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1.
EMBO J ; 40(13): e106272, 2021 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-33942347

RESUMO

Cellular stress has been associated with inflammation, yet precise underlying mechanisms remain elusive. In this study, various unrelated stress inducers were employed to screen for sensors linking altered cellular homeostasis and inflammation. We identified the intracellular pattern recognition receptors NOD1/2, which sense bacterial peptidoglycans, as general stress sensors detecting perturbations of cellular homeostasis. NOD1/2 activation upon such perturbations required generation of the endogenous metabolite sphingosine-1-phosphate (S1P). Unlike peptidoglycan sensing via the leucine-rich repeats domain, cytosolic S1P directly bound to the nucleotide binding domains of NOD1/2, triggering NF-κB activation and inflammatory responses. In sum, we unveiled a hitherto unknown role of NOD1/2 in surveillance of cellular homeostasis through sensing of the cytosolic metabolite S1P. We propose S1P, an endogenous metabolite, as a novel NOD1/2 activator and NOD1/2 as molecular hubs integrating bacterial and metabolic cues.


Assuntos
Inflamação/metabolismo , Lisofosfolipídeos/metabolismo , Proteína Adaptadora de Sinalização NOD1/metabolismo , Proteína Adaptadora de Sinalização NOD2/metabolismo , Esfingosina/análogos & derivados , Animais , Linhagem Celular , Linhagem Celular Tumoral , Feminino , Células HEK293 , Células HeLa , Humanos , Camundongos , NF-kappa B/metabolismo , Peptidoglicano/metabolismo , Transdução de Sinais/fisiologia , Esfingosina/metabolismo , Células THP-1
2.
J Chem Inf Model ; 63(12): 3854-3864, 2023 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-37307245

RESUMO

Structural dynamics and conformational transitions are crucial for the activities of enzymes. As one of the most widely used industrial biocatalysts, lipase could be activated by the water-oil interfaces. The interface activations were believed to be dominated by the close-to-open transitions of the lid subdomains. However, the detailed mechanism and the roles of structure transitions are still under debate. In this study, the dynamic structures and conformational transitions of Burkholderia cepacia lipase (LipA) were investigated by combining all-atom molecular dynamics simulations, enhanced sampling simulation, and spectrophotometric assay experiments. The conformational transitions between the lid-open and lid-closed states of LipA in aqueous solution are directly observed by the computational simulation methods. The interactions between the hydrophobic residues on the two lid-subdomains are the driven forces for the LipA closing. Meanwhile, the hydrophobic environment provided by the oil interfaces would separate the interactions between the lid-subdomains and promote the structure opening of LipA. Moreover, our studies demonstrate the opening of the lids structure is insufficient to initiate the interfacial activation, providing explanations for the inability of interfacial activation of many lipases with lid structures.


Assuntos
Burkholderia cepacia , Água , Água/química , Lipase/química , Burkholderia cepacia/metabolismo , Simulação de Dinâmica Molecular , Conformação Proteica
3.
J Chem Inf Model ; 63(13): 4147-4157, 2023 07 10.
Artigo em Inglês | MEDLINE | ID: mdl-37357790

RESUMO

The tyrosine-protein kinase Met (c-Met) is an important signaling molecule involved in cellular growth and division. The dysregulation of c-Met may induce many fatal diseases, including non-small cell lung cancer, gastrointestinal cancers, hepatocellular carcinoma, etc. The activation of the c-Met kinase is dominant by the structure and dynamics of many important functional motifs, which are regulated by adenosine triphosphate (ATP) binding. c-Met inhibitors bind to the ATP-binding site or the allosteric pocket to compete with ATP molecules or alter the conformation of the function-related domains. Nevertheless, the mechanisms of ligand binding to c-Met are still unclear, especially the regulation of the functional motifs by different inhibitors. These greatly impede the development of novel drugs to overcome the drug tolerance to the currently marketed c-Met inhibitors. In this study, we used enhanced sampling technology to study the binding and regulation of two specific c-Met inhibitors. The results show that the two ligands adopt different binding processes even though with similar binding affinity. More importantly, our results uncovered different protein conformational features and the correlated motions of functional motifs regulated by the inhibitors, providing the structural basis for the functional suppression of the protein kinases.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Humanos , Ligantes , Sítios de Ligação , Trifosfato de Adenosina/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Inibidores de Proteínas Quinases/química , Ligação Proteica , Regulação Alostérica
4.
J Chem Inf Model ; 63(16): 5232-5243, 2023 08 28.
Artigo em Inglês | MEDLINE | ID: mdl-37574904

RESUMO

Fatty acids (FAs) are one of the essential energy sources for physiological processes, and they play a vital role in regulating immune and inflammatory responses, promoting cell differentiation and apoptosis, and inhibiting tumor growth. These functions are carried out by FA binding proteins (FABPs) that recognize and transport FAs. Although the crystal structure of the FA-FABPs complex has long been characterized, the mechanism behind FA binding and dissociation from FABP remains unclear. This study employed conventional MD simulations and enhanced sampling technologies to investigate the atomic-scale complexes of heart fatty acid binding proteins and stearic acid (SA). The results revealed two primary pathways for the binding or dissociation of the flexible long-chain ligand, with the orientation of the SA carboxyl head during dissociation determining the chosen path. Conformational changes in the portal region of FABP during the ligand binding/unbinding were found to be trivial, and the overturn of the ″cap″ or the unfolding of the α2 helix was not required. This study resolves the long-standing debate on the binding mechanism of SA with the long-flexible tail to FABP, which significantly improves the understanding of the transport mechanism of FABPs and the development of related therapeutic agents.


Assuntos
Proteínas de Ligação a Ácido Graxo , Proteínas de Neoplasias , Proteínas de Ligação a Ácido Graxo/química , Ligantes , Proteínas de Neoplasias/metabolismo , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Ligação Proteica
5.
J Chem Inf Model ; 62(15): 3651-3663, 2022 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-35848778

RESUMO

Protein kinases intrinsically translate their conformations between active and inactive states, which is key to their enzymatic activities. The conformational flipping of the three-residue conservative motif, Asp-Phe-Gly (DFG), is crucial for many kinases' biological functions. Obtaining a detailed demonstration of the DFG flipping process and its corresponding dynamical and thermodynamical features could broaden our understanding of kinases' conformation-activity relationship. In this study, we employed metadynamics simulation, a widely used enhanced sampling technique, to analyze the conformational transition pathways of the DFG flipping for the c-Met kinase. The corresponding free energy landscape suggested two distinct transition pathways between the "DFG-in" and "DFG-out" states of the DFG-flip from c-Met. On the basis of the orientation direction of the F1223 residue, we correspondingly named the two pathways the "DFG-up" path, featuring forming a commonly discovered "DFG-up" transition state, and the "DFG-down" path, a unique transition pathway with F1223 rotating along the opposite direction away from the hydrophobic cavity. The free energies along the two pathways were then calculated using the Path Collective Variable (PCV) metadynamics simulation. The simulation results showed that, though having similar free energy barriers, the free energy cuve for the DFG-down path suggested a two-step conformational transition mechanism, while that for the DFG-up path showed the one-step transition feature. The c-Met DFG flipping mechanism and the new intermediate state discovered in this work could provide a deeper understanding of the conformation-activity relationship for c-Met and, possibly, reveal a new conformational state as the drug target for c-Met and other similar kinases.


Assuntos
Simulação de Dinâmica Molecular , Proteínas Quinases , Simulação por Computador , Interações Hidrofóbicas e Hidrofílicas , Conformação Molecular , Conformação Proteica
6.
J Chem Inf Model ; 62(21): 5267-5275, 2022 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-35040651

RESUMO

The dimerization of transactive response DNA-binding protein of 43 kDa (TDP-43) is crucial for the RNA metabolism, and the higher-order aggregation of TDP-43 would induce several neurodegenerative diseases. The dimerization and aggregation of TDP-43 are regulated by the phosphorylation on its N-terminal domain (NTD). Understanding the regulation mechanism of TDP-43 NTD dimerization is crucial for the preventing of harmful aggregation and the associated diseases. In this study, the dimerization processes of wild-type (WT), phosphorylated S48 (pS48), and phosphomimic S48E mutation (S48E) of TDP-43 NTD are characterized by the enhanced sampling technology. Our results show that the phosphorylation not only shift the conformation population of bound and unbound state of TDP-43 NTD, but also would regulate the dimerization processes, including increase the binding free-energy barrier. The phosphomimic mutation would also shift the conformational space of TDP-43 NTD dimer to the unbound structures; however, the thermodynamic and kinetic properties of the dimerization processes between the phosphorylated and phosphomimic mutant systems are distinct, which reminds us to carefully study the phosphorylation regulation by using the phosphomimic mutations.


Assuntos
Proteínas de Ligação a DNA , Fosforilação , Proteínas de Ligação a DNA/química , Termodinâmica , Dimerização , Mutação
7.
J Chem Inf Model ; 62(21): 5233-5245, 2022 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-34506144

RESUMO

As a major drug target for anti-inflammatory therapy, the glucocorticoid receptor (GR) regulates a wide range of physiological processes through transactivation (TA) or transrepression. GR TA is involved in many adverse effects of GR-targeting drugs, and therefore, the discovery of novel GR ligands with lower TA activity and longer residence time is quite urgent. Undoubtedly, understanding the ligand dissociation mechanisms and the structural basis of the TA regulation is crucial for the development of novel GR-targeting drugs. Here, we used random accelerated molecular dynamics (RAMD) and funnel metadynamics (FM) simulations to explore the dissociation mechanisms of 5 classic glucocorticoids and 6 nonsteroidal GR ligands. Multiple ligand dissociation pathways were discovered. The classic glucocorticoids exhibit a strong preference for Path I, and most nonsteroidal ligands tend to dissociate along mixed pathways. We also find that the distinct unbinding preferences for AZD2906 and AZD9567, two representative nonsteroidal ligands with similar scaffolds but different TA activities, are primarily determined by their different polar interactions with the surrounding residues. Notably, the binding of AZD9567 poses a substantial impact on the conformation of the GR homodimer interface, which provides a valuable clue to understand the mechanisms of the TA-related side effects induced by the adjustments of the homodimerization process. These findings are critical for the structure-based rational design of novel GR ligands with more potent anti-inflammatory potency and reduced side effects.


Assuntos
Glucocorticoides , Receptores de Glucocorticoides , Receptores de Glucocorticoides/química , Ligantes , Ativação Transcricional , Glucocorticoides/farmacologia , Anti-Inflamatórios/farmacologia
8.
Angew Chem Int Ed Engl ; 60(33): 18280-18288, 2021 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-34081387

RESUMO

To overcome a series of challenges in tumor therapy, modular-agent probes (MAPs) comprised of various functional modules have been proposed. Researchers have tried to optimize the MAPs by exploiting the new modules or increasing the numbers of module, while neglecting the configuration of various modules. Here, we focus on the different spatial arrangements of existing modules. By utilizing a tetraphenylethylene (TPE) derivative with stereochemical structure and dual modifiable end-group sites as small molecule scaffold, two MAPs with same modular agents (module T for enhancing the internalization of MAPs by tumor cells and module M for causing mitochondrial dysfunction) but different spatial arrangements (on the one side, TM-AIE, and two sides, T-AIE-M, of the molecule scaffold) are designed. T-AIE-M with larger RGD binding angle performed higher specificity, while TM-AIE characterizing longer α-helix structure displayed superior toxicity.


Assuntos
Corantes Fluorescentes/química , Imagem Óptica , Estilbenos/química , Células HeLa , Humanos , Estrutura Molecular
9.
Proteins ; 88(11): 1401-1412, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32519403

RESUMO

Mixed lineage leukemia protein (MLL1 protein) recognizes the CpG site via its CXXC domain and is frequently associated with leukemia. The specific recognition is abolished by C1188D mutation, which also prevents MLL-related leukemia. In this paper, multiple molecular dynamic (MD) simulations were performed to investigate the mechanism of recognition and influences of C1188D mutation. Started from fully dissociated DNA and MLL1-CXXC domain, remarkably, the center of mass (COM) of MLL1-CXXC domain quickly concentrates on the vicinity of the CpG site in all 53 short MD simulations. Extended simulations of the wild type showed that the native complex formed in 500 ns among 4 of 53 simulations. In contrast, the C1188D mutant COM distributed broadly around the DNA and the native complex was not observed in any of the extended simulations. Simulations on the apo MLL1-CXXC domain further suggest that the wild type protein remained predominantly in an open form that closely resembles its structure in the native complex whereas C1188D mutant formed predominantly compact structures in which the N- terminal bends to D1188. This conformational switch hinders the formation of encounter complex, thus abolishes the recognition. Our study also provides clues to the study mechanism of recognition, by the CXXC domain from proteins like DNA methyltransferase and ten-eleven translocation enzymes.


Assuntos
Ácido Aspártico/química , Cisteína/química , DNA/química , Histona-Lisina N-Metiltransferase/química , Mutação , Proteína de Leucina Linfoide-Mieloide/química , Substituição de Aminoácidos , Ácido Aspártico/metabolismo , Sítios de Ligação , Ilhas de CpG , Cisteína/metabolismo , DNA/genética , DNA/metabolismo , Histona-Lisina N-Metiltransferase/genética , Histona-Lisina N-Metiltransferase/metabolismo , Humanos , Simulação de Dinâmica Molecular , Proteína de Leucina Linfoide-Mieloide/genética , Proteína de Leucina Linfoide-Mieloide/metabolismo , Conformação de Ácido Nucleico , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Eletricidade Estática , Termodinâmica
10.
Phys Chem Chem Phys ; 22(5): 2938-2948, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31951234

RESUMO

Eukaryotic translation initiation factor 4E binding protein 2 (4E-BP2) is an inhibitor of mRNA cap-dependent translations. Wild-type (WT) 4E-BP2 is intrinsically disordered under physiological conditions, while phosphorylation converts the disordered fragments 18-62 into a four-stranded ß-sheet structure. The regulation mechanism of phosphorylation on 4E-BP2 still remains ambiguous. In this study, replica-exchange molecular dynamics (REMD) simulations were utilized to sample the conformation spaces of WT, phosphorylated WT (pWT), and phosphorylated mutated (pMT) 4E-BP2. Starting from extended structures, the folded structures were only observed in pWT simulations. The folding pathway shows that the folded structures of pWT are formed in the order of ß1/ß4, ß3, and ß2. The formation of ß-turns on pWT, which are driven by hydrogen bonds between the phosphorylated residues and adjacent residues, are the rate-limiting steps in the folding process. The long-range electrostatic interactions contribute toward the stabilization of the folded structures. Moreover, the disruption of ß-turn structures induced by mutations would prevent the folding of pMT 4E-BP2. Our finding is helpful in understanding the regulation of the structural ensembles of intrinsically disordered proteins.


Assuntos
Fatores de Iniciação em Eucariotos/metabolismo , Proteínas Intrinsicamente Desordenadas/metabolismo , Sequência de Aminoácidos , Fatores de Iniciação em Eucariotos/química , Fatores de Iniciação em Eucariotos/genética , Humanos , Ligação de Hidrogênio , Proteínas Intrinsicamente Desordenadas/química , Proteínas Intrinsicamente Desordenadas/genética , Simulação de Dinâmica Molecular , Mutagênese Sítio-Dirigida , Fosforilação , Conformação Proteica em Folha beta , Dobramento de Proteína , Termodinâmica
11.
Proteins ; 87(7): 541-550, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-30803034

RESUMO

Exploring the accurate structure ensembles are critical to understand the functions of intrinsically disordered proteins (IDPs). As a well-known IDP, islet amyloid polypeptide (IAPP) plays important roles in the development of human type II diabetes (T2D). The toxicity of human IAPP (hIAPP) is induced by the amyloidosis of the peptide, however, its aggregation mechanism remains ambiguous. The characterization of structure ensemble of hIAPP, as well as the differences between hIAPP and its non-amyloidogenic homologous such as rat IAPP (rIAPP), would greatly help to illuminate the amyloidosis mechanism of IAPP. In this study, the atomic structure ensembles of hIAPP and rIAPP were characterized by all-atom molecular dynamics (MD) simulations combined with enhanced sampling technology and experiment data restraints. The obtained structure ensembles were firstly compared with those determined by the conventional MD (cMD) and enhanced sampling without experiment data restraints. The results showed that the enhanced sampling and experiment data restraints would improve the simulation accuracy. The transient N-terminal α-helix structures were adopted by the sub-states of both hIAPP and rIAPP, however, the C-terminal helical structures were only present on hIAPP. The hydrophobic residues in the amyloid-core region of hIAPP are exposed to the solvent. The structure ensemble differences between hIAPP and rIAPP revealed in this work provide potential explain to the amyloidogenic mechanism and would be helpful for the design of drugs to combat T2D.


Assuntos
Proteínas Intrinsicamente Desordenadas/química , Polipeptídeo Amiloide das Ilhotas Pancreáticas/química , Sequência de Aminoácidos , Animais , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Proteínas Intrinsicamente Desordenadas/metabolismo , Polipeptídeo Amiloide das Ilhotas Pancreáticas/metabolismo , Simulação de Dinâmica Molecular , Agregados Proteicos , Agregação Patológica de Proteínas/metabolismo , Conformação Proteica , Estrutura Secundária de Proteína , Ratos
12.
J Chem Inf Model ; 59(2): 842-857, 2019 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-30658039

RESUMO

Androgen receptor (AR), as a member of the nuclear receptor (NR) superfamily, regulates the gene transcription in response to the sequential binding of diverse agonists and coactivators. Great progress has been made in studies on the pharmacology and structure of AR, but the atomic level mechanism of the bidirectional communications between the ligand-binding pocket (LBP) and the activation function-2 (AF2) region of AR remains poorly understood. Therefore, in this study, molecular dynamics (MD) simulations and free energy calculations were carried out to explore the interactions among water, agonist (DHT) or antagonist (HFT), AR, and coactivator (SRC3). Upon the binding of an agonist (DHT) or antagonist (HFT), the LBP structure would transform to the agonistic or antagonistic state, and the conformational changes of the LBP would regulate the structure of the AF2 surface. As a result, the binding of the androgen DHT could promote the recruitment of the coactivator SRC3 to the AF2, and on the contrary, the binding of the antagonist HFT would induce a perturbation to the shape of the AF2 and then weaken its accommodating capability of the coactivators with the LXXLL motif. The simulation results illustrated that the DHT-AR binding affinity was enhanced by the association of the coactivator SRC3, which would reduce the conformational fluctuation of the AR-LBD and expand the size of the AR LBP. On the other hand, the coactivator-to-HFT allosteric pathway, which involves the SRC3, helix 3 (H3), helix 4 (H4), the loop (L1-3) between helix 1 (H1) and H3, and HFT, was characterized. The HFT's skewness and different interactions between HFT and the LBP were observed in the SRC3-present AR. The mutual communications between the AF2 surface and LBP, together with the processes involving the interplay of the ligand binding and coactivator recruitment events, would help in understanding the association of coactivators and rationally develop potent drugs to inhibit the activity of AR.


Assuntos
Simulação de Dinâmica Molecular , Receptores Androgênicos/química , Receptores Androgênicos/metabolismo , Motivos de Aminoácidos , Sequência de Aminoácidos , Sítios de Ligação , Ligantes , Coativador 3 de Receptor Nuclear/metabolismo , Ligação Proteica , Termodinâmica
13.
J Chem Phys ; 151(10): 105101, 2019 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-31521094

RESUMO

The diffusion map is a dimensionality reduction method. The reduction coordinates are associated with the leading eigenfunctions of the backward Fokker-Planck operator, providing a dynamic meaning for these coordinates. One of the key factors that affect the accuracy of diffusion map embedding is the dynamic measure implemented in the Gaussian kernel. A common practice in diffusion map study of molecular systems is to approximate dynamic proximity with RMSD (root-mean-square deviation). In this paper, we present a hybrid geometry-energy based kernel. Since high energy-barriers may exist between geometrically similar conformations, taking both RMSD and energy difference into account in the kernel can better describe conformational transitions between neighboring conformations and lead to accurate embedding. We applied our diffusion map method to the ß-hairpin of the B1 domain of streptococcal protein G and to Trp-cage. Our results in ß-hairpin show that the diffusion map embedding achieves better results with the hybrid kernel than that with the RMSD-based kernel in terms of free energy landscape characterization and a new correlation measure between the cluster center Euclidean distances in the reduced-dimension space and the reciprocals of the total net flow between these clusters. In addition, our diffusion map analysis of the ultralong molecular dynamics trajectory of Trp-cage has provided a unified view of its folding mechanism. These promising results demonstrate the effectiveness of our diffusion map approach in the analysis of the dynamics and thermodynamics of molecular systems. The hybrid geometry-energy criterion could be also useful as a general dynamic measure for other purposes.


Assuntos
Proteínas de Bactérias/química , Peptídeos/química , Algoritmos , Difusão , Cadeias de Markov , Simulação de Dinâmica Molecular , Conformação Proteica em Folha beta , Domínios Proteicos , Termodinâmica
14.
Int J Mol Sci ; 20(14)2019 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-31311155

RESUMO

As a member of the fatty acids transporter family, the heart fatty acid binding proteins (HFABPs) are responsible for many important biological activities. The binding mechanism of fatty acid with FABP is critical to the understanding of FABP functions. The uncovering of binding-relevant intermediate states and interactions would greatly increase our knowledge of the binding process. In this work, all-atom molecular dynamics (MD) simulations were performed to characterize the structural properties of nativelike intermediate states. Based on multiple 6 µs MD simulations and Markov state model (MSM) analysis, several "open" intermediate states were observed. The transition rates between these states and the native closed state are in good agreement with the experimental measurements, which indicates that these intermediate states are binding relevant. As a common property in the open states, the partially unfolded α2 helix generates a larger portal and provides the driving force to facilitate ligand binding. On the other side, there are two kinds of open states for the ligand-binding HFABP: one has the partially unfolded α2 helix, and the other has the looser ß-barrel with disjointing ßD-ßE strands. Our results provide atomic-level descriptions of the binding-relevant intermediate states and could improve our understanding of the binding mechanism.


Assuntos
Proteínas de Ligação a Ácido Graxo/química , Simulação de Acoplamento Molecular , Sítios de Ligação , Proteínas de Ligação a Ácido Graxo/metabolismo , Ácidos Graxos/química , Ácidos Graxos/metabolismo , Humanos , Simulação de Dinâmica Molecular , Ligação Proteica
15.
J Chem Inf Model ; 58(8): 1652-1661, 2018 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-29993249

RESUMO

The androgen receptor (AR) plays important roles in gene expression regulation, sexual phenotype maintenance, and prostate cancer (PCa) development. The communications between the AR ligand-binding domain (LBD) and its coactivator are critical to the activation of AR. It is still unclear how the ligand binding would affect the AR-coactivator interactions. In this work, the effects of the ligand binding on the AR-coactivator communications were explored by molecular dynamics (MD) simulations. The results showed that the ligand binding regulates the residue interactions in the function site AF-2. The ligand-to-coactivator allosteric pathway, which involves the coactivator, helix 3 (H3), helix 4 (H4), the loop between H3 and H4 (L3), and helix 12 (H12), and ligands, was characterized. In addition, the interactions of residues on the function site BF-3, especially on the boundary of AF-2 and BF-3, are also affected by the ligands. The MM/GBSA free energy calculations demonstrated that the binding affinity between the coactivator and apo-AR is roughly weaker than those between the coactivator and antagonistic ARs but stronger than those between the coactivator and agonistic ARs. The results indicated that the long-range electrostatic interactions and the conformational entropies are the main factors affecting the binding free energies. In addition, the F876L mutation on AR-LBD affects the ligand-to-coactivator allosteric pathway, which could be the reason for point mutation induced tolerance for the antagonistic drugs such as enzalutamide. Our study would help to develop novel drug candidates against PCa.


Assuntos
Antagonistas de Receptores de Andrógenos/farmacologia , Androgênios/farmacologia , Receptores Androgênicos/metabolismo , Sítios de Ligação/efeitos dos fármacos , Humanos , Ligantes , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Ligação Proteica/efeitos dos fármacos , Conformação Proteica/efeitos dos fármacos , Receptores Androgênicos/química , Receptores Androgênicos/genética
16.
J Chem Phys ; 143(13): 135101, 2015 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-26450332

RESUMO

The folding kinetics of Rd-apocytochrome b562 is two-state, but native-state hydrogen exchange experiments show that there are discrete partially unfolded (PUF) structures in equilibrium with the native state. These PUF structures are called hidden intermediates because they are not detected in kinetic experiments and they exist after the rate-limiting step. Structures of the mimics of hidden intermediates of Rd-apocytochrome b562 are resolved by NMR. Based upon their relative stability and structural features, the folding mechanism was proposed to follow a specific pathway (unfolded → rate-limiting transition state → PUF1 → PUF2 → native). Investigating the roles of equilibrium PUF structures in folding kinetics and their interrelationship not only deepens our understanding of the details of folding mechanism but also provides guides in protein design and prevention of misfolding. We performed molecular dynamics simulations starting from a hidden intermediate and the native state of Rd-apocytochrome b562 in explicit solvent, for a total of 37.18 µs mainly with Anton. We validated our simulations by detailed comparison with experimental data and other computations. We have verified that we sampled the post rate-limiting transition state region only. Markov state model was used to analyze the simulation results. We replace the specific pathway model with a network model. Transition-path theory was employed to calculate the net effective flux from the most unfolded state towards the most folded state in the network. The proposed sequential folding pathway via PUF1 then more stable, more native-like PUF2 is one of the routes in our network, but it is not dominant. The dominant path visits PUF2 without going through PUF1. There is also a route from PUF1 directly to the most folded state in the network without visiting PUF2. Our results indicate that the PUF states are not necessarily sequential in the folding. The major routes predicted in our network are testable by future experiments such as single molecule experiment.


Assuntos
Citocromos b/química , Simulação de Dinâmica Molecular , Citocromos b/metabolismo , Cinética , Ressonância Magnética Nuclear Biomolecular , Conformação Proteica , Dobramento de Proteína
17.
Proteins ; 82(10): 2585-96, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-24913095

RESUMO

Dimensionality reduction is widely used in searching for the intrinsic reaction coordinates for protein conformational changes. We find the dimensionality-reduction methods using the pairwise root-mean-square deviation (RMSD) as the local distance metric face a challenge. We use Isomap as an example to illustrate the problem. We believe that there is an implied assumption for the dimensionality-reduction approaches that aim to preserve the geometric relations between the objects: both the original space and the reduced space have the same kind of geometry, such as Euclidean geometry vs. Euclidean geometry or spherical geometry vs. spherical geometry. When the protein free energy landscape is mapped onto a 2D plane or 3D space, the reduced space is Euclidean, thus the original space should also be Euclidean. For a protein with N atoms, its conformation space is a subset of the 3N-dimensional Euclidean space R(3N). We formally define the protein conformation space as the quotient space of R(3N) by the equivalence relation of rigid motions. Whether the quotient space is Euclidean or not depends on how it is parameterized. When the pairwise RMSD is employed as the local distance metric, implicit representations are used for the protein conformation space, leading to no direct correspondence to a Euclidean set. We have demonstrated that an explicit Euclidean-based representation of protein conformation space and the local distance metric associated to it improve the quality of dimensionality reduction in the tetra-peptide and ß-hairpin systems.


Assuntos
Proteínas de Bactérias/química , Modelos Moleculares , Oligopeptídeos/química , Fragmentos de Peptídeos/química , Transferência de Energia , Simulação de Dinâmica Molecular , Análise de Componente Principal , Conformação Proteica , Dobramento de Proteína , Domínios e Motivos de Interação entre Proteínas , Estrutura Secundária de Proteína , Desdobramento de Proteína , Estatística como Assunto , Propriedades de Superfície , Terminologia como Assunto
18.
JACS Au ; 4(4): 1422-1435, 2024 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-38665647

RESUMO

The essential forces stabilizing membrane proteins and governing their folding and unfolding are difficult to decipher. Single-molecule atomic force spectroscopy mechanically unfolds individual membrane proteins and quantifies their dynamics and energetics. However, it remains challenging to structurally assign unfolding intermediates precisely and to deduce dominant interactions between specific residues that facilitate either the localized stabilization of these intermediates or the global assembly of membrane proteins. Here, we performed force spectroscopy experiments and multiscale molecular dynamics simulations to study the unfolding pathway of diacylglycerol kinase (DGK), a small trimeric multispan transmembrane enzyme. The remarkable agreement between experiments and simulations allowed precise structural assignment and interaction analysis of unfolding intermediates, bypassing existing limitations on structural mapping, and thus provided mechanistic explanations for the formation of these states. DGK unfolding was found to proceed with structural segments varying in size that do not correlate with its secondary structure. We identified intermolecular side-chain packing interactions as one of the major contributions to the stability of unfolding intermediates. Mutagenesis creating packing defects induced a dramatic decrease in the mechano-stability of corresponding intermediates and also in the thermo-stability of DGK trimer, in good agreement with predictions from simulations. Hence, the molecular determinants of the mechano- and thermo-stability of a membrane protein can be identified at residue resolution. The accurate structural assignment established and microscopic mechanism revealed in this work may substantially expand the scope of single-molecule studies of membrane proteins.

19.
Sci Adv ; 10(19): eade9520, 2024 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-38718112

RESUMO

Fast collective motions are widely present in biomolecules, but their functional relevance remains unclear. Herein, we reveal that fast collective motions of backbone are critical to the water transfer of aquaporin Z (AqpZ) by using solid-state nuclear magnetic resonance (ssNMR) spectroscopy and molecular dynamics (MD) simulations. A total of 212 residue site-specific dipolar order parameters and 158 15N spin relaxation rates of the backbone are measured by combining the 13C- and 1H-detected multidimensional ssNMR spectra. Analysis of these experimental data by theoretic models suggests that the small-amplitude (~10°) collective motions of the transmembrane α helices on the nanosecond-to-microsecond timescales are dominant for the dynamics of AqpZ. The MD simulations demonstrate that these collective motions are critical to the water transfer efficiency of AqpZ by facilitating the opening of the channel and accelerating the water-residue hydrogen bonds renewing in the selectivity filter region.


Assuntos
Aquaporinas , Simulação de Dinâmica Molecular , Água , Água/química , Aquaporinas/química , Aquaporinas/metabolismo , Conformação Proteica em alfa-Hélice , Ligação de Hidrogênio , Espectroscopia de Ressonância Magnética , Ressonância Magnética Nuclear Biomolecular , Proteínas de Escherichia coli
20.
Adv Sci (Weinh) ; 11(19): e2309261, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38481034

RESUMO

Androgen receptor (AR) antagonists are widely used for the treatment of prostate cancer (PCa), but their therapeutic efficacy is usually compromised by the rapid emergence of drug resistance. However, the lack of the detailed interaction between AR and its antagonists poses a major obstacle to the design of novel AR antagonists. Here, funnel metadynamics is employed to elucidate the inherent regulation mechanisms of three AR antagonists (hydroxyflutamide, enzalutamide, and darolutamide) on AR. For the first time it is observed that the binding of antagonists significantly disturbed the C-terminus of AR helix-11, thereby disrupting the specific internal hydrophobic contacts of AR-LBD and correspondingly the communication between AR ligand binding pocket (AR-LBP), activation function 2 (AF2), and binding function 3 (BF3). The subsequent bioassays verified the necessity of the hydrophobic contacts for AR function. Furthermore, it is found that darolutamide, a newly approved AR antagonist capable of fighting almost all reported drug resistant AR mutants, can induce antagonistic binding structure. Subsequently, docking-based virtual screening toward the dominant binding conformation of AR for darolutamide is conducted, and three novel AR antagonists with favorable binding affinity and strong capability to combat drug resistance are identified by in vitro bioassays. This work provides a novel rational strategy for the development of anti-resistant AR antagonists.


Assuntos
Antagonistas de Receptores de Andrógenos , Benzamidas , Antagonistas de Receptores de Andrógenos/farmacologia , Antagonistas de Receptores de Andrógenos/química , Humanos , Benzamidas/farmacologia , Feniltioidantoína/farmacologia , Feniltioidantoína/análogos & derivados , Masculino , Receptores Androgênicos/metabolismo , Receptores Androgênicos/química , Receptores Androgênicos/genética , Nitrilas/farmacologia , Simulação de Dinâmica Molecular , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genética , Pirazóis/farmacologia , Pirazóis/química , Simulação de Acoplamento Molecular/métodos , Amidas/farmacologia , Amidas/química , Flutamida/análogos & derivados
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