parameters on the physical properties of gelatin methacryloyl (GelMA). Temperature, ratio of methacrylic anhydride over gelatin, rate of addition, and stirring speed of the reaction were studied using a Doehlert matrix. Their impact on the following parameters was analyzed: degree of substitution, mass swelling ratio, storage modulus (log(G')), and compression modulus. This study highlights that the most impactful parameter was the ratio of methacrylic anhydride over gelatin. Although, temperature affected the degree of substitution, and methacrylic anhydride addition flow rate impacted the gel's physical properties, namely, its storage modulus and compression modulus. Moreover, this experimental design proposed a theoretical model that described the variation of GelMA's physical characteristics as a function of synthesis conditions.


Assuntos
Gastrópodes , Hidrogéis , Animais , Projetos de Pesquisa , Gelatina , Anidridos
3.
RSC Adv ; 13(15): 10051-10067, 2023 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-37006376

RESUMO

The current study presents for the first time the synthesis of a new 2:1-[α/aza]-pseudopeptide series possessing charged amino acids (i.e., lysine) and aims at studying the influences of chirality, backbone length, and the nature of the lysine side chains on the conformation of the 2:1-[α/aza]-oligomers in solution using NMR, FTIR spectroscopy and molecular dynamic calculations. The spectroscopic results emphasized the conservation of the ß-turn conformation adopted by the trimers regardless of the chirality which demonstrated a noticeable effect on the conformation of homochiral hexamer (8c) compared with the hetero-analogue (8d). The molecular dynamic calculations predicted that the chirality and the side chain of the lysine residues caused a little distortion from the classical ß-turn conformation in the case of short trimer sequences (7c and 7d), while the chirality and the backbone length exerted more distortion on the ß-turn adopted by the longer hexamer sequences (8c and 8d). The large disturbance in hexamers from classical ß-turn was attributed to increasing the flexibility and the possibility of molecules to adopt a more energetically favorable conformation stabilized by non-classical ß-turn intramolecular hydrogen bonds. Thus, alternating d- and l-lysine amino acids in the 2:1-[α/aza]-hexamer (8d) decreases the high steric hindrance between the lysine side chains, as in the homo analogue (8c), and the distortion is less recognized. Finally, short sequences of aza-pseudopeptides containing lysine residues improve CO2 separation when used as additives in Pebax® 1074 membranes. The best membrane performances were obtained with a pseudopeptidic dimer as an additive (6b'; deprotected lysine side chain), with an increase in both ideal selectivity α CO2/N2 (from 42.8 to 47.6) and CO2 permeability (from 132 to 148 Barrer) compared to the virgin Pebax® 1074 membrane.

4.
Food Chem ; 405(Pt A): 134788, 2023 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-36370575

RESUMO

Soy and pea proteins are two rich sources of essential amino acids. The hydrolysis of these proteins reveals functional and bioactive properties of the produced small peptide mixtures. In our study, we employed the hydrolysis of soy and pea protein isolates with the endopeptidases Alcalase® and Protamex®, used alone or followed by the exopeptidase Flavourzyme®. The sequential enzyme treatments were the most efficient regarding the degree of hydrolysis. Then, soy and pea protein hydrolysates (SPHs and PPHs, respectively) were ultrafiltrated in order to select peptides of molecular weight ≤ 1 kDa. Whatever the protein source or the hydrolysis treatment, the hydrolysates showed similar molecular weight distributions and amino acid compositions. In addition, all the ultrafiltrated hydrolysates possess metal-chelating activities, as determined by UV-spectrophotometry and Surface Plasmon Resonance (SPR). However, the SPR data revealed better chelating affinities in SPHs and PPHs when produced by sequential enzymatic treatment.


Assuntos
Pisum sativum , Hidrolisados de Proteína , Hidrolisados de Proteína/química , Pisum sativum/metabolismo , Subtilisinas/metabolismo , Hidrólise , Quelantes , Peptídeos/química , Antioxidantes
5.
J Phys Chem B ; 126(37): 7159-7165, 2022 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-36099394

RESUMO

The electric field gradient tensor (considered here at the level of a nitrogen nucleus) can be described by two parameters: the largest element in the (X,Y,Z) principal axis system, denoted by VZZ (leading to the nuclear quadrupole coupling), and the asymmetry parameter η = (|VYY| - |VXX|)/|VZZ| with |VZZ| > |VYY| > |VXX|. The frequencies of the three nitrogen-14 nuclear quadrupole resonance (NQR) transitions depend on both parameters but, for sensitivity reasons, their determination may be especially difficult and time consuming. For a partly rigid NH grouping with a labile proton, water nuclear magnetic resonance (NMR) relaxometry curves may exhibit these three transitions (dubbed quadrupolar dips or quadrupole relaxation enhancement (QRE)), provided that the NH grouping belongs to a moiety possessing a sufficient degree of ordering. Their line shape leads to the correlation time describing mainly the motion of the NH grouping (the proton of which being in exchange with water protons), and their amplitude can be interpreted in terms of an effective NH distance. This approach is applied to a hydrogel, where separate NQR lines are observed for the different types of water existing in this system. Furthermore, the analysis of experimental data allows one to determine the nuclear quadrupole coupling in the protonated and deprotonated forms of this molecular moiety involving a labile NH grouping.


Assuntos
Prótons , Água , Hidrogéis , Espectroscopia de Ressonância Magnética , Nitrogênio/química
6.
Nanoscale ; 14(13): 4908-4921, 2022 Mar 31.
Artigo em Inglês | MEDLINE | ID: mdl-35319034

RESUMO

Over the last twenty years, low-molecular weight gelators and, in particular, peptide-based hydrogels, have drawn great attention from scientists thanks to both their inherent advantages in terms of properties and their high modularity (e.g., number and nature of the amino acids). These supramolecular hydrogels originate from specific peptide self-assembly processes that can be driven, modulated and optimized via specific chemical modifications brought to the peptide sequence. Among them, the incorporation of nucleobases, another class of biomolecules well-known for their abilities to self-assemble, has recently appeared as a new promising and burgeoning approach to finely design supramolecular hydrogels. In this minireview, we would like to highlight the interest, high potential, applications and perspectives of these innovative and emerging low-molecular weight nucleopeptide-based hydrogels.


Assuntos
Hidrogéis , Peptídeos , Sequência de Aminoácidos , Aminoácidos/química , Hidrogéis/química , Peso Molecular , Peptídeos/química
7.
Inorg Chem ; 61(4): 1941-1948, 2022 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-35034436

RESUMO

Antioxidant compounds are chemicals of primary importance, especially for their applications in nutrition and healthcare, thanks to their abilities to prevent oxidation processes and to limit and/or rebalance the oxidative stress, well-known for its impact on a wide variety of diseases. While several biomolecules are well-known for their antioxidant properties (e.g., ascorbic acid, carotenoids, phenolic derivatives), bio-sourced antioxidants have drawn considerable attention in the last decades, especially bioactive peptides, mainly obtained by the hydrolysis process. Antioxidant peptide sequences are mainly identified a posteriori, thanks to fastidious and time-consuming approaches and techniques, limiting the discovery of new efficient peptides. In this context and taking inspiration from nature, we report herein on a new series of three bio-inspired antioxidant peptides derived from the milk protein casein. These phosphopeptides, designed to chelate the redox-active iron(III) and forming highly soluble complexes up to pH 9, act both as indirect (i.e., inhibition of the metal redox activity) and direct (i.e., radical scavenging) antioxidants.


Assuntos
Antioxidantes
8.
J Agric Food Chem ; 69(31): 8819-8827, 2021 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-34324321

RESUMO

Metal-chelating peptides (MCP) are considered as indirect antioxidants due to their capacity to inhibit radical chain reaction and oxidation. Here, we propose a new proof of concept for the screening of MCPs present in protein hydrolysates for valorizing their antioxidant properties by using the emerging time-resolved molecular dynamics technology, switchSENSE. This method unveils possible interactions between MCPs and immobilized nickel ions using fluorescence and electro-switchable DNA chips. The switchSENSE method was first set up on synthetic peptides known for their metal-chelating properties. Then, it was applied to soy and tilapia viscera protein hydrolysates. Their Cu2+-chelation capacity was, in addition, determined by UV-visible spectrophotometry as a reference method. The switchSENSE method has displayed a high sensitivity to evidence the presence of MCPs in both hydrolysates. Hence, we demonstrate for the first time that this newly introduced technology is a convenient methodology to screen protein hydrolysates in order to determine the presence of MCPs before launching time-consuming separations.


Assuntos
Quelantes , Hidrolisados de Proteína , Antioxidantes , Peptídeos , Tecnologia
9.
Nanoscale ; 13(23): 10566-10578, 2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34100504

RESUMO

Peptide-based hydrogels are physical gels formed through specific supramolecular self-assembling processes, leading to ordered nanostructures which constitute the water entrapping scaffold of the soft material. Thanks to the inherent properties of peptides, these hydrogels are highly considered in the biomedical domain and open new horizons in terms of application in advanced therapies and biotechnologies. The use of one, and only one, native peptide to formulate a gel is by far the most reported approach to design such materials, but suffers from several limitations, including in terms of mechanical properties. To improve peptide-based hydrogels interest and give rise to innovative properties, several strategies have been proposed in the recent years, and the development of multicomponent peptide-based hydrogels appears as a promising and relevant strategy. Indeed, mixing two or more compounds to develop new materials is a much-used approach that has proven its effectiveness in a wide variety of domains, including polymers, composites and alloys. While still limited to a handful of examples, we would like to report herein on the formulation and the comprehensive study of multicomponent hybrid DNA-nucleobase/peptide-based hydrogels using a multiscale approach based on a large panel of analytical techniques (i.e., rheometry, proton relaxometry, SAXS, electronic microscopy, infrared, circular dichroism, fluorescence, Thioflavin T assays). Among the six multicomponent systems studied, the results highlight the synergistic role of the presence of the two complementary DNA-nucleobases (i.e., adenine/thymine and guanine/cytosine) on the co-assembling process from structural (e.g., morphology of the nanoobjects) to physicochemical (e.g., kinetics of formation, fluorescence properties) and mechanical (e.g., stiffness, resistance to external stress) properties. All the data confirm the relevance of the multicomponent peptide-based approach in the design of innovative hydrogels and bring another brick in the wall of the understanding of these complex and promising systems.


Assuntos
Hidrogéis , Nanoestruturas , Peptídeos , Espalhamento a Baixo Ângulo , Difração de Raios X
10.
Anal Bioanal Chem ; 413(2): 315-329, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33386417

RESUMO

Production of iron-chelating peptides from protein hydrolysates requires robust and adequate screening methods to optimize their purification and subsequently valorize their potential antioxidant properties. An original methodology was developed for direct and sensitive screening of iron(II)-chelating peptides based on ion-pair reverse phase liquid chromatography (IP-RPLC) coupled to high-resolution mass spectrometry (HRMS). Peptide mixture was first added to iron(II) solution to form iron(II)-peptide complexes. Then IP-RPLC-HRMS analysis was conducted on this iron-peptide mixture and on the iron-free peptide solution for comparative mass spectra analysis. This protocol, initially applied to a range of low molecular weight standard peptides, allowed detection of [(Peptide-H)+56FeII]+ complex ion for iron(II)-chelating peptides (GGH, EAH, DAH, ßAH, DMH, DTH, DSH). GGH was added in complex peptide mixtures and targeted analysis of [(GGH-H)+56FeII]+ complex showed a limit of detection (LOD) below 0.77 mg L-1 of GGH. This protocol was finally tested in combination with metabolomics software and additional digital processing for non-targeted search for iron(II)-chelating peptides. Applicability of this new screening methodology has been validated by detection of GGH as iron(II)-chelating peptide when added at 0.77 mg L-1 in casein hydrolysate. Graphical abstract.


Assuntos
Quelantes/química , Cromatografia Líquida/métodos , Ferro/química , Metabolômica/métodos , Peptídeos/química , Hidrolisados de Proteína/química , Proteínas/química , Caseínas/química , Processamento Eletrônico de Dados , Hidrólise , Ligantes , Limite de Detecção , Espectrometria de Massas , Espectrometria de Massas por Ionização por Electrospray
11.
Nanoscale ; 12(38): 19905-19917, 2020 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-32985645

RESUMO

Peptide self-assemblies have attracted intense research interest over the last few decades thanks to their implications in key biological processes (e.g., amyloid formation) and their use in biotechnological and (bio)material fields. In particular, peptide-based hydrogels have been highly considered as high potential supramolecular materials in the biomedical domain and open new horizons in terms of applications. To further understand their self-assembly mechanisms and to optimize their properties, several strategies have been proposed with the modification of the constituting amino acid chains via, per se, the introduction of d-amino acids, halogenated amino acids, pseudopeptide bonds, or other chemical moieties. In this context, we report herein on the incorporation of DNA-nucleobases into their peptide nucleic acid (PNA) forms to develop a new series of hybrid nucleopeptides. Thus, depending on the nature of the nucleobase (i.e., thymine, cytosine, adenine or guanine), the physicochemical and mechanical properties of the resulting hydrogels can be significantly improved and fine-tuned with, for instance, drastic enhancements of both the gel stiffness (up to 70-fold) and the gel resistance to external stress (up to 40-fold), and the generation of both thermo-reversible and uncommon red-edge excitation shift (REES) properties. To decipher the actual role of each PNA moiety in the self-assembly processes, the induced modifications from the molecular to the macroscopic scales are studied thanks to the multiscale approach based on a large panel of analytical techniques (i.e., rheology, NMR relaxometry, TEM, thioflavin T assays, FTIR, CD, fluorescence, NMR chemical shift index). Thus, such a strategy provides new opportunities to adapt and fit hydrogel properties to the intended ones and pushes back the limits of supramolecular materials.


Assuntos
Ácidos Nucleicos Peptídicos , Aminoácidos , Proteínas Amiloidogênicas , Hidrogéis , Peptídeos
12.
Metallomics ; 12(8): 1220-1229, 2020 08 19.
Artigo em Inglês | MEDLINE | ID: mdl-32490462

RESUMO

Reactive oxygen species (ROS) are major sources of oxidative stress playing prominent roles in the development of several pathologies including cardiovascular and neurodegenerative diseases or cancers. The presence of transition biometal ions, specifically copper and iron, induces ROS formation by catalyzing the reduction of molecular oxygen to superoxide anion (O2˙-), hydrogen peroxide (H2O2) and hydroxyl (HO˙) radical. To limit ROS production and their detrimental effects, we report on the synthesis, physicochemical studies and antioxidant assays of an innovative series of synthetic pentapeptides exhibiting a dual direct/indirect mode of action, both as iron(iii)-chelators and as radical scavengers. These combined effects lead to a drastic reduction of in vitro reactive oxygen species production up to 95% for the more reactive hydroxyl radical.


Assuntos
Compostos Férricos/química , Radicais Livres/química , Peróxido de Hidrogênio/química , Espécies Reativas de Oxigênio/química , Ferro/química , Estresse Oxidativo , Superóxidos/química
13.
RSC Adv ; 10(71): 43859-43869, 2020 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-35519698

RESUMO

Molecular self-assembly is a fascinating process which has become an area of great interest in supramolecular chemistry, as it leads in certain cases to molecular gels. Organogels formulated from low molecular weight compounds (LMWOGs) have attracted much interest in the past decades due to their applications as new soft materials. Herein, we report on the ability of the cyclic pseudopeptide cyclo-[-(d-Phe-azaPhe-Ala)2-] (2) to self-assemble in some aromatic solvents and to form organogels driven by non-covalent forces, mainly hydrogen bonding and π-stacking interactions. Comprehensive FTIR and NMR studies emphasized that this cyclic aza-peptide adopts a ß-turn conformation at low concentration in toluene, while an equilibrium between the monomeric states (intramolecular forces) and the supramolecular structures (intra- and intermolecular forces) is established at high concentration (gel state). Rheological investigations of the organogels highlight the dependence of their stiffness (up to ∼4 kPa) and sol/gel transition temperatures (up to 100 °C) as a function of the solvent and concentration of gelator used. The formulation of fibrous structures confirmed the phenomenon of self-assembly. Finally, we found that cyclo-[-(d-Phe-azaPhe-Ala)2-] is an effective organogelator for application in phase selective gelation (PSG) of organic solvents from aqueous/organic mixtures with recovery percents up to 96%.

14.
Chimia (Aarau) ; 69(9): 530-6, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26507760

RESUMO

Recent years have witnessed a tremendous increase in the biotechnological applications of nucleic acid-based nanotools. Beyond their biological relevance, nucleobases have indeed found new scopes of applications in bionanotechnology, which are expanding nowadays at an accelerated pace. Among the four canonical nucleobases (adenine, guanine, cytosine and thymine), guanine is certainly the most useful and used base, thanks to its versatile H-bond donating/accepting properties that make it suitable for being involved in various assemblies ranging from base-pairs to base-quartets. Here, we would like to report on an innovative guanine-based molecular tool named Tb. Pyro-DOTASQ: this metal complex has a sophisticated chemical structure that allows formation of an intramolecular G-quartet upon interaction with alternative secondary structures known as G-quadruplexes. This target-promoted molecular switch triggers a luminescence response that would permit the use of Tb. Pyro-DOTASQ to search and detect quadruplex-forming DNA and RNA sequences: its unique design indeed allows it i) to create specific interaction with quadruplexes, ii) to provide an easily readable luminescent output to monitor this association and iii) to be readily immobilized on graphene surface, thus making Tb. Pyro-DOTASQ a high-value molecular device. Results obtained in the course of in-depth biophysical analyses raise questions about the actual supramolecular structure of Tb. Pyro-DOTASQ: these results thus shed a bright light on the care that must be exercised when using intricate molecular architectures to construct elaborated supramolecular metal complexes.


Assuntos
Quadruplex G , Guanina/química , Substâncias Luminescentes/química , Substâncias Luminescentes/síntese química , Medições Luminescentes , Nanotecnologia/métodos , Desenho de Fármacos , Grafite/química , Modelos Moleculares , Compostos Organometálicos/síntese química , Compostos Organometálicos/química , Térbio/química
15.
Nat Commun ; 6: 7574, 2015 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-26123690

RESUMO

Amyloid supramolecular assemblies have found widespread exploitation as ordered nanomaterials in a range of applications from materials science to biotechnology. New strategies are, however, required for understanding and promoting mature fibril formation from simple monomer motifs through easy and scalable processes. Noncovalent interactions are key to forming and holding the amyloid structure together. On the other hand, the halogen bond has never been used purposefully to achieve control over amyloid self-assembly. Here we show that single atom replacement of hydrogen with iodine, a halogen-bond donor, in the human calcitonin-derived amyloidogenic fragment DFNKF results in a super-gelator peptide, which forms a strong and shape-persistent hydrogel at 30-fold lower concentration than the wild-type pentapeptide. This is remarkable for such a modest perturbation in structure. Iodination of aromatic amino acids may thus develop as a general strategy for the design of new hydrogels from unprotected peptides and without using organic solvents.


Assuntos
Amiloide/química , Dicroísmo Circular , Tomografia com Microscopia Eletrônica , Halogenação , Temperatura Alta , Microscopia de Força Atômica , Microscopia Eletrônica de Transmissão , Fenilalanina/análogos & derivados , Conformação Proteica , Estabilidade Proteica , Reologia
16.
J Am Chem Soc ; 136(35): 12406-14, 2014 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-25101894

RESUMO

Recent and unambiguous evidences of the formation of DNA and RNA G-quadruplexes in cells has provided solid support for these structures to be considered as valuable targets in oncology. Beyond this, they have lent further credence to the anticancer strategies relying on small molecules that selectively target these higher-order DNA/RNA architectures, referred to as G-quadruplex ligands. They have also shed bright light on the necessity of designing multitasking ligands, displaying not only enticing quadruplex interacting properties (affinity, structural selectivity) but also additional features that make them usable for detecting quadruplexes in living cells, notably for determining whether, when, and where these structures fold and unfold during the cell cycle and also for better assessing the consequences of their stabilization by external agents. Herein, we report a brand new design of such multitasking ligands, whose structure experiences a quadruplex-promoted conformational switch that triggers not only its quadruplex affinity (i.e., smart ligands, which display high affinity and selectivity for DNA/RNA quadruplexes) but also its fluorescence (i.e., smart probes, which behave as selective light-up fluorescent reporters on the basis of a fluorogenic electron redistribution). The first prototype of such multifunctional ligands, termed PyroTASQ, represents a brand new generation of quadruplex ligands that can be referred to as "twice-as-smart" quadruplex ligands.


Assuntos
Corantes Fluorescentes/química , Quadruplex G , Sequência de Bases , DNA/química , Transferência Ressonante de Energia de Fluorescência , Ligantes , Modelos Moleculares , RNA/química
17.
ChemMedChem ; 9(9): 2035-9, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24678052

RESUMO

Secondary nucleic acid structures, such as DNA and RNA quadruplexes, are potential targets for cancer therapies. Ligands that interact with these targets could thus find application as anticancer agents. Synthetic G-quartets have recently found numerous applications, including use as bioinspired G-quadruplex ligands. Herein, the design, synthesis and preliminary biophysical evaluation of a new prototype multitarget G-quadruplex ligand, (PNA)PorphySQ, are reported, where peptidic nucleic acid guanine ((PNA)G) was incorporated in the porphyrin-templated synthetic G-quartet (PorphySQ). Using fluorescence resonance energy transfer (FRET)-melting experiments, PorphySQ was shown to possess enhanced quadruplex-interacting properties thanks to the presence of four positively charged (PNA)G residues that improve its electrostatic interactions with the binding site of both DNA and RNA quadruplexes (i.e., their negatively charged and accessible G-quartets), thereby making (PNA)PorphySQ an interesting prototype of a multitarget ligand. Both the chemical stability and water solubility of (PNA)PorphySQ are improved over the non-PNA derivative (PorphySQ), which are desirable properties for drug development, and while improvements remain to be made, this ligand is a promising lead for the further development of multitarget G-quadruplex ligands.


Assuntos
Quadruplex G/efeitos dos fármacos , Porfirinas/química , Sítios de Ligação , DNA/efeitos dos fármacos , Guanina/química , Ligantes , Modelos Moleculares , Conformação de Ácido Nucleico , Ácidos Nucleicos Peptídicos/química , RNA/efeitos dos fármacos , Relação Estrutura-Atividade
18.
Inorg Chem ; 53(4): 2296-303, 2014 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-24499428

RESUMO

A new series of gold(I) N-heterocyclic carbene (NHC) complexes based on xanthine ligands have been synthesized and characterized by mass spectrometry, NMR, and X-ray diffraction. The compounds have been tested for their antiproliferative properties in human cancer cells and nontumorigenic cells in vitro, as well as for their toxicity in healthy tissues ex vivo. The bis-carbene complex [Au(caffein-2-ylidene)2][BF4] (complex 4) appeared to be selective for human ovarian cancer cell lines and poorly toxic in healthy organs. To gain preliminary insights into their actual mechanism of action, two biologically relevant in cellulo targets were studied, namely, DNA (more precisely a higher-order DNA structure termed G-quadruplex DNA that plays key roles in oncogenetic regulation) and a pivotal enzyme of the DNA damage response (DDR) machinery (poly-(adenosine diphosphate (ADP)-ribose) polymerase 1 (PARP-1), strongly involved in the cancer resistance mechanism). Our results indicate that complex 4 acts as an efficient and selective G-quadruplex ligand while being a modest PARP-1 inhibitor (i.e., poor DDR impairing agent) and thus provide preliminary insights into the molecular mechanism that underlies its antiproliferative behavior.


Assuntos
Antineoplásicos/química , Antineoplásicos/farmacologia , Cafeína/química , Ouro/química , Metano/análogos & derivados , Animais , Antineoplásicos/síntese química , Linhagem Celular , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Compostos Heterocíclicos/síntese química , Compostos Heterocíclicos/química , Compostos Heterocíclicos/farmacologia , Humanos , Concentração Inibidora 50 , Ligantes , Metano/química , Estrutura Molecular , Xantina/química
19.
Nanoscale ; 6(5): 2693-701, 2014 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-24452273

RESUMO

The structure of the double helix of deoxyribonucleic acid (DNA, also called duplex-DNA) was elucidated sixty years ago by Watson, Crick, Wilkins and Franklin. Since then, DNA has continued to hold a fascination for researchers in diverse fields including medicine and nanobiotechnology. Nature has indeed excelled in diversifying the use of DNA: beyond its canonical role of repository of genetic information, DNA could also act as a nanofactory able to perform some complex catalytic tasks in an enzyme-mimicking manner. The catalytic capability of DNA was termed DNAzyme; in this context, a peculiar DNA structure, a quadruple helix also named quadruplex-DNA, has recently garnered considerable interest since its autonomous catalytic proficiency relies on its higher-order folding that makes it suitable to interact efficiently with hemin, a natural cofactor of many enzymes. Quadruplexes have thus been widely studied for their hemoprotein-like properties, chiefly peroxidase-like activity, i.e., their ability to perform hemin-mediated catalytic oxidation reactions. Recent literature is replete with applications of quadruplex-based peroxidase-mimicking DNAzyme systems. Herein, we take a further leap along the road to biochemical applications, assessing the actual efficiency of catalytic quadruplexes for the detection of picomolar levels of surface-bound analytes in an enzyme-linked immunosorbent (ELISA)-type assay. To this end, we exploit an innovative strategy based on the functionalization of DNA by a multitasking platform named RAFT (for regioselectivity addressable functionalized template), whose versatility enables the grafting of DNA whatever its nature (duplex-DNA, quadruplex-DNA, etc.). We demonstrate that the resulting biotinylated RAFT/quadruplex systems indeed acquire catalytic properties that allow for efficient luminescent detection of picomoles of surface-bound streptavidin. We also highlight some of the pitfalls that have to be faced during optimization, notably demonstrating that highly optimized experimental conditions can make DNA pre-catalysts catalytically competent whatever their secondary structures.


Assuntos
DNA Catalítico/metabolismo , Biocatálise , DNA Catalítico/química , Quadruplex G , Ácidos Nucleicos Imobilizados/química , Ácidos Nucleicos Imobilizados/metabolismo , Oxirredução , Peroxidases/química , Peroxidases/metabolismo , Propriedades de Superfície
20.
Chemistry ; 19(38): 12739-47, 2013 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-23922305

RESUMO

Natural G-quartets, a cyclic and coplanar array of four guanine residues held together through a Watson-Crick/Hoogsteen hydrogen-bond network, have received recently much attention due to their involvement in G-quadruplex DNA, an alternative higher-order DNA structure strongly suspected to play important roles in key cellular events. Besides this, synthetic G-quartets (SQ), which artificially mimic native G-quartets, have also been widely studied for their involvement in nanotechnological applications (i.e., nanowires, artificial ion channels, etc.). In contrast, intramolecular synthetic G-quartets (iSQ), also named template-assembled synthetic G-quartets (TASQ), have been more sparingly investigated, despite a technological potential just as interesting. Herein, we report on a particular iSQ named (PNA) DOTASQ, which demonstrates very interesting properties in terms of DNA and RNA interaction (notably its selective recognition of quadruplexes according to a bioinspired process) and catalytic activities, through its ability to perform peroxidase-like hemin-mediated oxidations either in an autonomous fashion (i.e., as pre-catalyst for TASQzyme reactions) or in conjunction with quadruplex DNA (i.e., as enhancing agents for DNAzyme processes). These results provide a solid scientific basis for TASQ to be used as multitasking tools for bionanotechnological applications.


Assuntos
Quadruplex G , RNA/química , Biocatálise , DNA/química , Hemina/química , Hemina/metabolismo , Oxirredução , Água/química
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...