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1.
Chemistry ; : e202403508, 2024 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-39448542

RESUMO

Cancer immunotherapy has emerged as one of the most promising modalities for cancer treatment providing hopes of cancer patients with the significant advantages over traditional antitumor therapy methods. Supramolecular assemblies based on host-guest interactions have been widely explored in the field of cancer immunotherapy as the delivery systems. A variety of supramolecular materials show unique features for efficient drug encapsulation, targeting delivery and release, which are favorable to activate antitumor immune responses especially through combination of different treatment strategies. In this review article, we summarize the research progresses of supramolecular assemblies via host-guest interactions for tumor immunotherapy. The construction of various drug delivery systems including hydrogels, liposomes, and polymeric nanoparticles, the drug encapsulation and delivery, as well as advantages and disadvantages are discussed. The perspectives related to future developments in this field are also described.

2.
J Agric Food Chem ; 2024 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-39367836

RESUMO

The unregulated use of pesticides, industrial discharge of heavy metals, waste, and agricultural runoff may contaminate surface water and groundwater, consequently threatening ecosystems and human health. Thus, the sensitive detection and degradation of pesticides are essential for safety. In this context, herein, we have developed benzimidazolium-based fluorescent surfactant assemblies TA-1/SDS and TA-2/SDBS, which exhibit aggregation-induced emission enhancement in an aqueous medium. The aggregates (TA-1/SDS and TA-2/SDBS) displayed a turn-on emission response upon interaction with carbendazim and azamethiphos with limits of detection 7.5 and 7.8 nM, respectively. The FE-SEM and AFM studies revealed that TA-1/SDS and TA-2/SDBS undergo self-assembly with the addition of AZA and CBZ, resulting in the formation of dendritic structures. In addition to the quantification of AZA and CBZ, TA-1/SDS and TA-2/SDBS have also been evaluated to degrade both pesticides and validated using 31P NMR spectroscopy and LC-MS spectrometry.

3.
J Appl Crystallogr ; 57(Pt 5): 1446-1455, 2024 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-39387080

RESUMO

X-ray scattering has become a major tool in the structural characterization of nanoscale materials. Thanks to the widely available experimental and computational atomic models, coordinate-based X-ray scattering simulation has played a crucial role in data interpretation in the past two decades. However, simulation of real-space pair distance distribution functions (PDDFs) from small- and wide-angle X-ray scattering, SAXS/WAXS, has been relatively less exploited. This study presents a comparison of PDDF simulation methods, which are applied to molecular structures that range in size from ß-cyclo-dextrin [1 kDa molecular weight (MW), 66 non-hydrogen atoms] to the satellite tobacco mosaic virus capsid (1.1 MDa MW, 81 960 non-hydrogen atoms). The results demonstrate the power of interpretation of experimental SAXS/WAXS from the real-space view, particularly by providing a more intuitive method for understanding of partial structure contributions. Furthermore, the computational efficiency of PDDF simulation algorithms makes them attractive as approaches for the analysis of large nanoscale materials and biological assemblies. The simulation methods demonstrated in this article have been implemented in stand-alone software, SolX 3.0, which is available to download from https://12idb.xray.aps.anl.gov/solx.html.

4.
Angew Chem Int Ed Engl ; : e202416863, 2024 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-39387346

RESUMO

Stimuli-responsive circularly polarized luminescence (CPL) materials have been attaching wide attention in the field of optical information storage and encryption, while still facing the challenge of the realization of high luminescence dissymmetry factors (glum). This work presents a pair of stimuli-responsive chiral co-assemblies P7R3 and P7S3 by combining polymer PFIQ containing iso-quinoline units with chiral inducers. The obtained chiral co-assemblies can reversibly undergo significant modification in CPL behavior under trifluoroacetic acid (TFA) fumigation and annealing treatment, with the |glum| values exhibiting a reversible shift between 0.2 and 0.3. Moreover, the chiral co-assemblies before TFA fumigating can effectively induce achiral emitters to generate intense full-color CPL signals through CPL energy transfer (CPL-ET), with the corresponding |glum| values larger than 0.2. Moreover, information encryption and decryption as well as a multi-level logic gates application are achieved by leveraging the reversible stimuli-responsive CPL activity of the chiral co-assembly. This work provides a new perspective for the construction of stimuli-responsive chiral luminescent materials with large |glum| values and the activation of CPL behavior in achiral emitters.

5.
Beilstein J Org Chem ; 20: 2567-2576, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39403304

RESUMO

Ion pairs of N-(2,6-dimethylphenyl)-substituted triazatriangulenium (TATA+) cation with various counteranions were synthesized to investigate the interactions for the bulky cation. Single-crystal X-ray analysis of the TATA+ ion pairs revealed solid-state ion-pairing assemblies without stacking at the cationic π-planes. The TATA+ cation showed counteranion-dependent assembly structures, with smaller counteranions located at the top of TATA+ and bulkier counteranions displaced from the TATA+ plane to interact with the surrounding TATA+.

6.
Int J Mol Sci ; 25(19)2024 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-39409175

RESUMO

Colorectal cancer (CRC) is the third most common cancer in the world, with an ongoing rising incidence. Despite secure advancements in CRC treatments, challenges such as side effects and therapy resistance remain to be addressed. Photodynamic therapy (PDT) emerges as a promising modality, clinically used in treating different diseases, including cancer. Among the main challenges with current photosensitizers (PS), hydrophobicity and low selective uptake by the tumor remain prominent. Thus, developing an optimal design for PS to improve their solubility and enhance their selective accumulation in cancer cells is crucial for enhancing the efficacy of PDT. Targeted photoactivation triggers the production of reactive oxygen species (ROS), which promote oxidative stress within cancer cells and ultimately lead to their death. Ruthenium (Ru)-based compounds, known for their selective toxicity towards cancer cells, hold potential as anticancer agents. In this study, we investigated the effect of two distinct arene-Ru assemblies, which lodge porphin PS in their inner cavity, and tested them as PDT agents on the HCT116 and HT-29 human CRC cell lines. The cellular internalization of the porphin-loaded assemblies was confirmed by fluorescence microscopy. Additionally, significant photocytotoxicity was observed in both cell lines after photoactivation of the porphin in the cage systems, inducing apoptosis through caspase activation and cell cycle progression disruptions. These findings suggest that arene-Ru assemblies lodging porphin PS are potent candidates for PDT of CRC.


Assuntos
Neoplasias Colorretais , Fotoquimioterapia , Fármacos Fotossensibilizantes , Porfirinas , Espécies Reativas de Oxigênio , Rutênio , Humanos , Fotoquimioterapia/métodos , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/patologia , Neoplasias Colorretais/metabolismo , Rutênio/química , Rutênio/farmacologia , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/química , Porfirinas/química , Porfirinas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Células HT29 , Apoptose/efeitos dos fármacos , Células HCT116 , Sobrevivência Celular/efeitos dos fármacos , Antineoplásicos/farmacologia , Antineoplásicos/química
7.
Chemphyschem ; : e202400826, 2024 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-39331758

RESUMO

Early forms of life on Earth were most likely not complex. Simple non-living molecules may have formed aggregates, or, underwent spontaneous complex organic reactions resulting in build-up of molecular complexity leading to origin of life. Hence, protocell (hypothetical first live cell) models based on fatty acid self-assemblies have been used in many experiments. Sugars, amino acids and nucleic acids are the backbone of any living creature. Myo-inositol (InOH), is structurally similar to pyranose form of ᴅ-glucose. InOH not only has higher stability than simple sugars, but also not easily degraded under extreme conditions. Therefore, InOH would have persisted in the hostile environment of early Earth. Here, our objective is to study the effect of varying concentrations of InOH, a prebiotic sugar-like biomolecule, on the self-assemblies derived from oleic acid using solvation dynamics as a major experimental tool. We have demonstrated that InOH does indeed perturb the membrane of oleic acid/oleate vesicles, which is characterized by more negative zeta potential and faster solvation dynamics of the solvation probe C153. Overall, our results provide significant insight towards understanding the role of carbohydrate osmolytes in relation protocell models.

8.
Innovation (Abingdon) ; 37(3): 832-850, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39234561

RESUMO

Food systems affect and are affected by the interrelated crises of climate change, biodiversity loss, resource depletion and health, amongst others. Transforming to sustainable approaches is vital, yet entangled with uncertainties, complexity and a great value diversion with stakeholders. Deliberative processes such as citizen assemblies offer a valuable contribution to such a transformation, since the crises and their responses affect everyday life, and therefore inviting individual and collective action. Still, who is included and whose knowledge counts affects outcomes. Theoretically anchored in concepts of environmental justice, our study analyses three nation-wide citizens' assemblies on climate change and food systems from Western Europe. It assesses (a) how citizens' assemblies can incorporate a broad set of viewpoints and design more substantive political answers to current crises, and (b) whether citizens' assemblies include environmental justice aspects to facilitate social change. The paper argues that systematic and methodologically reflected inclusion of various positionalities can inspire decision-making processes in that they incorporate procedural, recognition, and distributional justice to address problems of climate change or modern food systems. It concludes with offering further approaches to include more than scientific knowledge in deliberative processes for a just transformation towards sustainability.

9.
Acta Crystallogr D Struct Biol ; 80(Pt 9): 699-712, 2024 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-39268708

RESUMO

Eukaryotic TIR (Toll/interleukin-1 receptor protein) domains signal via TIR-TIR interactions, either by self-association or by interaction with other TIR domains. In mammals, TIR domains are found in Toll-like receptors (TLRs) and cytoplasmic adaptor proteins involved in pro-inflammatory signaling. Previous work revealed that the MAL TIR domain (MALTIR) nucleates the assembly of MyD88TIR into crystalline arrays in vitro. A microcrystal electron diffraction (MicroED) structure of the MyD88TIR assembly has previously been solved, revealing a two-stranded higher-order assembly of TIR domains. In this work, it is demonstrated that the TIR domain of TLR2, which is reported to signal as a heterodimer with either TLR1 or TLR6, induces the formation of crystalline higher-order assemblies of MyD88TIR in vitro, whereas TLR1TIR and TLR6TIR do not. Using an improved data-collection protocol, the MicroED structure of TLR2TIR-induced MyD88TIR microcrystals was determined at a higher resolution (2.85 Å) and with higher completeness (89%) compared with the previous structure of the MALTIR-induced MyD88TIR assembly. Both assemblies exhibit conformational differences in several areas that are important for signaling (for example the BB loop and CD loop) compared with their monomeric structures. These data suggest that TLR2TIR and MALTIR interact with MyD88 in an analogous manner during signaling, nucleating MyD88TIR assemblies unidirectionally.


Assuntos
Fator 88 de Diferenciação Mieloide , Receptor 2 Toll-Like , Receptor 2 Toll-Like/química , Receptor 2 Toll-Like/metabolismo , Fator 88 de Diferenciação Mieloide/química , Fator 88 de Diferenciação Mieloide/metabolismo , Humanos , Domínios Proteicos , Modelos Moleculares , Receptor 6 Toll-Like/química , Receptor 6 Toll-Like/metabolismo , Receptor 1 Toll-Like/química , Receptor 1 Toll-Like/metabolismo , Cristalografia por Raios X/métodos , Receptores de Interleucina-1/química , Receptores de Interleucina-1/metabolismo , Multimerização Proteica
10.
J Neurosci ; 44(43)2024 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-39256049

RESUMO

Neural circuits supporting innate behaviors, such as feeding, exploration, and social interaction, intermingle in the lateral hypothalamus (LH). Although previous studies have shown that individual LH neurons change their firing relative to the baseline during one or more behaviors, the firing rate dynamics of LH populations within behavioral episodes and the coordination of behavior-related LH populations remain largely unknown. Here, using unsupervised graph-based clustering of LH neurons firing rate dynamics in freely behaving male mice, we identified distinct populations of cells whose activity corresponds to feeding, specific times during feeding bouts, or other innate behaviors-social interaction and novel object exploration. Feeding-related cells fired together with a higher probability during slow and fast gamma oscillations (30-60 and 60-90 Hz) than during nonrhythmic epochs. In contrast, the cofiring of neurons signaling other behaviors than feeding was overall similar between slow gamma and nonrhythmic epochs but increased during fast gamma oscillations. These results reveal a neural organization of ethological hierarchies in the LH and point to behavior-specific motivational systems, the dysfunction of which may contribute to mental disorders.


Assuntos
Comportamento Alimentar , Ritmo Gama , Região Hipotalâmica Lateral , Neurônios , Animais , Masculino , Camundongos , Ritmo Gama/fisiologia , Região Hipotalâmica Lateral/fisiologia , Neurônios/fisiologia , Comportamento Alimentar/fisiologia , Camundongos Endogâmicos C57BL , Potenciais de Ação/fisiologia
11.
Angew Chem Int Ed Engl ; : e202415135, 2024 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-39313476

RESUMO

In this study, a new assembly strategy for lyotropic chromonic liquid crystals (LCLCs) is proposed using iπ-iπ interactions, mainly comprising electrostatic and dispersion forces, between charged π-electronic systems to form stacking structures supported by the hydration of triethylene glycol (TEG) units.  Meso-TEG-aryl-substituted porphyrin AuIII complex, an amphiphilic π-electronic cation, showed diverse states and assembly modes in ion pairs depending on the coexisting counteranions.  The PCCp- ion pair formed a hexagonal columnar (Colh) LC phase based on a charge-by-charge assembly, suggesting the formation of an ordered arrangement of charged p-electronic systems through iπ-iπ interactions, with reduced interactions between the TEG chains.  Furthermore, in the presence of water, LCLC behaviors in the Colh and nematic columnar phases according to the amount of water were observed for the PCCp- ion pair via iπ-iπ interactions.  Magnetic-field-induced orientation of the charge-by-charge columnar structures upon dehydration was observed.  Furthermore, single-stranded charge-by-charge columnar structures, as components of the LCLCs, were observed using transmission electron microscopy (TEM).

12.
Front Netw Physiol ; 4: 1430934, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39238837

RESUMO

Epilepsy is a complex, multifaceted disease that affects patients in several ways in addition to seizures, including psychological, social, and quality of life issues, but epilepsy is also known to interact with sleep. Seizures often occur at the boundary between sleep and wake, patients with epilepsy often experience disrupted sleep, and the rate of inter-ictal epileptiform discharges increases during non-REM sleep. The Network Theory of Epilepsy did not address a role for sleep, but recent emphasis on the interaction between epilepsy and sleep suggests that post-seizure sleep may also be involved in the process by which seizures arise and become more severe with time ("epileptogenesis") by co-opting processes related to the formation of long-term memories. While it is generally acknowledged that recurrent seizures arise from the aberrant function of neural circuits, it is possible that the progression of epilepsy is aided by normal, physiological function of neural circuits during sleep that are driven by pathological signals. Studies recording multiple, single neurons prior to spontaneous seizures have shown that neural assemblies activated prior to the start of seizures were reactivated during post-seizure sleep, similar to the reactivation of behavioral neural assemblies, which is thought to be involved in the formation of long-term memories, a process known as Memory Consolidation. The reactivation of seizure-related neural assemblies during sleep was thus described as being a component of Seizure-Related Consolidation (SRC). These results further suggest that SRC may viewed as a network-related aspect of epilepsy, even in those seizures that have anatomically restricted neuroanatomical origins. As suggested by the Network Theory of Epilepsy as a means of interfering with ictogenesis, therapies that interfered with SRC may provide some anti-epileptogenic therapeutic benefit, even if the interference targeted structures that were not involved originally in the seizure. Here, we show how the Network Theory of Epilepsy can be expanded to include neural plasticity mechanisms associated with learning by providing an overview of Memory Consolidation, the mechanisms thought to underlie MC, their relation to Seizure-Related Consolidation, and suggesting novel, anti-epileptogenic therapies targeting interference with network activation in epilepsy following seizures during post-seizure sleep.

13.
Funct Integr Genomics ; 24(5): 153, 2024 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-39223394

RESUMO

Soybean Glycine max L., paleopolyploid genome, poses challenges to its genetic improvement. However, the development of reference genome assemblies and genome sequencing has completely changed the field of soybean genomics, allowing for more accurate and successful breeding techniques as well as research. During the single-cell revolution, one of the most advanced sequencing tools for examining the transcriptome landscape is single-cell RNA sequencing (scRNA-seq). Comprehensive resources for genetic improvement of soybeans may be found in the SoyBase and other genomics databases. CRISPR-Cas9 genome editing technology provides promising prospects for precise genetic modifications in soybean. This method has enhanced several soybean traits, including as yield, nutritional value, and resistance to both biotic and abiotic stresses. With base editing techniques that allow for precise DNA modifications, the use of CRISPR-Cas9 is further increased. With the availability of the reference genome for soybeans and the following assembly of wild and cultivated soybeans, significant chromosomal rearrangements and gene duplication events have been identified, offering new perspectives on the complex genomic structure of soybeans. Furthermore, major single nucleotide polymorphisms (SNPs) linked to stachyose and sucrose content have been found through genome-wide association studies (GWAS), providing important tools for enhancing soybean carbohydrate profiles. In order to open up new avenues for soybean genetic improvement, future research approaches include investigating transcriptional divergence processes, enhancing genetic resources, and incorporating CRISPR-Cas9 technologies.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Genoma de Planta , Glycine max , Glycine max/genética , Edição de Genes/métodos , Genômica/métodos , Melhoramento Vegetal/métodos , Polimorfismo de Nucleotídeo Único , Estudo de Associação Genômica Ampla
14.
Cell Rep ; 43(9): 114702, 2024 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-39217613

RESUMO

Representation of the environment by hippocampal populations is known to drift even within a familiar environment, which could reflect gradual changes in single-cell activity or result from averaging across discrete switches of single neurons. Disambiguating these possibilities is crucial, as they each imply distinct mechanisms. Leveraging change point detection and model comparison, we find that CA1 population vectors decorrelate gradually within a session. In contrast, individual neurons exhibit predominantly step-like emergence and disappearance of place fields or sustained changes in within-field firing. The changes are not restricted to particular parts of the maze or trials and do not require apparent behavioral changes. The same place fields emerge, disappear, and reappear across days, suggesting that the hippocampus reuses pre-existing assemblies, rather than forming new fields de novo. Our results suggest an internally driven perpetual step-like reorganization of the neuronal assemblies.


Assuntos
Hipocampo , Animais , Hipocampo/fisiologia , Hipocampo/citologia , Neurônios/fisiologia , Masculino , Região CA1 Hipocampal/fisiologia , Região CA1 Hipocampal/citologia , Camundongos , Modelos Neurológicos , Potenciais de Ação/fisiologia , Rede Nervosa/fisiologia , Camundongos Endogâmicos C57BL
15.
Colloids Surf B Biointerfaces ; 244: 114182, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-39216441

RESUMO

Abnormal amyloid ß-protein (Aß42) fibrillation is a key event in Alzheimer's disease (AD), and photodynamic therapy (PDT) possesses great potential in modulating Aß42 self-assembly. However, the poor blood-brain barrier (BBB) penetration, low biocompatibility, and limited tissue penetration depth of existing photosensitizers limit the progress of photo-oxidation strategies. In this paper, novel indocyanine green-modified graphene quantum dot nano-assemblies (NBGQDs-ICGs) were synthesized based on a molecular assembly strategy of electrostatic interactions for PDT inhibition of Aß42 self-assembly process and decomposition of preformed fibrils under near-infrared light. Combining the small-size structure of graphene quantum dots and the near-infrared light-responsive properties of ICGs, the NBGQDs-ICGs could achieve BBB penetration under 808 nm irradiation. More importantly, the neuroprotective mechanism of NBGQDs-ICG was studied for the first time by AFM, which effectively weakened the adhesion of Aß42 aggregates to the cell surface by blocking the interaction between Aß42 and the cell membrane, and restored the mechanical stability and adhesion of the neuron membrane. Meanwhile, NBGQDs-ICG promoted phagocytosis of Aß42 by microglia. In addition, the good biocompatibility and stability ensured the biosafety of NBGQDs-ICG in future clinical applications. We anticipate that such multifunctional nanocomponents may provide promising avenues for the development of novel AD inhibitors.


Assuntos
Peptídeos beta-Amiloides , Barreira Hematoencefálica , Pontos Quânticos , Peptídeos beta-Amiloides/metabolismo , Peptídeos beta-Amiloides/química , Barreira Hematoencefálica/metabolismo , Barreira Hematoencefálica/efeitos dos fármacos , Pontos Quânticos/química , Humanos , Animais , Grafite/química , Grafite/farmacologia , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Tamanho da Partícula , Verde de Indocianina/química , Verde de Indocianina/farmacologia , Fagocitose/efeitos dos fármacos , Carbono/química , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Propriedades de Superfície
16.
Talanta ; 280: 126722, 2024 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-39186860

RESUMO

Photodynamic therapy (PDT) has attracted widespread attention as a novel non-invasive anticancer approach. However, the diminished photosensitivity and limited oxygen exposure caused by the aggregation of traditional photosensitizers greatly impair its overall therapeutic efficacy. Herein, a series of water-soluble aggregation-induced emission luminogens (AIEgens) with triphenylamine as skeleton were synthesized and exhibited bright Near-infrared (NIR) emission and strong reactive oxygen species (ROS) generation. Through host-guest complexation between the multicharged triphenylamine units on AIEgens and cucurbit[10]uril (CB[10]) host molecule, supramolecular nanoassemblies were constructed and exhibited negligible phototoxicity to normal cells due to their limited oxygen contact. In contrast, the efficient release of AIEgens from nanoassemblies through competitive binding of overexpressed peptides in cancer cells with CB[10], enabled the full exploitation of the photosensitivity of AIEgens to produce highly efficient ROS, achieving selective ablation of cancer cells. Moreover, due to the restriction of intramolecular motion (RIM) upon anchored on organelle membranes through electrostatic interactions, the cationic AIEgens with weak fluorescence in physiological environment exhibited intense fluorescence emission, thus realizing imaging-guided PDT. This work may open up an avenue for the development of simple and feasible smart responsive nanomaterials for cancer treatment using supramolecular host-guest complexation strategy.


Assuntos
Fotoquimioterapia , Fármacos Fotossensibilizantes , Espécies Reativas de Oxigênio , Humanos , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/síntese química , Espécies Reativas de Oxigênio/metabolismo , Imagem Óptica , Sobrevivência Celular/efeitos dos fármacos , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/síntese química , Neoplasias/tratamento farmacológico , Neoplasias/diagnóstico por imagem , Neoplasias/patologia , Linhagem Celular Tumoral , Corantes Fluorescentes/química , Corantes Fluorescentes/síntese química , Imidazóis/química , Imidazóis/farmacologia , Compostos de Anilina/química , Compostos de Anilina/farmacologia , Hidrocarbonetos Aromáticos com Pontes/química , Hidrocarbonetos Aromáticos com Pontes/farmacologia
17.
Cell Stress Chaperones ; 29(5): 626-640, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39142378

RESUMO

The heat shock protein 90 kDa (Hsp90) chaperone machinery plays a crucial role in maintaining cellular homeostasis. Beyond its traditional role in protein folding, Hsp90 is integral to key pathways influencing cellular function in health and disease. Hsp90 operates through the modular assembly of large multiprotein complexes, with their composition, stability, and localization adapting to the cell's needs. Its functional dynamics are finely tuned by ligand binding and post-translational modifications (PTMs). Here, we discuss how to disentangle the intricacies of the complex code that governs the crosstalk between dynamics, binding, PTMs, and the functions of the Hsp90 machinery using computer-based approaches. Specifically, we outline the contributions of computational and theoretical methods to the understanding of Hsp90 functions, ranging from providing atomic-level insights into its dynamics to clarifying the mechanisms of interactions with protein clients, cochaperones, and ligands. The knowledge generated in this framework can be actionable for the design and development of chemical tools and drugs targeting Hsp90 in specific disease-associated cellular contexts. Finally, we provide our perspective on how computation can be integrated into the study of the fine-tuning of functions in the highly complex Hsp90 landscape, complementing experimental methods for a comprehensive understanding of this important chaperone system.


Assuntos
Proteínas de Choque Térmico HSP90 , Proteínas de Choque Térmico HSP90/metabolismo , Proteínas de Choque Térmico HSP90/química , Humanos , Processamento de Proteína Pós-Traducional , Chaperonas Moleculares/metabolismo , Chaperonas Moleculares/química , Ligação Proteica , Animais , Ligantes
18.
Int J Biol Macromol ; 278(Pt 1): 134556, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39128762

RESUMO

Structural insight eludes on how full-length gelsolin depolymerizes and caps filamentous (F-)actin, while the same entity can nucleate polymerization of G-actins. Analyzing small angle X-ray scattering (SAXS) data, we deciphered assemblies which enable these contrasting processes. Mixing Ca2+-gelsolin with F-actin in high salt F-buffer resulted in depolymerization of ordered F-actin rods to smaller sized species which became monodispersed upon dialysis with low salt G-buffer. These entities were the ternary (GA2) and binary (GA) complexes of gelsolin and actin with radius of gyration and maximum linear dimension of 4.55 and 4.68 nm, and 15 and 16 nm, respectively. Using size exclusion chromatography in-line with SAXS, we confirmed that initially GA and GA2 species are formed as seen upon depolymerization of F-actin followed by dialysis. Interestingly, while GA2 could seed formation of native-like F-actin in both G- and F-buffer, GA failed in G-buffer. Thus, GA2 and GA are the central species formed via depolymerization or towards nucleation. SAXS profile referenced modeling revealed that: 1) in GA, actin is bound to the C-terminal half of gelsolin, and 2) in GA2, second actin binds to the open N-terminal half accompanied by dramatic rearrangements across g1-g2 and g3-g4 linkers.


Assuntos
Actinas , Cálcio , Gelsolina , Espalhamento a Baixo Ângulo , Difração de Raios X , Gelsolina/química , Actinas/química , Cálcio/química , Modelos Moleculares , Ligação Proteica , Animais , Conformação Proteica
19.
Angew Chem Int Ed Engl ; 63(39): e202405868, 2024 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-38977413

RESUMO

The consequences of intramolecular ionic interactions in determining the reactivity of functional groups are of interest because they provide insights into how nature deploys seemingly reactive functionalities to be rather ubiquitous. Of specific interest are the quaternary ammonium ions in lipids. In this work, we investigate the effect of intramolecular electrostatic interactions in zwitterionic functionalities by judiciously incorporating them as leaving groups at the α-position of α,ß-unsaturated ester-based lipid head groups. We find that electrostatic stabilization indeed plays a critical role in both the reaction kinetics with nucleophiles and the thermodynamics of lipid formation. We further leverage these findings to fabricate both triggerable assembly and disassembly of liposomal supramolecular assemblies in the presence of nucleophiles.

20.
Chemistry ; 30(52): e202401656, 2024 Sep 16.
Artigo em Inglês | MEDLINE | ID: mdl-38969621

RESUMO

Adamantane-type organotin sulfide clusters were recently shown to react with coinage metal phosphine complexes under replacement of an organic substituent by a metal-phosphine unit. An extension of such studies involving the silicon-based congener [(PhSi)4S6] (A) revealed that the cluster core will be partly disassembled and a {PhSi} moiety is replaced by a coinage metal phosphine complex to form [(Et3PAg)3(PhSi)3S6] (B) and [Na2(thf)2.33][(Me3PCu)(PhSi)3S6] (C). Herein, we present an extension of this work upon variation of the reactants and reaction conditions. Besides the isolation of crystalline precursor complexes [CuCl(PMe2Ph)3] (1) and [AgCl(PMe2Ph)2]2 (2), the study addresses reactions of A with AgCl and a phosphine ligand in CH2Cl2, upon which A is completely disassembled to form [(Ph3P)3Ag(µ-S)SiCl2Ph] (3). In another case a CH2 group, most likely stemming from CH2Cl2, was attached to the ligand, thus generating [{PhCl(S)SiSCH2P(Ph2)CH2CH2}2] (4). Upon using CuCl and 1,4-bis(diphenylphosphino)butane (dppb) we isolated the phosphine-bridged analog of B, [{(dppbCu2)CuP(Ph2)(CH2CH2)(PhSi)3S6}2] (5). In order to receive the yet elusive silver homolog of C, we used PMe2Ph as a bulkier ligand. This way we generated a 2D coordination polymer of the desired composition, [Na2(thf)1.5][(Me2PhPAg)(PhSi)3S6] (6). UV-visible spectra of 6 indicated a bandgap of 3.89 eV, thus blue-shifted in regards to B and C.

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