RESUMO
Zinc-dependent histone deacetylases (HDACs) are important epigenetic regulators that have become important drug targets for treating cancer. Although five HDAC inhibitors have been approved for treating several cancers, there is still a huge demand on discovering new HDAC inhibitors to explore the therapeutic potentials for treating solid tumor cancers. Substrate mimics are a powerful rational design approach for the development of potent inhibitors. Here we describe the rational design, synthesis, biological evaluation, molecular docking and in vivo efficacy study of a class of HDAC inhibitors using Nε-acetyl lysine mimics that are derived from cysteine. As a result, compounds 7a, 9b and 13d demonstrated pan-HDAC inhibition and broad cytotoxicity against several cancer cell lines, comparable to the approved HDAC inhibitor SAHA. Furthermore, 13d significantly inhibited tumor growth in a A549 xenograft mice model without any obvious weight loss, supporting that the cysteine-derived acetyl lysine mimics are promising HDAC inhibitors with therapeutic potentials for treating cancer.
Assuntos
Antineoplásicos/farmacologia , Cisteína/farmacologia , Inibidores de Histona Desacetilases/farmacologia , Histona Desacetilases/metabolismo , Lisina/farmacologia , Zinco/metabolismo , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Cisteína/síntese química , Cisteína/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Inibidores de Histona Desacetilases/síntese química , Inibidores de Histona Desacetilases/química , Humanos , Lisina/química , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Simulação de Acoplamento Molecular , Estrutura Molecular , Neoplasias Experimentais/tratamento farmacológico , Neoplasias Experimentais/metabolismo , Neoplasias Experimentais/patologia , Relação Estrutura-AtividadeRESUMO
Herein, we developed a bifunctional reagent rac-2-Br-DMNPA 2 for the late-stage protection of peptide cysteine. Through the identification of its t-Bu ester 1 as a more competent form under ligation conditions, facile N-terminal and side-chain caging for the model peptide and protein were accomplished. Building upon this, a one-pot ligation and photolysis strategy was applied in the synthesis of the mini-protein chlorotoxin. More importantly, we extended the utility of 2 as a bifunctional linker for traceless solid-phase chemical ligation.
Assuntos
Butiratos/química , Cisteína/síntese química , Peptídeos/síntese química , Cisteína/química , Ésteres , Estrutura Molecular , Peptídeos/químicaRESUMO
5-(Alkynyl)dibenzothiophenium triflates are introduced as new reagents to prepare different protein conjugates through site-selective cysteine alkynylation. The protocol developed allows a highly efficient label of free cysteine-containing proteins with relevant biological roles, such as ubiquitin, the C2A domain of Synaptotagmin-I, or HER2 targeting nanobodies. An electrophilic bis-alkynylating reagent was also designed. The second alkynylating handle thus introduced in the desired protein enables access to protein-thiol, protein-peptide, and protein-protein conjugates, and even diubiquitin dimers can be prepared through this approach. The low excess of reagent needed, mild reaction conditions used, short reaction times, and stability of the S-C(alkyne) bonds at physiological conditions make this approach an interesting addition to the toolbox of classical, site-selective cysteine-conjugation methods.
Assuntos
Alcinos/química , Proteínas/química , Tiofenos/química , Alcinos/síntese química , Animais , Técnicas de Química Sintética , Cisteína/síntese química , Cisteína/química , Humanos , Indicadores e Reagentes , Mesilatos/síntese química , Mesilatos/química , Modelos Moleculares , Proteínas/síntese química , Compostos de Sulfidrila/química , Tiofenos/síntese químicaRESUMO
Antibody-drug conjugates (ADCs) have attracted great attention in recent years in the wake of an accelerated FDA approval rate and several large-scale acquisitions. To date, there are ten ADC drugs on the market and more than 70 in various stages of clinical trials. Yet, due to the complicated nature of ADC molecules, considerations need to cover many aspects for the success of ADCs, including target specificity, linker-payload stability, tumor permeability, and clearance rate. This topical review summarizes and discusses current methods used to increase stability and homogeneity of ADCs of cysteine conjugation. We believe that they will lead to improvement of efficacy and pharmacokinetics (PK) of ADC drugs.
Assuntos
Cisteína/química , Imunoconjugados/química , Animais , Antineoplásicos Imunológicos/síntese química , Antineoplásicos Imunológicos/química , Antineoplásicos Imunológicos/farmacocinética , Técnicas de Química Sintética/métodos , Cisteína/síntese química , Cisteína/farmacocinética , Humanos , Imunoconjugados/farmacocinética , Neoplasias/tratamento farmacológicoRESUMO
Posttranslational modification (PTM), through the recruitment of effector proteins (i.e., "readers") that signal downstream events, plays key roles in regulating a variety of cellular processes. To understand how a PTM is recognized, it is necessary to find its readers and, importantly, the location of the binding pockets responsible for PTM recognition. Although various methods have been developed to identify PTM readers, it remains a challenge to directly map the PTM-binding regions, especially for intrinsically disordered domains. Here, we demonstrate a photo-crosslinkable, clickable, and cleavable tri-functional amino acid, ADdis-Cys, that when coupled with mass spectrometry (ADdis-Cys-MS) can not only identify PTM readers from complex proteomes but also simultaneously map their PTM-recognition modules. Using ADdis-Cys-MS, we successfully identify the binding sites of several reader-PTM interactions, among which we discover human C1QBP as a histone chaperone. This robust method should find wide applications in examining other histone or non-histone PTM-mediated protein-protein interactions.
Assuntos
Aminoácidos/química , Aminoácidos/metabolismo , Mapeamento de Interação de Proteínas/métodos , Aminoácidos/genética , Sítios de Ligação , Química Click/métodos , Reagentes de Ligações Cruzadas , Cisteína/análogos & derivados , Cisteína/síntese química , Cisteína/química , Histonas/metabolismo , Humanos , Espectrometria de Massas/métodos , Mapas de Interação de Proteínas/genética , Mapas de Interação de Proteínas/fisiologia , Processamento de Proteína Pós-Traducional/genética , Processamento de Proteína Pós-Traducional/fisiologia , Proteoma/metabolismo , Proteômica/métodosRESUMO
Kinesin spindle protein (KSP) is expressed only in cells undergoing cell division, and hence represents an attractive target for the treatment of cancer. Several KSP inhibitors have been developed and undergone clinical trial, but their clinical use is limited by their toxicity to rapidly proliferating non-cancerous cells. To create new KSP inhibitors that are highly selective for cancer cells, we optimized the amino acid moiety of S-trityl-l-cysteine (STLC) derivative 1 using in silico modeling. Molecular docking and molecular dynamics simulation were performed to investigate the binding mode of 1 with KSP. Consistent with the structure activity relationship studies, we found that a cysteine amino moiety plays an important role in stabilizing the interaction. Based on these findings and the structure of GSH, a substrate of γ-glutamyltransferase (GGT), we designed and synthesized the prodrug N-γ-glutamylated STLC derivative 9, which could be hydrolyzed by GGT to produce 1. The KSP ATPase inhibitory activity of 9 was lower than that of 1, and LC-MS analysis indicated that 9 was converted to 1 only in the presence of GGT in vitro. In addition, the cytotoxic activity of 9 was significantly attenuated in GGT-knockdown A549 cells. Since GGT is overexpressed on the cell membrane of various cancer cells, these results suggest that compound 9 could be a promising prodrug that selectively inhibits the proliferation of GGT-expressing cancer cells.
Assuntos
Antineoplásicos/farmacologia , Cisteína/farmacologia , Dibenzocicloeptenos/farmacologia , Cinesinas/antagonistas & inibidores , Pró-Fármacos/farmacologia , Compostos de Tritil/farmacologia , Animais , Antineoplásicos/síntese química , Antineoplásicos/metabolismo , Bovinos , Linhagem Celular Tumoral , Cisteína/síntese química , Cisteína/metabolismo , Dibenzocicloeptenos/síntese química , Dibenzocicloeptenos/metabolismo , Humanos , Cinesinas/metabolismo , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Estrutura Molecular , Pró-Fármacos/síntese química , Pró-Fármacos/metabolismo , Ligação Proteica , Relação Estrutura-Atividade , Termodinâmica , Compostos de Tritil/síntese química , Compostos de Tritil/metabolismo , gama-Glutamiltransferase/metabolismoRESUMO
Based on the structure of the natural product cysteine, a series of thiazolidine-4-carboxylic acids were designed and synthesized. All target compounds bearing thiazolidine-4-carboxylic acid were characterized by 1H-NMR, 13C-NMR, and HRMS techniques. The antiviral and antifungal activities of cysteine and its derivatives were evaluated in vitro and in vivo. The results of anti-TMV activity revealed that all compounds exhibited moderate to excellent activities against tobacco mosaic virus (TMV) at the concentration of 500 µg/mL. The compounds cysteine (1), 3-4, 7, 10, 13, 20, 23, and 24 displayed higher anti-TMV activities than the commercial plant virucide ribavirin (inhibitory rate: 40, 40, and 38% at 500 µg/mL for inactivation, curative, and protection activity in vivo, respectively), especially compound 3 (inhibitory rate: 51%, 47%, and 49% at 500 µg/mL for inactivation, curative, and protection activity in vivo, respectively) with excellent antiviral activity emerged as a new antiviral candidate. Antiviral mechanism research by TEM exhibited that compound 3 could inhibit virus assembly by aggregated the 20S protein disk. Molecular docking results revealed that compound 3 with higher antiviral activities than that of compound 24 did show stronger interaction with TMV CP. Further fungicidal activity tests against 14 kinds of phytopathogenic fungi revealed that these cysteine derivatives displayed broad-spectrum fungicidal activities. Compound 16 exhibited higher antifungal activities against Cercospora arachidicola Hori and Alternaria solani than commercial fungicides carbendazim and chlorothalonil, which emerged as a new candidate for fungicidal research.
Assuntos
Alternaria/efeitos dos fármacos , Antifúngicos/farmacologia , Antivirais/farmacologia , Ascomicetos/efeitos dos fármacos , Cisteína/farmacologia , Vírus do Mosaico do Tabaco/efeitos dos fármacos , Antifúngicos/síntese química , Antifúngicos/química , Antivirais/síntese química , Antivirais/química , Cisteína/síntese química , Cisteína/química , Descoberta de Drogas , Testes de Sensibilidade Microbiana , Estrutura MolecularRESUMO
Peptide biosynthesis is performed by ribosomes and several other classes of enzymes, but a simple chemical synthesis may have created the first peptides at the origins of life. α-Aminonitriles-prebiotic α-amino acid precursors-are generally produced by Strecker reactions. However, cysteine's aminothiol is incompatible with nitriles. Consequently, cysteine nitrile is not stable, and cysteine has been proposed to be a product of evolution, not prebiotic chemistry. We now report a high-yielding, prebiotic synthesis of cysteine peptides. Our biomimetic pathway converts serine to cysteine by nitrile-activated dehydroalanine synthesis. We also demonstrate that N-acylcysteines catalyze peptide ligation, directly coupling kinetically stable-but energy-rich-α-amidonitriles to proteinogenic amines. This rare example of selective and efficient organocatalysis in water implicates cysteine as both catalyst and precursor in prebiotic peptide synthesis.
Assuntos
Cisteína/síntese química , Nitrilas/química , Origem da Vida , Peptídeos/síntese química , Alanina/análogos & derivados , Alanina/síntese química , Catálise , Cisteína/química , Cinética , Peptídeos/química , Serina/químicaRESUMO
Site-specific glycosylation of a functional recombinant protein thioester is reported. The thioester functionalized protein sfGFP-Y151ThioD, prepared by genetic code expansion, underwent native chemical ligation with the cysteine-conjugated glycans H-Cys-NH-GlcNAc and H-Cys-NH-(GlcNAc)2(Man)3 to give the corresponding cysteine-bridged glycoproteins. The intact glycoproteins, which retained their fluorescence, were characterized by top-down mass spectrometry and gel electrophoresis. The bridging cysteine provided a convenient handle for affinity chromatography purification of the glycoproteins via a removable biotin tag. Given the influence that specific glycoforms can have on a protein's function, the ability to attach a homogeneous glycan to an intact protein in a functional group controlled yet sequon-independent manner could find widespread application. These preliminary results set the stage for development of the expressed protein glycoligation (EPG) concept.
Assuntos
Cisteína/química , Glicoproteínas/síntese química , Biocatálise , Cisteína/síntese química , Escherichia coli/genética , Glicoproteínas/química , Glicoproteínas/genética , Modelos Moleculares , Técnicas de Síntese em Fase SólidaRESUMO
Human serum albumin is widely used in clinical practice, and the development of new ligands with high affinity is beneficial to improve its separation efficiency. The Site II of human serum albumin is an active binding site of various molecules such as l-tryptophan, which was studied with molecular simulation to obtain insights for the design of new ligands. The results showed that the carboxyl and indolyl groups of l-tryptophan were critical for the binding on Site II. Seven ligands containing carboxyl groups and indolyl groups were designed, and molecular simulation showed that indole-3-pentanoic acid was the best ligand. A new ligand combined indole-3-acetic acid and cysteine was designed for easier resin preparation, and molecular simulation also indicated that the new ligand bound strongly to Site II. Resins with the new ligand designed was prepared and static adsorption experiments indicated that the new resin had high adsorption capacity of human serum albumin and strong salt tolerance. Finally, recombinant human serum albumin was separated from yeast broth with high purity of 90.4% and recovery of 94.2%, which indicated that the new resin had good adsorption selectivity and strong potential for applications.
Assuntos
Cisteína/química , Desenho de Fármacos , Ácidos Indolacéticos/química , Albumina Sérica Humana/isolamento & purificação , Triptofano/química , Sítios de Ligação , Cisteína/síntese química , Humanos , Ácidos Indolacéticos/síntese química , Ligantes , Simulação de Dinâmica Molecular , Estrutura Molecular , Albumina Sérica Humana/química , Triptofano/síntese químicaRESUMO
Antibiotic resistance amongst microbial pathogens is a mounting serious issue in researchers and physicians. Various alternatives to overcome the multidrug-resistant bacterial infections are under search, and biofilm growth inhibition is one of them. In this investigation, a polymeric drug delivery system loaded with multi-serratial drugs to improve the delivery of drugs against urinary tract infection causative Serratia marcescens. The chitosan grafted pyromellitic dianhydride - cysteine (CS-g-PMDA-CYS) was conjugated with AuNPs by using the -SH group of CYS and RF (rifampicin) and INH (isoniazid) were loaded in AuNPs-fused CS-g-PMDA-CYS system. Several physicochemical techniques characterized this fabricated AuNPs/RF/INH/CS-g-PMDA-CYS system. The successful encapsulation of RF and INH in AuNPs-fused CS-g-PMDA-CYS polymer had confirmed, and it observed the loading capacity for RF and INH was 9.02% and 13.12%, respectively. The in vitro drug discharge pattern was perceived high in pH 5.5 compared with pH 7.4. The AuNPs/RF/INH/CS-g-PMDA-CYS escalates 74% of Caenorhabditis elegans survival during Serratia marcescens infection by aiming biofilm development and virulence in S. marcescens. Author postulate that the fabricated system is a promising drug carrier and delivery system for inhibition of multidrug-resistant bacterias like S. marcescens.
Assuntos
Antibacterianos/administração & dosagem , Sistemas de Liberação de Medicamentos/métodos , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Compostos de Ouro/administração & dosagem , Nanopartículas Metálicas/administração & dosagem , Serratia marcescens/efeitos dos fármacos , Animais , Antibacterianos/química , Benzoatos/administração & dosagem , Benzoatos/síntese química , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/microbiologia , Caenorhabditis elegans/fisiologia , Quitosana/administração & dosagem , Quitosana/síntese química , Cisteína/administração & dosagem , Cisteína/síntese química , Farmacorresistência Bacteriana Múltipla/fisiologia , Compostos de Ouro/síntese química , Nanopartículas Metálicas/química , Testes de Sensibilidade Microbiana/métodos , Infecções por Serratia/tratamento farmacológico , Serratia marcescens/fisiologia , Infecções Urinárias/tratamento farmacológico , Difração de Raios X/métodosRESUMO
This article presents data on the synthesis, identification, computer simulation and biocompatibility of graphene oxide (GO) functionalized with L-cysteine (GFC). It was determined that GO reacts with L-cysteine in two different ways: in an alkaline medium, L-cysteine reduces functional groups on the surface and at the boundaries of GO; with heating and the use of thionyl chloride, L-cysteine covalently attaches to GO through carboxylic groups only at the boundaries. The identification of GO, reduced graphene oxide and GFC was performed using various physicochemical methods, including infrared spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis, scanning electron microscopy and high-resolution transmission electron microscopy. Biocompatibility experiments included erythrocyte hemolysis, platelet aggregation, photodynamic and antiradical activity, binding to human serum albumin, and geno- and cytotoxicity studies. Applying density functional theory and molecular dynamics allowed us to obtain the structural and dynamic characteristics of a GFC-water binary system.
Assuntos
Materiais Biocompatíveis/química , Cisteína/química , Eritrócitos/efeitos dos fármacos , Grafite/química , Materiais Biocompatíveis/síntese química , Materiais Biocompatíveis/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cisteína/síntese química , Cisteína/farmacologia , Grafite/síntese química , Grafite/farmacologia , Humanos , Microscopia Eletrônica de Varredura , Análise Espectral Raman , Óxidos de Enxofre/química , Óxidos de Enxofre/farmacologiaRESUMO
To gain more insight into the factors controlling efficient cysteine arylation by cyclometallated AuIII complexes, the reaction between selected gold compounds and different peptides was investigated by high-resolution liquid chromatography electrospray ionization mass spectrometry (HR-LC-ESI-MS). The deduced mechanisms of C-S cross-coupling, also supported by density functional theory (DFT) and quantum mechanics/molecular mechanics (QM/MM) calculations, evidenced the key role of secondary peptidic gold binding sites in favouring the process of reductive elimination.
Assuntos
Cisteína/síntese química , Ouro/química , Compostos Organoáuricos/química , Peptídeos/química , Cisteína/química , Teoria da Densidade Funcional , Modelos Moleculares , Estrutura Molecular , Compostos Organoáuricos/síntese químicaRESUMO
Gaining a fundamental insight into the biomolecular recognition of posttranslationally modified histones by epigenetic reader proteins is of crucial importance to understanding the regulation of the activity of human genes. Here, we seek to establish whether trimethylthialysine, a simple trimethyllysine analogue generated through cysteine alkylation, is a good trimethyllysine mimic for studies on molecular recognition by reader proteins. Histone peptides bearing trimethylthialysine and trimethyllysine were examined for binding with five human reader proteins employing a combination of thermodynamic analyses, molecular dynamics simulations and quantum chemical analyses. Collectively, our experimental and computational findings reveal that trimethylthialysine and trimethyllysine exhibit very similar binding characteristics for the association with human reader proteins, thereby justifying the use of trimethylthialysine for studies aimed at dissecting the origin of biomolecular recognition in epigenetic processes that play important roles in human health and disease.
Assuntos
Cisteína/análogos & derivados , Histonas/química , Lisina/análogos & derivados , Sítios de Ligação , Cisteína/síntese química , Cisteína/química , Epigênese Genética , Histonas/metabolismo , Humanos , Lisina/síntese química , Lisina/química , Metilação , Modelos Moleculares , Conformação Molecular , Ligação Proteica , Técnicas de Síntese em Fase Sólida , Relação Estrutura-Atividade , TermodinâmicaRESUMO
N-Phthalimido-d-cysteine allyl ester was S-alkylated with 2-iodoethanol. The derived ß-thioaldehyde was condensed with Nα-tetrachlorophthalimidovalinamide to afford a Z-thioenamide. Removal of the tetrachlorophthalimido protecting group and homologation with N-Boc-l-leucine afforded the linear tripeptide. Removal of the Boc and allyl protecting groups, followed by carbodiimide-mediated cyclization, led to the 13-membered ring with the aminovinylcysteine moiety embedded. This constitutes the C-terminal macrocycle of all known members of the linardin family of peptides, including the antileukemia agent, cypemycin.
Assuntos
Bacteriocinas/síntese química , Cisteína/análogos & derivados , Peptídeos/química , Bacteriocinas/química , Ciclização , Cisteína/síntese química , Cisteína/química , Estrutura Molecular , Peptídeos/metabolismoRESUMO
Cancer immunotherapy has gained increasing attention due to its potential specificity and lack of adverse side effects when compared to more traditional modes of treatment. Toll-like receptor 2 (TLR2) agonists are lipopeptides possessing the S-[2,3-bis(palmitoyloxy)propyl]-l-cysteine (Pam2Cys) motif and exhibit potent immunostimulatory effects. These agonists offer a means of providing "danger signals" in order to activate the immune system toward tumor antigens. Thus, the development of TLR2 agonists is attractive in the search of potential immunostimulants for cancer. Existing SAR studies of Pam2Cys with TLR2 indicate that the structural requirements for activity are, for the most part, very intolerable. We have investigated the importance of stereochemistry, the effect of N-terminal acylation, and homologation between the two ester functionalities in Pam2Cys-conjugated lipopeptides on TLR2 activity. The R diastereomer is significantly more potent than the S diastereomer and N-terminal modification generally lowers TLR2 activity. Most notably, homologation gives rise to analogues which are comparatively active to the native Pam2Cys containing constructs.
Assuntos
Adjuvantes Imunológicos/química , Adjuvantes Imunológicos/farmacologia , Lipopeptídeos/química , Lipopeptídeos/farmacologia , Receptor 2 Toll-Like/agonistas , Adjuvantes Imunológicos/síntese química , Vacinas Anticâncer/farmacologia , Cisteína/análogos & derivados , Cisteína/síntese química , Cisteína/farmacologia , Humanos , Lipopeptídeos/síntese química , Neoplasias/prevenção & controle , Estereoisomerismo , Receptor 2 Toll-Like/metabolismoRESUMO
The photo-control of protein activity can often be achieved via the photo-control of protein structure. Intramolecular cross-linkers that change length upon photoisomerization provide a means to photo-control protein structure by linking to pairs of Cys residues in a protein sequence. In this protocol, we describe general methods for introducing intramolecular cross-linkers, both UV light switchable and red-light switchable, under either denaturing or native conditions.
Assuntos
Compostos Azo/química , Reagentes de Ligações Cruzadas/química , Cisteína/química , Proteínas/química , Sequência de Aminoácidos , Compostos Azo/síntese química , Técnicas de Química Sintética/métodos , Cromatografia Líquida de Alta Pressão/métodos , Reagentes de Ligações Cruzadas/síntese química , Cisteína/síntese química , Luz , Modelos Moleculares , Processos Fotoquímicos , Conformação Proteica , Dobramento de Proteína , Proteínas/síntese química , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Espectrofotometria Ultravioleta/métodos , Raios UltravioletaRESUMO
Persulfides have been considered as potential signaling compounds similar to the H2S in "S-persulfidation", a sulfur-mediated redox cycle. The research of this sulfur-mediated species is hindered because of the lack of efficient persulfide donors. In this current study, we have developed one- and two-photon-activated persulfide donors based on an o-nitrobenzyl (ONB) phototrigger, which releases the biologically active persulfide (N-acetyl l-cysteine persulfide, NAC-SSH) in a spatiotemporal manner. Next, we have demonstrated the detection of persulfide release both qualitatively and quantitatively using the well-known "turn on" fluorescence probe, that is, monobromobimane, and the trapping agent, that is, 2,4-dinitrofluorobenzene, respectively. Furthermore, we examined the cytotoxicity of synthesized persulfide donors on HeLa cells and the cytoprotective ability in the highly oxidizing cellular environment.
Assuntos
Antineoplásicos/síntese química , Antioxidantes/síntese química , Cisteína/análogos & derivados , Dissulfetos/síntese química , Descoberta de Drogas/métodos , Fótons , Antineoplásicos/química , Antineoplásicos/farmacologia , Antioxidantes/química , Antioxidantes/farmacologia , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cisteína/síntese química , Cisteína/química , Cisteína/farmacologia , Citoproteção/efeitos dos fármacos , Dissulfetos/química , Dissulfetos/farmacologia , Relação Dose-Resposta a Droga , Células HeLa , Humanos , Estrutura Molecular , Terapia de Alvo MolecularRESUMO
This is the first report describing an analytical method for quantitative analysis of two naturally occurring sulphur compounds, S-methyl-l-cysteine (SMC) and S-methyl-l-cysteine sulfoxide (SMCSO), in human body fluids using isotope-labelled internal standards and liquid chromatography-mass spectrometry (LC-MS)/MS techniques. This method was validated according to the guideline of the Royal Society of Chemistry Analytical Methods Committee. It offers significant advantages including simple and fast preparation of human biological samples. The limits of detection of SMC were 0.08 µM for urine and 0.04 µM for plasma. The limits of detection of SMCSO were 0.03 µM for urine and 0.02 µM for plasma. The calibration curves of all matrices showed linearity with correlation coefficients r2 > 0.9987. The intra and inter day precisions in three levels of known concentrations were >10% and >20%, respectively. The quantification accuracy was 98.28 ± 5.66%. The proposed method would be beneficial for the rapid and accurate determination of the SMC and SMCSO in human plasma and urine samples using by isotope labelled internal standards.
Assuntos
Cromatografia Líquida/métodos , Cisteína/análogos & derivados , Espectrometria de Massas em Tandem/métodos , Adolescente , Adulto , Idoso , Cisteína/sangue , Cisteína/síntese química , Cisteína/química , Cisteína/urina , Feminino , Humanos , Marcação por Isótopo , Masculino , Pessoa de Meia-Idade , Padrões de Referência , Reprodutibilidade dos Testes , Adulto JovemRESUMO
Compounds that react irreversibly with cysteines have reemerged as potent and selective tools for altering protein function, serving as chemical probes and even clinically approved drugs. The exquisite sensitivity of human immune cell signaling pathways to oxidative stress indicates the likely, yet still underexploited, general utility of covalent probes for selective chemical immunomodulation. Here, we provide an overview of immunomodulatory cysteines, including identification of electrophilic compounds available to label these residues. We focus our discussion on three protein classes essential for cell signaling, which span the 'druggability' spectrum from amenable to chemical probes (kinases), somewhat druggable (proteases), to inaccessible (phosphatases). Using existing inhibitors as a guide, we identify general strategies to guide the development of covalent probes for selected undruggable classes of proteins and propose the application of such compounds to alter immune cell functions.