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1.
bioRxiv ; 2024 Aug 17.
Artigo em Inglês | MEDLINE | ID: mdl-39185226

RESUMO

Complex structural and functional changes occurring in typical and atypical development necessitate multidimensional approaches to better understand the risk of developing psychopathology. Here, we simultaneously examined structural and functional brain network patterns in relation to dimensions of psychopathology in the Adolescent Brain Cognitive Development dataset. Several components were identified, recapitulating the psychopathology hierarchy, with the general psychopathology ( p ) factor explaining most covariance with multimodal imaging features, while the internalizing, externalizing, and neurodevelopmental dimensions were each associated with distinct morphological and functional connectivity signatures. Connectivity signatures associated with the p factor and neurodevelopmental dimensions followed the sensory-to-transmodal axis of cortical organization, which is related to the emergence of complex cognition and risk for psychopathology. Results were consistent in two separate data subsamples, supporting generalizability, and robust to variations in analytical parameters. Our findings help in better understanding biological mechanisms underpinning dimensions of psychopathology, and could provide brain-based vulnerability markers.

2.
Molecules ; 29(15)2024 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-39124901

RESUMO

Bromodomain-containing protein 9 (BRD9) is a key player in chromatin remodeling and gene expression regulation, and it is closely associated with the development of various diseases, including cancers. Recent studies have indicated that inhibition of BRD9 may have potential value in the treatment of certain cancers. Molecular dynamics (MD) simulations, Markov modeling and principal component analysis were performed to investigate the binding mechanisms of allosteric inhibitor POJ and orthosteric inhibitor 82I to BRD9 and its allosteric regulation. Our results indicate that binding of these two types of inhibitors induces significant structural changes in the protein, particularly in the formation and dissolution of α-helical regions. Markov flux analysis reveals notable changes occurring in the α-helicity near the ZA loop during the inhibitor binding process. Calculations of binding free energies reveal that the cooperation of orthosteric and allosteric inhibitors affects binding ability of inhibitors to BRD9 and modifies the active sites of orthosteric and allosteric positions. This research is expected to provide new insights into the inhibitory mechanism of 82I and POJ on BRD9 and offers a theoretical foundation for development of cancer treatment strategies targeting BRD9.


Assuntos
Cadeias de Markov , Simulação de Dinâmica Molecular , Ligação Proteica , Fatores de Transcrição , Regulação Alostérica , Fatores de Transcrição/metabolismo , Fatores de Transcrição/química , Fatores de Transcrição/antagonistas & inibidores , Humanos , Sítios de Ligação , Análise de Componente Principal , Termodinâmica , Proteínas que Contêm Bromodomínio
3.
Molecules ; 29(14)2024 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-39064955

RESUMO

Inhibiting MDM2-p53 interaction is considered an efficient mode of cancer treatment. In our current study, Gaussian-accelerated molecular dynamics (GaMD), deep learning (DL), and binding free energy calculations were combined together to probe the binding mechanism of non-peptide inhibitors K23 and 0Y7 and peptide ones PDI6W and PDI to MDM2. The GaMD trajectory-based DL approach successfully identified significant functional domains, predominantly located at the helixes α2 and α2', as well as the ß-strands and loops between α2 and α2'. The post-processing analysis of the GaMD simulations indicated that inhibitor binding highly influences the structural flexibility and collective motions of MDM2. Calculations of molecular mechanics-generalized Born surface area (MM-GBSA) and solvated interaction energy (SIE) not only suggest that the ranking of the calculated binding free energies is in agreement with that of the experimental results, but also verify that van der Walls interactions are the primary forces responsible for inhibitor-MDM2 binding. Our findings also indicate that peptide inhibitors yield more interaction contacts with MDM2 compared to non-peptide inhibitors. Principal component analysis (PCA) and free energy landscape (FEL) analysis indicated that the piperidinone inhibitor 0Y7 shows the most pronounced impact on the free energy profiles of MDM2, with the piperidinone inhibitor demonstrating higher fluctuation amplitudes along primary eigenvectors. The hot spots of MDM2 revealed by residue-based free energy estimation provide target sites for drug design toward MDM2. This study is expected to provide useful theoretical aid for the development of selective inhibitors of MDM2 family members.


Assuntos
Aprendizado Profundo , Simulação de Dinâmica Molecular , Peptídeos , Ligação Proteica , Proteínas Proto-Oncogênicas c-mdm2 , Proteínas Proto-Oncogênicas c-mdm2/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-mdm2/química , Proteínas Proto-Oncogênicas c-mdm2/metabolismo , Peptídeos/química , Peptídeos/farmacologia , Humanos , Termodinâmica , Sítios de Ligação , Distribuição Normal
4.
Molecules ; 29(11)2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38893554

RESUMO

CDK6 plays a key role in the regulation of the cell cycle and is considered a crucial target for cancer therapy. In this work, conformational transitions of CDK6 were identified by using Gaussian accelerated molecular dynamics (GaMD), deep learning (DL), and free energy landscapes (FELs). DL finds that the binding pocket as well as the T-loop binding to the Vcyclin protein are involved in obvious differences of conformation contacts. This result suggests that the binding pocket of inhibitors (LQQ and AP9) and the binding interface of CDK6 to the Vcyclin protein play a key role in the function of CDK6. The analyses of FELs reveal that the binding pocket and the T-loop of CDK6 have disordered states. The results from principal component analysis (PCA) indicate that the binding of the Vcyclin protein affects the fluctuation behavior of the T-loop in CDK6. Our QM/MM-GBSA calculations suggest that the binding ability of LQQ to CDK6 is stronger than AP9 with or without the binding of the Vcyclin protein. Interaction networks of inhibitors with CDK6 were analyzed and the results reveal that LQQ contributes more hydrogen binding interactions (HBIs) and hot interaction spots with CDK6. In addition, the binding pocket endures flexibility changes from opening to closing states and the Vcyclin protein plays an important role in the stabilizing conformation of the T-loop. We anticipate that this work could provide useful information for further understanding the function of CDK6 and developing new promising inhibitors targeting CDK6.


Assuntos
Quinase 6 Dependente de Ciclina , Aprendizado Profundo , Simulação de Dinâmica Molecular , Ligação Proteica , Quinase 6 Dependente de Ciclina/metabolismo , Quinase 6 Dependente de Ciclina/química , Quinase 6 Dependente de Ciclina/antagonistas & inibidores , Humanos , Conformação Proteica , Sítios de Ligação , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/farmacologia , Análise de Componente Principal , Termodinâmica , Distribuição Normal
5.
Sci Adv ; 10(24): eado2037, 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38875326

RESUMO

Activatable near-infrared (NIR) imaging in the NIR-II range is crucial for deep tissue bioanalyte tracking. However, designing such probes remains challenging due to the limited availability of general chemical strategies. Here, we introduced a foundational platform for activatable probes, using analyte-triggered smart modulation of the π-conjugation system of a NIR-II-emitting rhodamine hybrid. By tuning the nucleophilicity of the ortho-carboxy moiety, we achieved an electronic effect termed "firm-push-to-open and light-push-to-lock," which enables complete spirocyclization of the probe before sensing and allows for efficient zwitterion formation when the light-pushing aniline carbamate trigger is transformed into a firm-pushing aniline. This platform produces dual-modality NIR-II imaging probes with ~50-fold fluorogenic and activatable photoacoustic signals in live mice, surpassing reported probes with generally below 10-fold activatable signals. Demonstrating generality, we successfully designed probes for hydrogen peroxide (H2O2) and hydrogen sulfide (H2S). We envision a widespread adoption of the chemical platform for designing activatable NIR-II probes across diverse applications.


Assuntos
Corantes Fluorescentes , Animais , Camundongos , Corantes Fluorescentes/química , Imagem Óptica/métodos , Peróxido de Hidrogênio/química , Humanos , Sulfeto de Hidrogênio/análise , Sulfeto de Hidrogênio/química , Técnicas Fotoacústicas/métodos , Raios Infravermelhos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Rodaminas/química
6.
Nat Commun ; 15(1): 5482, 2024 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-38942809

RESUMO

Transition metal-catalyzed asymmetric hydrogenation is one of the most efficient methods for the preparation of chiral α-substituted propionic acids. However, research on this method, employing cleaner earth-abundant metal catalysts, is still insufficient in both academic and industrial contexts. Herein, we report an efficient nickel-catalyzed asymmetric hydrogenation of α-substituted acrylic acids affording the corresponding chiral α-substituted propionic acids with up to 99.4% ee (enantiomeric excess) and 10,000 S/C (substrate/catalyst). In particular, this method can be used to obtain (R)-dihydroartemisinic acid with 99.8:0.2 dr (diastereomeric ratio) and 5000 S/C, which is an essential intermediate for the preparation of the antimalarial drug Artemisinin. The reaction mechanism has been investigated via experiments and DFT (Density Functional Theory) calculations, which indicate that the protonolysis of the C-Ni bond of the key intermediate via an intramolecular proton transfer from the carboxylic acid group of the substrate, is the rate-determining step.

7.
Molecules ; 29(10)2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38792177

RESUMO

The phosphorylation of different sites produces a significant effect on the conformational dynamics of KRAS. Gaussian accelerated molecular dynamics (GaMD) simulations were combined with deep learning (DL) to explore the molecular mechanism of the phosphorylation-mediated effect on conformational dynamics of the GTP-bound KRAS. The DL finds that the switch domains are involved in obvious differences in conformation contacts and suggests that the switch domains play a key role in the function of KRAS. The analyses of free energy landscapes (FELs) reveal that the phosphorylation of pY32, pY64, and pY137 leads to more disordered states of the switch domains than the wild-type (WT) KRAS and induces conformational transformations between the closed and open states. The results from principal component analysis (PCA) indicate that principal motions PC1 and PC2 are responsible for the closed and open states of the phosphorylated KRAS. Interaction networks were analyzed and the results verify that the phosphorylation alters interactions of GTP and magnesium ion Mg2+ with the switch domains. It is concluded that the phosphorylation pY32, pY64, and pY137 tune the activity of KRAS through changing conformational dynamics and interactions of the switch domains. We anticipated that this work could provide theoretical aids for deeply understanding the function of KRAS.


Assuntos
Aprendizado Profundo , Guanosina Trifosfato , Proteínas Proto-Oncogênicas p21(ras) , Humanos , Guanosina Trifosfato/metabolismo , Guanosina Trifosfato/química , Simulação de Dinâmica Molecular , Fosforilação , Análise de Componente Principal , Ligação Proteica , Conformação Proteica , Proteínas Proto-Oncogênicas p21(ras)/química , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética
8.
Molecules ; 29(8)2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38675678

RESUMO

Bromodomain 4 and 9 (BRD4 and BRD9) have been regarded as important targets of drug designs in regard to the treatment of multiple diseases. In our current study, molecular dynamics (MD) simulations, deep learning (DL) and binding free energy calculations are integrated to probe the binding modes of three inhibitors (H1B, JQ1 and TVU) to BRD4 and BRD9. The MD trajectory-based DL successfully identify significant functional function domains, such as BC-loop and ZA-loop. The information from the post-processing analysis of MD simulations indicates that inhibitor binding highly influences the structural flexibility and dynamic behavior of BRD4 and BRD9. The results of the MM-GBSA calculations not only suggest that the binding ability of H1B, JQ1 and TVU to BRD9 are stronger than to BRD4, but they also verify that van der Walls interactions are the primary forces responsible for inhibitor binding. The hot spots of BRD4 and BRD9 revealed by residue-based free energy estimation provide target sites of drug design in regard to BRD4 and BRD9. This work is anticipated to provide useful theoretical aids for the development of selective inhibitors over BRD family members.


Assuntos
Proteínas que Contêm Bromodomínio , Proteínas de Ciclo Celular , Aprendizado Profundo , Simulação de Dinâmica Molecular , Ligação Proteica , Fatores de Transcrição , Fatores de Transcrição/antagonistas & inibidores , Fatores de Transcrição/metabolismo , Fatores de Transcrição/química , Proteínas de Ciclo Celular/antagonistas & inibidores , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/metabolismo , Humanos , Sítios de Ligação , Termodinâmica , Triazóis/química , Triazóis/farmacologia , Azepinas/química , Azepinas/farmacologia , Proteínas Nucleares/metabolismo , Proteínas Nucleares/antagonistas & inibidores , Proteínas Nucleares/química , Simulação de Acoplamento Molecular
9.
Comput Biol Med ; 171: 108037, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38377716

RESUMO

The development of deep learning models for predicting toxicological endpoints has shown great promise, but one of the challenges in the field is the accuracy and interpretability of these models. The bioactive conformation of a compound plays a critical role for it to bind in the target. It is a big issue to figure out the bioactive conformation in deep learning without the co-crystal structure or highly precise molecular simulations. In this study, we developed a deep learning framework of Multi-Conformation Point Network (MCPNET) to construct classification and regression models, respectively, based on electrostatic potential distributions on vdW surfaces around multiple conformations of the compound using a dataset of compounds with developmental toxicity in zebrafish embryo. MCPNET applied 3D multi-conformational surface point cloud to extract the molecular features for model training, which may be critical for capturing the structural diversity of compounds. The models achieved an accuracy of 85 % on the classification task and R2 of 0.66 on the regression task, outperforming traditional machine learning models and other deep learning models. The key feature of our model is its interpretability with the component visualization to identify the factors contributing to the prediction and to understand the compound action mechanism. MCPNET may predict the conformation quietly close to the bioactive conformation of a compound by attention-based multi-conformation pooling mechanism. Our results demonstrated the potential of deep learning based on 3D molecular representations in accurately predicting developmental toxicity. The source code is publicly available at https://github.com/Superlit-CC/MCPNET.


Assuntos
Aprendizado Profundo , Animais , Peixe-Zebra , Aprendizado de Máquina , Conformação Molecular , Software
10.
Biotechnol J ; 19(2): e2300437, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38403464

RESUMO

Psoriasis is a common immune-mediated skin condition characterized by aberrant keratinocytes and cell proliferation. The purpose of this study was to explore the FDA-approved drugs by 3D-QSAR pharmacophore model and evaluate their efficiency by in-silico, in vitro, and in vivo psoriasis animal model. A 3D-QSAR pharmacophore model was developed by utilizing HypoGen algorithm using the structural features of 48 diaryl derivatives with diverse molecular patterns. The model was validated by a test set of 27 compounds, by cost analysis method, and Fischer's randomization test. The correlation coefficient of the best model (Hypo2) was 0.9601 for the training set while it was 0.805 for the test set. The selected model was taken as a 3D query for the virtual screening of over 3000 FDA-approved drugs. Compounds mapped with the pharmacophore model were further screened through molecular docking. The hits that showed the best docking results were screened through in silico skin toxicity approach. Top five hits were selected for the MD simulation studies. Based on MD simulations results, the best two hit molecules, that is, ebastine (Ebs) and mebeverine (Mbv) were selected for in vitro and in vivo antioxidant studies performed in mice. TNF-α and COX pro-inflammatory mediators, biochemical assays, histopathological analyses, and immunohistochemistry observations confirmed the anti-inflammatory response of the selected drugs. Based on these findings, it appeared that Ebs can effectively treat psoriasis-like skin lesions and down-regulate inflammatory responses which was consistent with docking predictions and could potentially be employed for further research on inflammation-related skin illnesses such as psoriasis.


Assuntos
Farmacóforo , Psoríase , Animais , Camundongos , Simulação de Acoplamento Molecular , Relação Quantitativa Estrutura-Atividade , Simulação por Computador , Psoríase/tratamento farmacológico , Simulação de Dinâmica Molecular
11.
Mini Rev Med Chem ; 24(14): 1323-1333, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38265367

RESUMO

Rational predictions on binding kinetics parameters of drugs to targets play significant roles in future drug designs. Full conformational samplings of targets are requisite for accurate predictions of binding kinetic parameters. In this review, we mainly focus on the applications of enhanced sampling technologies in calculations of binding kinetics parameters and residence time of drugs. The methods involved in molecular dynamics simulations are applied to not only probe conformational changes of targets but also reveal calculations of residence time that is significant for drug efficiency. For this review, special attention are paid to accelerated molecular dynamics (aMD) and Gaussian aMD (GaMD) simulations that have been adopted to predict the association or disassociation rate constant. We also expect that this review can provide useful information for future drug design.


Assuntos
Simulação de Dinâmica Molecular , Cinética , Humanos , Ligação Proteica , Desenho de Fármacos , Preparações Farmacêuticas/química , Preparações Farmacêuticas/metabolismo
12.
Artigo em Inglês | MEDLINE | ID: mdl-38206777

RESUMO

Ultrasound imaging offers a noninvasive, radiation-free method for visualizing internal tissues and organs, with deep penetration capabilities. This has established it as a crucial tool for physicians in diagnosing internal tissue pathologies and monitoring human conditions. Nonetheless, conventional ultrasound probes are often characterized by their rigidity and bulkiness. Designing a transducer that can seamlessly adapt to the contours and dynamics of soft, curved human skin presents significant technical hurdles. We present a novel flexible and stretchable ultrasound transducer (FSUT) designed for adaptability to large-curvature surfaces while preserving superior imaging quality. Central to this breakthrough is the innovative use of screen-printed silver nanowires (AgNWs) coupled with a composite elastic substrate, together ensuring robust and stable electrical and mechanical connections. Standard tensile and fatigue tests verify its durability. The mechanical, electrical, and acoustic properties of FSUTs are characterized using standard methods, with large tensile strains (≥110%), high flexibility ( R ≥ 1.4 mm), and lightweight ( ≤ 1.58 g) to meet the needs of wearable devices. Center frequency and -6-dB bandwidth are approximately 5.3 MHz and 66.47%, respectively. Images of the commercial anechoic cyst phantom yielded an axial and lateral resolution (depths of 10-70 mm) of approximately 0.31 and 0.46, and 0.34 and 0.84 mm, respectively. The complex curved surface imaging capabilities of FSUT were tested on agar-gelatin-based breast cyst phantoms under different curvatures. Finally, ultrasound images of the thyroid, brachial, and carotid arteries were also obtained from volunteer wearing FSUT.


Assuntos
Desenho de Equipamento , Imagens de Fantasmas , Transdutores , Ultrassonografia , Dispositivos Eletrônicos Vestíveis , Humanos , Ultrassonografia/métodos , Ultrassonografia/instrumentação , Pele/diagnóstico por imagem , Nanofios/química
13.
Exp Eye Res ; 240: 109807, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38278468

RESUMO

Subretinal fluid (SRF) accumulates between photoreceptor outer segments and retinal pigment epithelium during rhegmatogenous retinal detachment. Biomolecular components such as lipids originate from cells surrounding the SRF. Knowledge of the composition of these molecules in SRF potentially provides mechanistic insight into the physiologic transfer of lipids between retinal tissue compartments. Using mass spectrometry and tandem mass spectrometry analysis on an electrospray ionization quadrupole-time-of-flight mass spectrometer, we identified a total of 115 lipid molecular species of 11 subclasses and 9 classes in two samples from two patients with rhegmatogenous retinal detachment. These included 47 glycerophosphocholines, 6 glycerophosphoethanolamines, 1 glycerophosphoinositol, 18 sphingomyelins, 9 cholesteryl esters, free cholesterol, 3 ceramides, 22 triacylglycerols and 8 free fatty acids. Glycerophosphocholines were of the highest intensity. By minimizing the formation of different adduct forms or clustering ions of different adducts, we determined the relative intensity of lipid molecular species within the same subclasses. The profiles were compared with those of retinal cells available in the published literature. The glycerophosphocholine profile of SRF was similar to that of cone outer segments, suggesting that outer segment degradation products are constitutively released into the interphotoreceptor matrix, appearing in SRF during detachment. This hypothesis was supported by the retinal distributions of corresponding lipid synthases' mRNA expression obtained from an online resource based on publicly available single-cell sequencing data. In contrast, based on lipid profiles and relevant gene expression in this study, the sources of free cholesterol and cholesteryl esters in SRF appeared more ambiguous, possibly reflecting that outer retina takes up plasma lipoproteins. Further studies to identify and quantify lipids in SRF will help better understand etiology of diseases relevant to outer retina.


Assuntos
Descolamento Retiniano , Humanos , Descolamento Retiniano/metabolismo , Líquido Sub-Retiniano/metabolismo , Ésteres do Colesterol/metabolismo , Lipidômica , Retina/metabolismo
14.
J Biomol Struct Dyn ; 42(7): 3363-3381, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-37216340

RESUMO

Point mutations play a vital role in the conformational transformation of HRAS. In this work, Gaussian accelerated molecular dynamics (GaMD) simulations followed by constructions of free energy landscapes (FELs) were adopted to explore the effect of mutations D33K, A59T and L120A on conformation states of the GDP-bound HRAS. The results from the post-processing analyses on GaMD trajectories suggest that mutations alter the flexibility and motion modes of the switch domains from HRAS. The analyses from FELs show that mutations induce more disordered states of the switch domains and affect interactions of GDP with HRAS, implying that mutations yield a vital effect on the binding of HRAS to effectors. The GDP-residue interaction network revealed by our current work indicates that salt bridges and hydrogen bonding interactions (HBIs) play key roles in the binding of GDP to HRAS. Furthermore, instability in the interactions of magnesium ions and GDP with the switch SI leads to the extreme disorder of the switch domains. This study is expected to provide the energetic basis and molecular mechanism for further understanding the function of HRAS.Communicated by Ramaswamy H. Sarma.


Assuntos
Simulação de Dinâmica Molecular , Mutação Puntual , Entropia , Mutação
15.
bioRxiv ; 2023 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-38106085

RESUMO

Resting-state functional connectivity (RSFC) is widely used to predict phenotypic traits in individuals. Large sample sizes can significantly improve prediction accuracies. However, for studies of certain clinical populations or focused neuroscience inquiries, small-scale datasets often remain a necessity. We have previously proposed a "meta-matching" approach to translate prediction models from large datasets to predict new phenotypes in small datasets. We demonstrated large improvement of meta-matching over classical kernel ridge regression (KRR) when translating models from a single source dataset (UK Biobank) to the Human Connectome Project Young Adults (HCP-YA) dataset. In the current study, we propose two meta-matching variants ("meta-matching with dataset stacking" and "multilayer meta-matching") to translate models from multiple source datasets across disparate sample sizes to predict new phenotypes in small target datasets. We evaluate both approaches by translating models trained from five source datasets (with sample sizes ranging from 862 participants to 36,834 participants) to predict phenotypes in the HCP-YA and HCP-Aging datasets. We find that multilayer meta-matching modestly outperforms meta-matching with dataset stacking. Both meta-matching variants perform better than the original "meta-matching with stacking" approach trained only on the UK Biobank. All meta-matching variants outperform classical KRR and transfer learning by a large margin. In fact, KRR is better than classical transfer learning when less than 50 participants are available for finetuning, suggesting the difficulty of classical transfer learning in the very small sample regime. The multilayer meta-matching model is publicly available at GITHUB_LINK.

16.
J Biomol Struct Dyn ; : 1-20, 2023 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-38112295

RESUMO

Cyclin dependent kinases (CDKs) play an important role in cell cycle regulation and their dysfunction is associated with many cancers. That is why CDKs have been attractive targets for the treatment of cancer. Glioblastoma is a cancer caused by the aberrant expression of CDK4/6, so exploring the mechanism of the selection of CDK4/6 toward inhibitors relative to the other family members CDK1/2 is essential. In this work, multiple replica molecular dynamics (MRMD) simulations, principal component analysis (PCA), free energy landscapes (FELs), molecular mechanics Poisson-Boltzmann/Generalized Born surface area (MM-PB/GBSA) and other methods were integrated to decipher the selectively binding mechanism of the inhibitor N1J to CDK4/6 and CDK1/2. Molecular electrostatic potential (MESP) analysis provides an explanation for the N1J selectivity. Residue-based free energy decomposition reveals that most of the hot residues are located at the same location of CDKs proteins, but the different types of residues in different proteins cause changes in binding energy, which is considered as a potential developmental direction to improve the selectivity of inhibitors to CDK4/6. These results provide insights into the source of inhibitor and CDK4/6 selectivity for the future development of more selective inhibitors.Communicated by Ramaswamy H. Sarma.

17.
Materials (Basel) ; 16(20)2023 Oct 19.
Artigo em Inglês | MEDLINE | ID: mdl-37895753

RESUMO

The disposal of glass fiber-reinforced plastic (GFRP) waste has become an urgent issue in both the engineering and environmental fields. In this study, the feasibility of reusing mechanically recycled GFRP in concrete was evaluated. Secondary screening of the recycled material was conducted to obtain different types of products, and the recycled GFRP (rGFRP) was characterized. Subsequently, the effect of rGFRP on concrete performance was evaluated using different dosages (0%, 1%, 3%, 5%) of rGFRP powder and rGFRP cluster (with different sizes and fiber contents) to replace fine aggregate in concrete preparation. The experimental results indicated that the addition of rGFRP powder has no significant impact on the mechanical properties of concrete, while the addition of a small amount of rGFRP cluster slightly improves the compressive strength and splitting tensile strength of concrete. Additionally, the short fibers in rGFRP improve the failure mode of concrete, and increased fiber content and longer fiber length demonstrate a more pronounced reinforcing effect. The challenges and potential directions for future research in the realm of reusing rGFRP in concrete are discussed at the end. A systematic process for reusing GFRP waste in concrete is proposed to address the primary challenges and provide guidance for its practical engineering application.

18.
Phys Chem Chem Phys ; 25(41): 28479-28496, 2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37846774

RESUMO

The COVID-19 pandemic caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) continues to spread globally, and rapid viral evolution and the emergence of new variants pose challenges to pandemic control. During infection, the spike protein of SARS-CoV-2 interacts with the human ACE2 protein via its receptor binding domain (RBD), and it is known that engineered forms of ACE2 can compete with wild-type (WT) ACE2 for binding to inhibit infection. Here, we conducted multiple replica molecular dynamics (MRMD) simulations to study the mechanisms of the engineered ACE2 variants 3N39 and 3N94 and provide directions for optimization. Our findings reveal that engineered ACE2 is notably more efficacious in systems that show weaker binding to WT ACE2 (i.e., WT and BA.1 RBD), but also faces immune escape as the virus evolves. Moreover, by modifying residue types near the binding interface, engineered ACE2 alters the electrostatic potential distribution and reconfigures the hydrogen bonding network, which results in modified binding to the RBD. However, this structural rearrangement does not occur in all RBD variants. In addition, we identified potentially engineerable beneficial residues and potentially engineerable detrimental residues in both ACE2 and RBD. Functional conservation can thus enable the optimization of these residues and improve the binding competitiveness of engineered ACE2, which therefore provides additional immune escape prevention. Finally, we conclude that these findings have implications for understanding the mechanisms responsible for engineered ACE2 and can help us to develop engineered ACE2 proteins that show superior performance.


Assuntos
Enzima de Conversão de Angiotensina 2 , Simulação de Dinâmica Molecular , Humanos , Sítios de Ligação , Ligação Competitiva , Pandemias , SARS-CoV-2/genética , Ligação Proteica , Mutação
19.
J Biomol Struct Dyn ; : 1-18, 2023 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-37740650

RESUMO

The pseudokinase domain (JH2) of the protein tyrosine kinase (Janus kinase 2, JAK2) regulates the activity of a tyrosine kinase domain (JH1) in JAK2, which is further affected by mutations in the JH2. In this work, Gaussian accelerated molecular dynamics (GaMD) simulations followed by construction of free energy landscapes (FELs) and principal component analysis (PCA) were performed to study effect of two mutations V617F and V617F/E596A on the conformations of the ATP-bound JH2. The dynamic analyses reveal that mutations affect the structural flexibility and correlated motions of the JH2, meanwhile also change the dynamics behavior of the P-loop and αC-helix of the JH2. The information from FELs unveils that mutations induce less energy states than the free JH2 and the WT one. The analyses of interaction networks uncover that mutations affect the salt bridge interactions of ATP with K581, K677 and R715 and alter hydrogen bonding interactions (HBIs) of ATP with the JH2. The changes in conformations of the JH2 and ATP-JH2 interaction networks caused by mutations in turn generate effect on the activity regulations of the JH2 on the JH1. This work is expected to provide significant theoretical helps for deeply understanding the function of the JH2 and drug design toward JAK2.Communicated by Ramaswamy H. Sarma.

20.
Accid Anal Prev ; 192: 107237, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37544041

RESUMO

The service states of tunnel lighting will directly affect the lighting conditions, which affect traffic safety. Therefore, it is imperative to evaluate and predict traffic safety accurately in different lighting states. In this research, three hundred experimental scenarios of the service states of tunnel lighting were designed and implemented to evaluate the impact of different service states of tunnel lighting on traffic safety. The evaluation was achieved through a visual identification experiment in a physical tunnel. The experimental results show higher simulated vehicle speeds pose a greater threat to traffic safety. The severity of lighting attenuation contributes to an increased risk to traffic safety. An increase in the number of luminaires failure also poses a greater threat to traffic safety. The newly proposed traffic safety factor was employed to evaluate traffic safety quantitatively in road tunnels. To improve the accuracy and comprehensiveness of the traffic safety factor prediction in different lighting service states, an advanced neural network prediction system was developed. The prediction system was constructed using the Sparrow Search Algorithm (SSA) to optimize Extreme Learning Machine (ELM) neural network, and the dataset from the experiment was used for the prediction model. The SSA-ELM neural network model is a reliable model that can predict the traffic safety factor comprehensively and accurately. The recommended threshold value for the traffic safety factor is 0.6. When the value falls below 0.6, it shows that the service states of tunnel lighting pose a threat to traffic safety in the tunnel. These findings can provide insights into the safe and energy-efficient maintenance of road tunnels.


Assuntos
Acidentes de Trânsito , Iluminação , Humanos , Acidentes de Trânsito/prevenção & controle , Segurança , Algoritmos , Redes Neurais de Computação
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