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1.
Bioinspir Biomim ; 19(5)2024 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-38959906

RESUMO

Inspired by the protective armors in nature, composites with asymmetric 3D articulated tiles attached to a soft layer are designed and fabricated via a multi-material 3D printer. The bending resistance of the new designs are characterized via three-point bending experiments. Bending rigidity, strength, and final deflection of the designs are quantified and compared when loaded in two different in-plane and two different out-of-plane directions. It is found that in general, the designs with articulated tiles show direction-dependent bending behaviors with significantly increased bending rigidity, strength, and deflection to final failure in certain loading directions, as is attributed to the asymmetric tile articulation (asymmetric about the mid-plane of tiles) and an interesting sliding-induced auxetic effect. Analytical, numerical, and experimental analyses are conducted to unveil the underlying mechanisms.


Assuntos
Materiais Biomiméticos , Impressão Tridimensional , Teste de Materiais , Biomimética/métodos
2.
J Mater Chem B ; 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39011592

RESUMO

Aiming to decrease the recurrence of tumors and achieve patient satisfaction, the elicitation of immunotherapy and its integrated synergistic employment is a bright new direction in oncotherapy, yet an emergently challenging task. In particular, tumor-associated macrophage (TAM) regulation though light-induced photodynamic and photothermal therapy (PDT and PTT) is regarded as a powerful approach, which focuses on the systemic immune system instead of the tumor itself. Herein, this study reports an acceptor-donor-acceptor (A-D-A) aggregation-induced emission luminogen (AIEgen), named TPA-2CN, which was applied as a photosensitizer (PS) and photothermal agent (PTA). Attributed to its A-D-A structure and AIE properties, TPA-2CN exhibits a high molar absorption coefficient and acts as a perfect template in regulating radiative and nonradiative transitions, which mainly utilize excited energy. The generation of type I reactive oxygen promoted its application in hypoxic tumor sites and the combination of hyperpyrexia forcefully induces macrophages to polarize towards the immune response M1 phenotype. In in vitro and in vivo, the successful reversion and reprogramming of the immune microenvironment was impressively proved. This method optimally concentrated immune therapy, PDT and PTT as one and exhibited excellent synergistic therapeutic effects with good biosafety.

3.
Nano Lett ; 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38973752

RESUMO

Electrocatalytic nitrate reduction is an efficient way to produce ammonia sustainably. Herein, we rationally designed a copper metalloporphyrin-based hydrogen-bonded organic framework (HOF-Cu) through molecular engineering strategies for electrochemical nitrate reduction. As a result, the state-of-the-art HOF-Cu catalyst exhibits high NH3 Faradaic efficiency of 93.8%, and the NH3 production rate achieves a superior activity of 0.65 mmol h-1 cm-2. The in situ electrochemical spectroscopic combined with density functional theory calculations reveals that the dispersed Cu promotes the adsorption of NO3- and the mechanism is followed by deoxidation of NO3- to *NO and accompanied by deep hydrogenation. The generated *H participates in the deep hydrogenation of intermediate with fast kinetics as revealed by operando electrochemical impedance spectroscopy, and the competing hydrogen evolution reaction is suppressed. This research provides a promising approach to the conversion of nitrate to ammonia, maintaining the nitrogen balance in the atmosphere.

4.
J Org Chem ; 89(12): 9103-9109, 2024 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-38842047

RESUMO

A brief, practical catalytic process for the production of optically active γ-functionalized alcohols from relevant alkenes has been developed by using a robust Mn(III)/air/(Me2SiH)2O catalytic system combined with lipase-catalyzed kinetic resolution. This approach demonstrates exceptional tolerance toward proximal functional groups present on alkenes, enabling the achievement of high yields and exclusive enantioselectivity. Under this sequential catalytic system, the chiral alkene precursors can also be converted into γ-functionalized alcohols and related acetates as separable single enantiomers.

5.
Nat Commun ; 15(1): 3711, 2024 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-38697966

RESUMO

The LAT1-4F2hc complex (SLC7A5-SLC3A2) facilitates uptake of essential amino acids, hormones and drugs. Its dysfunction is associated with many cancers and immune/neurological disorders. Here, we apply native mass spectrometry (MS)-based approaches to provide evidence of super-dimer formation (LAT1-4F2hc)2. When combined with lipidomics, and site-directed mutagenesis, we discover four endogenous phosphatidylethanolamine (PE) molecules at the interface and C-terminus of both LAT1 subunits. We find that interfacial PE binding is regulated by 4F2hc-R183 and is critical for regulation of palmitoylation on neighbouring LAT1-C187. Combining native MS with mass photometry (MP), we reveal that super-dimerization is sensitive to pH, and modulated by complex N-glycans on the 4F2hc subunit. We further validate the dynamic assemblies of LAT1-4F2hc on plasma membrane and in the lysosome. Together our results link PTM and lipid binding with regulation and localisation of the LAT1-4F2hc super-dimer.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Cadeia Pesada da Proteína-1 Reguladora de Fusão , Transportador 1 de Aminoácidos Neutros Grandes , Lipoilação , Proteínas de Membrana , Fosfatidiletanolaminas , Humanos , Transportador 1 de Aminoácidos Neutros Grandes/metabolismo , Transportador 1 de Aminoácidos Neutros Grandes/genética , Fosfatidiletanolaminas/metabolismo , Lisossomos/metabolismo , Membrana Celular/metabolismo , Sistema y+ de Transporte de Aminoácidos/metabolismo , Sistema y+ de Transporte de Aminoácidos/genética , Células HEK293 , Multimerização Proteica , Ligação Proteica , Espectrometria de Massas , Mutagênese Sítio-Dirigida , Concentração de Íons de Hidrogênio
6.
Artigo em Inglês | MEDLINE | ID: mdl-38726971

RESUMO

OBJECTIVE: To compare the rehabilitative efficacy of different physiotherapy scoliosis-specific exercises (PSSE) for adolescent idiopathic scoliosis (AIS) using a network meta-analysis. DESIGN: PubMed, Cochrane Library, Web of Science, EMBASE, VIP Database for Chinese Technical Periodicals, China National Knowledge Infrastructure, Chinese Biomedical Literature Database, and Wan Fang Data were searched until October 2023. Meta-analysis and network meta-analysis were conducted using RevMan 5.4 and R4.3.1. This study follows the PRISMA statement and was registered on the PROSPERO platform (No. CRD42022379206). RESULTS: Seventeen RCTs involving 857 patients were included. The meta-analysis showed that PSSE therapy improved Cobb's angle than conventional rehabilitation therapy (standardized mean difference [SMD] = -0.7; 95% confidence interval [CI] = -0.95, -0.44; p = 0.001), angle of trunk rotation (ATR; SMD = -1.05; 95% CI = -1.52, -0.58; p < 0.001), and quality of life (QoL; SMD = 0.61; 95% CI = 0.16, 1.07; p < 0.001). Network meta-analysis showed that Schroth + Scientific Exercise Approach to Scoliosis (SEAS) was the most effective in improving Cobb angle and ATR, while Schroth alone was most effective in improving the QoL. CONCLUSION: The combination of Schroth and SEAS improved the body posture and trunk deformity in patients with AIS, while Schroth alone improved the QoL. The effectiveness of combining different PSSE techniques supports future evidence-based research on AIS treatment.

7.
Small ; : e2400654, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38752582

RESUMO

Benefit from the deeper penetration of mechanical wave, ultrasound (US)-based sonodynamic therapy (SDT) executes gratifying efficacy in treating deep-seated tumors. Nevertheless, the complicated mechanism of SDT undeniably hinders the exploration of ingenious sonosensitizers. Herein, a receptor engineering strategy of aggregation-induced emission (AIE) sonosensitizers (TPA-Tpy) with acceptor (A)-donor (D)-A' structure is proposed, which inspects the effect of increased cationizations on US sensitivity. Under US stimulation, enhanced cationization in TPA-Tpy improves intramolecular charge transfer (ICT) and accelerates charge separation, which possesses a non-negligible promotion in type I reactive oxygen species (ROS) production. Moreover, abundant ROS-mediated mitochondrial oxidative stress triggers satisfactory immunogenic cell death (ICD), which further promotes the combination of SDT and ICD. Subsequently, subacid pH-activated nanoparticles (TPA-Tpy NPs) are constructed with charge-converting layer (2,3-dimethylmaleic anhydride-poly (allylamine hydrochloride)-polyethylene glycol (DMMA-PAH-PEG)) and TPA-Tpy, achieving the controllable release of sonosensitizers. In vivo, TPA-Tpy-mediated SDT effectively initiates the surface-exposed of calreticulin (ecto-CRT), dendritic cells (DCs) maturation, and CD8+ T cell infiltration rate through enhanced ROS production, achieving suppression and ablation of primary and metastatic tumors. This study provides new opinions in regulating acceptors with eminent US sensitization, and brings a novel ICD sono-inducer based on SDT to realize superior antitumor effect.

8.
Structure ; 32(6): 654-661.e3, 2024 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-38579705

RESUMO

There are three key components at the core of the mpox virus (MPXV) DNA polymerase holoenzyme: DNA polymerase F8, processivity factors A22, and the Uracil-DNA glycosylase E4. The holoenzyme is recognized as a vital antiviral target because MPXV replicates in the cytoplasm of host cells. Nucleotide analogs such as cidofovir and cytarabine (Ara-C) have shown potential in curbing MPXV replication and they also display promise against other poxviruses. However, the mechanism behind their inhibitory effects remains unclear. Here, we present the cryo-EM structure of the DNA polymerase holoenzyme F8/A22/E4 bound with its competitive inhibitor Ara-C-derived cytarabine triphosphate (Ara-CTP) at an overall resolution of 3.0 Å and reveal its inhibition mechanism. Ara-CTP functions as a direct chain terminator in proximity to the deoxycytidine triphosphate (dCTP)-binding site. The extra hydrogen bond formed with Asn665 makes it more potent in binding than dCTP. Asn665 is conserved among eukaryotic B-family polymerases.


Assuntos
Microscopia Crioeletrônica , DNA Polimerase Dirigida por DNA , Modelos Moleculares , DNA Polimerase Dirigida por DNA/química , DNA Polimerase Dirigida por DNA/metabolismo , Sítios de Ligação , Ligação Proteica , Holoenzimas/química , Holoenzimas/metabolismo , Proteínas Virais/química , Proteínas Virais/metabolismo , Antivirais/química , Antivirais/farmacologia , Poxviridae/química , Poxviridae/genética , Poxviridae/metabolismo , Citidina Trifosfato/metabolismo , Citidina Trifosfato/química
9.
Nat Commun ; 15(1): 3036, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38589439

RESUMO

The Alanine-Serine-Cysteine transporter 1 (Asc-1 or SLC7A10) forms a crucial heterodimeric transporter complex with 4F2hc (SLC3A2) through a covalent disulfide bridge. This complex enables the sodium-independent transport of small neutral amino acids, including L-Alanine (L-Ala), Glycine (Gly), and D-Serine (D-Ser), within the central nervous system (CNS). D-Ser and Gly are two key endogenous glutamate co-agonists that activate N-methyl-d-aspartate (NMDA) receptors by binding to the allosteric site. Mice deficient in Asc-1 display severe symptoms such as tremors, ataxia, and seizures, leading to early postnatal death. Despite its physiological importance, the functional mechanism of the Asc-1-4F2hc complex has remained elusive. Here, we present cryo-electron microscopy (cryo-EM) structures of the human Asc-1-4F2hc complex in its apo state, D-Ser bound state, and L-Ala bound state, resolved at 3.6 Å, 3.5 Å, and 3.4 Å, respectively. Through detailed structural analysis and transport assays, we uncover a comprehensive alternating access mechanism that underlies conformational changes in the complex. In summary, our findings reveal the architecture of the Asc-1 and 4F2hc complex and provide valuable insights into substrate recognition and the functional cycle of this essential transporter complex.


Assuntos
Proteínas de Membrana Transportadoras , Serina , Camundongos , Humanos , Animais , Microscopia Crioeletrônica , Serina/metabolismo , Proteínas de Membrana Transportadoras/genética , Glicina , Cisteína
10.
Sci Total Environ ; 929: 172701, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38657811

RESUMO

This study evaluated the effects of cadmium (Cd) exposure on the passive and active lethal efficiency of Beauveria bassiana (Bb) to Lymantria dispar larvae and analyzed the corresponding mechanism from mycelial vegetative growth, fungal and host nutrient competition, and fungal spore performance. The results showed that the passive lethal efficiency of Bb to Cd-exposed L. dispar larvae was significantly higher than that of larvae not exposed to Cd. After Bb infection, the fungal biomass in living larvae and the mycelium encapsulation index of dead larvae were significantly decreased under Cd exposure. Cd exposure damaged the mycelial structure, as well as inhibited the mycelial growth and sporulation quantity. A total of 15 and 39 differentially accumulated mycotoxin metabolites were identified in Bb mycelia treated with low Cd and high Cd, respectively, and the contents of these differentially accumulated mycotoxins in the low Cd and high Cd treatment groups were overall lower than those in the control group. Nutrient content and energy metabolism-related gene expression were significantly decreased in Cd-exposed larvae, both before and after Bb infection. Trehalose supplementation alleviated the nutritional deficiency of larvae under the combined treatment of Cd and Bb and decreased the larval susceptibility to Bb. Compared with untreated Bb, the lethal efficiency of low Cd-exposed Bb to larvae increased significantly, while high Cd-exposed Bb was significantly less lethal to larvae. Cd exposure promoted at low concentrations but inhibited the hydrophobicity and adhesion of spores at higher concentrations. Spore germination rate and stress resistance of Bb decreased significantly under the treatment of both Cd concentrations. Taken together, heavy metals can be regarded as an abiotic environmental factor that directly affects the lethal efficiency of Bb to insect pests.


Assuntos
Beauveria , Cádmio , Larva , Mariposas , Beauveria/fisiologia , Animais , Cádmio/toxicidade , Mariposas/fisiologia , Controle Biológico de Vetores , Ecossistema , Agricultura Florestal , Esporos Fúngicos/efeitos dos fármacos , Micotoxinas , Agricultura/métodos , Complexo de Mariposas do Gênero Lymantria
11.
World J Gastrointest Oncol ; 16(3): 991-1005, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38577443

RESUMO

BACKGROUND: The precise role of mitochondrial carrier homolog 2 (MTCH2) in promoting malignancy in gastric mucosal cells and its involvement in gastric cancer cell metastasis have not been fully elucidated. AIM: To determine the role of MTCH2 in gastric cancer. METHODS: We collected 65 samples of poorly differentiated gastric cancer tissue and adjacent tissues, constructed MTCH2-overexpressing and MTCH2-knockdown cell models, and evaluated the proliferation, migration, and invasion of human gastric epithelial cells (GES-1) and human gastric cancer cells (AGS) cells. The mitochondrial membrane potential (MMP), mitochondrial permeability transformation pore (mPTP) and ATP fluorescence probe were used to detect mitochondrial function. Mitochondrial function and ATP synthase protein levels were detected via Western blotting. RESULTS: The expression of MTCH2 and ATP2A2 in gastric cancer tissues was significantly greater than that in adjacent tissues. Overexpression of MTCH2 promoted colony formation, invasion, migration, MMP expression and ATP production in GES-1 and AGS cells while upregulating ATP2A2 expression and inhibiting cell apoptosis; knockdown of MTCH2 had the opposite effect, promoting overactivation of the mPTP and promoting apoptosis. CONCLUSION: MTCH2 can increase the malignant phenotype of GES-1 cells and promote the proliferation, invasion, and migration of gastric cancer cells by regulating mitochondrial function, providing a basis for targeted therapy for gastric cancer cells.

12.
J Evid Based Dent Pract ; 24(1): 101933, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38448118

RESUMO

OBJECTIVES: Accuracy is a crucial factor when assessing the quality of digital impressions. This systematic review aims to assess the accuracy of intraoral scan (IOS) in obtaining digital impressions of edentulous jaws. METHODS: This systematic review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and was registered in the International Prospective Register of Systematic Reviews (PROSPERO ID: CRD42022382983). A thorough retrieval of 7 electronic databases was undertaken, encompassing MEDLINE (PubMed), Web of Science, EMBASE, Scopus, Cochrane Library, Virtual Health Library, and Open gray, through September 11, 2023. A snowball search was performed by tracing the reference lists of the included studies. The Population, Intervention, Comparison, and Outcome (PICO) question of this systematic review was: "What is the accuracy of intraoral scan in obtaining digital impressions of edentulous arches?" The Modified Methodological Index for Nonrandomized Studies (MINORS) was employed to assess the risk of bias. RESULTS: Among the studies retrieved from databases and manual search, a total of 25 studies were selected for inclusion in this systematic review, including 9 in vivo and 16 in vitro studies. Twenty-one of the included studies utilized the 3D deviation analysis method, while 4 studies employed the linear or angular deviation analysis method. The accuracy results of in vitro studies indicated a trueness range of 20-600 µm and a precision range of 2-700 µm. Results of in vivo studies indicated a trueness range of 40-1380 µm, while the precision results were not reported. CONCLUSION: According to the results of this study, direct digital impressions by IOS cannot replace the conventional impressions of completely edentulous arches in vivo. Edentulous digital impressions by IOS demonstrated poor accuracy in peripheral areas with mobile tissues, such as the soft palate, vestibular sulcus, and sublingual area.

13.
Sci Adv ; 10(13): eadl3685, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38552027

RESUMO

The solute carrier 13 (SLC13) family comprises electrogenic sodium ion-coupled anion cotransporters, segregating into sodium ion-sulfate cotransporters (NaSs) and sodium ion-di- and-tricarboxylate cotransporters (NaDCs). NaS1 and NaDC1 regulate sulfate homeostasis and oxidative metabolism, respectively. NaS1 deficiency affects murine growth and fertility, while NaDC1 affects urinary citrate and calcium nephrolithiasis. Despite their importance, the mechanisms of substrate recognition and transport remain insufficiently characterized. In this study, we determined the cryo-electron microscopy structures of human NaS1, capturing inward-facing and combined inward-facing/outward-facing conformations within a dimer both in apo and sulfate-bound states. In addition, we elucidated NaDC1's outward-facing conformation, encompassing apo, citrate-bound, and N-(p-amylcinnamoyl) anthranilic acid (ACA) inhibitor-bound states. Structural scrutiny illuminates a detailed elevator mechanism driving conformational changes. Notably, the ACA inhibitor unexpectedly binds primarily anchored by transmembrane 2 (TM2), Loop 10, TM11, and TM6a proximate to the cytosolic membrane. Our findings provide crucial insights into SLC13 transport mechanisms, paving the way for future drug design.


Assuntos
Simportadores , Animais , Humanos , Camundongos , Regulação Alostérica , Citratos/metabolismo , Microscopia Crioeletrônica , Sódio/metabolismo , Sulfatos/metabolismo , Simportadores/metabolismo
14.
Br J Clin Pharmacol ; 90(6): 1493-1502, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38500445

RESUMO

AIMS: To investigate the exposure-response (E-R) relationship, including exposure-efficacy and exposure-safety, of ropeginterferon alfa-2b treatment in patients with polycythaemia vera (PV). METHODS: Based on the results of the phase II trial A20-202 regarding ropeginterferon alfa-2b in patients with PV, E-R analyses were performed to evaluate the efficacy and safety of the given dosing regimen. The E-R analyses were based on logistic and linear regression and the relationship between exposure to ropeginterferon alfa-2b and key efficacy and safety variables. The key efficacy variables included complete haematologic response (CHR) and reduction of the driver mutation JAK2V617F. The safety variable was treatment-related adverse events (TRAEs). RESULTS: A clear relationship between the exposure to ropeginterferon alfa-2b and CHR was observed, with an increase in drug exposure resulting in an increased probability of achieving CHR. Similar CHR probabilities were observed in the third and fourth quantiles of the average concentration at Week 24. The results from the exposure-JAK2V617F model indicated that the JAK2V617F allele burden decreased with increasing exposure to ropeginterferon alfa-2b and baseline body surface area. Exposure-safety analysis revealed a risk of AEs associated with transaminase abnormalities, which were not associated with clinical significance. CONCLUSIONS: Our analyses have shown that patients with PV treated with ropeginterferon alfa-2b had an increased probability of achieving CHR and a molecular response with acceptable safety risks at the 250-350-500 µg titration dosing regimen. This study has provided the relevant data for the application of a biologics licence of ropeginterferon alfa-2b for PV treatment in China.


Assuntos
Interferon alfa-2 , Interferon-alfa , Janus Quinase 2 , Policitemia Vera , Polietilenoglicóis , Proteínas Recombinantes , Humanos , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/efeitos adversos , Proteínas Recombinantes/uso terapêutico , Interferon-alfa/administração & dosagem , Interferon-alfa/efeitos adversos , Interferon-alfa/uso terapêutico , Polietilenoglicóis/efeitos adversos , Polietilenoglicóis/administração & dosagem , Interferon alfa-2/administração & dosagem , Interferon alfa-2/efeitos adversos , Policitemia Vera/tratamento farmacológico , Policitemia Vera/genética , Masculino , Feminino , Pessoa de Meia-Idade , Janus Quinase 2/genética , Resultado do Tratamento , Relação Dose-Resposta a Droga , Idoso , Adulto
15.
Mol Plant Pathol ; 25(3): e13425, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38462784

RESUMO

Phosphatases are important regulators of protein phosphorylation and various cellular processes, and they serve as counterparts to kinases. In this study, our comprehensive analysis of oomycete complete proteomes unveiled the presence of approximately 3833 phosphatases, with most species estimated to have between 100 and 300 putative phosphatases. Further investigation of these phosphatases revealed a significant increase in protein serine/threonine phosphatases (PSP) within oomycetes. In particular, we extensively studied the metallo-dependent protein phosphatase (PPM) within the PSP family in the model oomycete Phytophthora sojae. Our results showed notable differences in the expression patterns of PPMs throughout 10 life stages of P. sojae, indicating their vital roles in various stages of oomycete pathogens. Moreover, we identified 29 PPMs in P. sojae, and eight of them possessed accessory domains in addition to phosphate domains. We investigated the biological function of one PPM protein with an extra PH domain (PPM1); this protein exhibited high expression levels in both asexual developmental and infectious stages. Our analysis confirmed that PPM1 is indeed an active protein phosphatase, and its accessory domain does not affect its phosphatase activity. To delve further into its function, we generated knockout mutants of PPM1 and validated its essential roles in mycelial growth, sporangia and oospore production, as well as infectious stages. To the best of our knowledge, this study provides the first comprehensive inventory of phosphatases in oomycetes and identifies an important phosphatase within the expanded serine/threonine phosphatase group in oomycetes.


Assuntos
Oomicetos , Phytophthora , Proteoma/metabolismo , Phytophthora/metabolismo , Fosfoproteínas Fosfatases/genética , Fosfoproteínas Fosfatases/metabolismo , Serina/metabolismo
18.
Elife ; 122024 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-38236718

RESUMO

As the genome is organized into a three-dimensional structure in intracellular space, epigenomic information also has a complex spatial arrangement. However, most epigenetic studies describe locations of methylation marks, chromatin accessibility regions, and histone modifications in the horizontal dimension. Proper spatial epigenomic information has rarely been obtained. In this study, we designed spatial chromatin accessibility sequencing (SCA-seq) to resolve the genome conformation by capturing the epigenetic information in single-molecular resolution while simultaneously resolving the genome conformation. Using SCA-seq, we are able to examine the spatial interaction of chromatin accessibility (e.g. enhancer-promoter contacts), CpG island methylation, and spatial insulating functions of the CCCTC-binding factor. We demonstrate that SCA-seq paves the way to explore the mechanism of epigenetic interactions and extends our knowledge in 3D packaging of DNA in the nucleus.


Assuntos
Cromatina , Epigenômica , Cromatina/genética , Cromossomos , DNA , Sequências Reguladoras de Ácido Nucleico , Metilação de DNA
19.
Adv Mater ; 36(15): e2309604, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38183315

RESUMO

For artificial materials, desired properties often conflict. For example, engineering materials often achieve high energy dissipation by sacrificing resilience and vice versa, or desired auxeticity by losing their isotropy, which limits their performance and applications. To solve these conflicts, a strategy is proposed to create novel mechanical metamaterial via 3D space filling tiles with engaging key-channel pairs, exemplified via auxetic 3D keyed-octahedron-cuboctahedron metamaterials. This metamaterial shows high resilience while achieving large mechanical hysteresis synergistically under large compressive strain. Especially, this metamaterial exhibits ideal isotropy approaching the theoretical limit of isotropic Poisson's ratio, -1, as rarely seen in existing 3D mechanical metamaterials. In addition, the new class of metamaterials provides wide tunability on mechanical properties and behaviors, including an unusual coupled auxeticity and twisting behavior under normal compression. The designing methodology is illustrated by the integral of numerical modeling, theoretical analysis, and experimental characterization. The new mechanical metamaterials have broad applications in actuators and dampers, soft robotics, biomedical materials, and engineering materials/systems for energy dissipation.

20.
Nat Struct Mol Biol ; 31(1): 68-81, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38177671

RESUMO

The Mpox pandemic, caused by the Mpox virus (or monkeypox virus, MPXV), has gained global attention. The D5 protein, a putative helicase-primase found in MPXV, plays a vital role in viral replication and genome uncoating. Here we determined multiple cryo-EM structures of full-length hexameric D5 in diverse states. These states were captured during ATP hydrolysis while moving along the single-stranded DNA (ssDNA) track. Through comprehensive structural analysis combined with the helicase activity system, we revealed that when the primase domain is truncated or the interaction between the primase and helicase domains is disrupted, the double-stranded DNA (dsDNA) unwinds into ssDNA, suggesting a critical regulatory role of the primase domain. Two transition states bound with ssDNA substrate during unwinding reveals that two ATP molecules were consumed to drive DNA moving forward two nucleotides. Collectively, our findings shed light on the molecular mechanism that links ATP hydrolysis to the DNA unwinding in poxviruses.


Assuntos
DNA Primase , Monkeypox virus , DNA Primase/química , DNA Primase/genética , DNA Primase/metabolismo , Monkeypox virus/genética , Monkeypox virus/metabolismo , DNA Helicases/metabolismo , DNA/química , DNA de Cadeia Simples , Trifosfato de Adenosina/metabolismo
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