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1.
Abstract

P21-activated kinase 4 (PAK4) is a serine/threonine protein kinase, which is associated with many cancer diseases, and thus being considered as a potential drug target. In this study, three-dimensional quantitative structure-activity relationship (3D-QSAR), molecular docking and molecular dynamics (MD) simulations were performed to explore the structure-activity relationship of a series of pyrropyrazole PAK4 inhibitors. The statistical parameters of comparative molecular field analysis (CoMFA, Q 2 = 0.837, R 2 = 0.990, and R 2 pred = 0.967) and comparative molecular similarity indices analysis (CoMSIA, Q 2 = 0.720, R 2 = 0.972, and R 2 pred = 0.946) were obtained from 3D-QSAR model, which exhibited good predictive ability and significant statistical reliability. The binding mode of PAK4 with its inhibitors was obtained through molecular docking study, which indicated that the residues of GLU396, LEU398, LYS350, and ASP458 were important for activity. Molecular mechanics generalized born surface area (MM-GBSA) method was performed to calculate the binding free energy, which indicated that the coulomb, lipophilic and van der Waals (vdW) interactions made major contributions to the binding affinity. Furthermore, through 100?ns MD simulations, we obtained the key amino acid residues and the types of interactions they participated in. Based on the constructed 3D-QSAR model, some novel pyrropyrazole derivatives targeting PAK4 were designed with improved predicted activities. Pharmacokinetic and toxicity predictions of the designed PAK4 inhibitors were obtained by the pkCSM, indicating these compounds had better absorption, distribution, metabolism, excretion and toxicity (ADMET) properties. Above research provided a valuable insight for developing novel and effective pyrropyrazole compounds targeting PAK4.  相似文献   

2.
Atom-based three dimensional-quantitative structure–activity relationship (3D-QSAR) model was developed on the basis of 5-point pharmacophore hypothesis (AARRR) with two hydrogen bond acceptors (A) and three aromatic rings for the derivatives of thieno[2,3-b]pyridine, which modulates the activity to inhibit the mGluR5 receptor. Generation of a highly predictive 3D-QSAR model was performed using the alignment of predicted pharmacophore hypothesis for the training set (R2?=?0.84, SD?=?0.26, F?=?45.8, N?=?29) and test set (Q2?=?0.74, RMSE?=?0.235, Pearson-R?=?0.94, N?=?9). The best pharmacophore hypothesis AARRR was selected, and developed three dimensional-quantitative structure activity relationship (3D-QSAR) model also supported the outcome of this study by means of favorable and unfavorable electron withdrawing group and hydrophobic regions of most active compound 42d and least active compound 18b. Following, induced fit docking and binding free energy calculations reveals the reliable binding orientation of the compounds. Finally, molecular dynamics simulations for 100?ns were performed to depict the protein–ligand stability. We anticipate that the resulted outcome could be supportive to discover potent negative allosteric modulators for metabotropic glutamate receptor 5 (mGluR5).  相似文献   

3.
Development of multi-target drugs is becoming increasingly attractive in the repertoire of protein kinase inhibitors discovery. In this study, we carried out molecular docking, molecular dynamics simulations, molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) binding free energy calculations, principal component analysis (PCA), and dynamical cross-correlation matrices (DCCM) to dissect the molecular mechanism for the valmerin-19 acting as a dual inhibitor for glycogen synthase kinase 3β (GSK3β) and cyclin-dependent kinase 5 (CDK5). Detailed MM-PBSA calculations revealed that the binding free energies of the valmerin-19 to GSK3β/CDK5 were calculated to be ?12.60?±?2.28 kcal mol-1 and ?11.85?±?2.54 kcal mol-1, respectively, indicating that valmerin-19 has the potential to act as a dual inhibitor of GSK3β/CDK5. The analyses of PCA and DCCM results unraveled that binding of the valmerin-19 reduced the conformational dynamics of GSK3β/CDK5 and the valmerin-19 bound to GSK3β/CDK5 might occur mostly through a conformational selection mechanism. This study may be helpful for the future design of novel and potent dual GSK3β/CDK5 inhibitors.  相似文献   

4.
The structures of fully active cyclin-dependent kinase-2 (CDK2) complexed with ATP and peptide substrate, CDK2 after the catalytic reaction, and CDK2 inhibited by phosphorylation at Thr14/Tyr15 were studied using molecular dynamics (MD) simulations. The structural details of the CDK2 catalytic site and CDK2 substrate binding box were described. Comparison of MD simulations of inhibited complexes of CDK2 was used to help understand the role of inhibitory phosphorylation at Thr14/Tyr15. Phosphorylation at Thr14/Tyr15 causes ATP misalignment for the phosphate-group transfer, changes in the Mg2+ coordination sphere, and changes in the H-bond network formed by CDK2 catalytic residues (Asp127, Lys129, Asn132). The inhibitory phosphorylation causes the G-loop to shift from the ATP binding site, which leads to opening of the CDK2 substrate binding box, thus probably weakening substrate binding. All these effects explain the decrease in kinase activity observed after inhibitory phosphorylation at Thr14/Tyr15 in the G-loop. Interaction of the peptide substrate, and the phosphorylated peptide product, with CDK2 was also studied and compared. These results broaden hypotheses drawn from our previous MD studies as to why a basic residue (Arg/Lys) is preferred at the P+2 substrate position. Figure View of the substrate binding site of the fully active cyclin-dependent kinase-2 (CDK2) (pT160-CDK2/cyclin A/ATP). The pThr160 activation site is located in the T-loop (yellow secondary structure). The G-loop, which partly forms the ATP binding site, is shown in blue. The Thr14 and Tyr15 inhibitory phosphorylation sites located in the G-loop are shown in licorice representation  相似文献   

5.
Abstract

The p90 ribosomal s6 kinase 2 (RSK2) is a promising target because of its over expression and activation in human cancer cells and tissues. Over the last few years, significant efforts have been made in order to develop RSK2 inhibitors to treat myeloma, prostatic cancer, skin cancer and etc., but with limited success so far. In this paper, pharmacophore modelling, molecular docking study and molecular dynamics (MD) simulation have been performed to explore the novel inhibitors of RSK2. Pharmacophore models were developed by 95 molecules having pIC50 ranging from 4.577 to 9.000. The pharmacophore model includes one hydrogen bond acceptor (A), one hydrogen bond donor (D), one hydrophobic feature (H) and one aromatic ring (R). It is the best pharmacophore hypothesis that has the highest correlation coefficient (R2 = 0.91) and cross validation coefficient (Q2 = 0.71) at 5 component PLS factor. It was evaluated using enrichment analysis and the best model was used for virtual screening. The constraints used in this study were docking score, ADME properties, binding free energy estimates and IFD Score to screen the database. Ultimately, 12 hits were identified as potent and novel RSK2 inhibitors. A 15 ns molecular dynamics (MD) simulation was further employed to validate the reliability of the docking results.  相似文献   

6.
Cyclin-dependent kinase (CDK) inhibitor genes encode low molecular weight proteins which have important functions in cell cycle regulation, development and perhaps also in tumorigenesis. The first plant CDK inhibitor gene ICK1 was recently identified from Arabidopsis thaliana . Although the C-terminal domain of ICK1 contained an important consensus sequence with the mammalian CDK inhibitor p27Kip1, the remainder of the deduced ICK1 sequence showed little similarity to any known CDK inhibitors. In vitro assays showed that recombinant ICK1 exhibited unique kinase inhibitory properties. In the present study we characterized ICK1 in terms of its gene structure, its interaction with both A. thaliana Cdc2a and CycD3, and its induction by the plant growth regulator, abscisic acid (ABA). ICK1 was expressed at a relatively low level in the tissues surveyed. However, ICK1 was induced by ABA, and along with ICK1 induction there was a decrease in Cdc2-like histone H1 kinase activity. These results suggest a molecular mechanism by which plant cell division might be inhibited by ABA. ICK1 clones were also identified from independent yeast two-hybrid screens using the CycD3 construct. The implication that ICK1 protein could interact with both Cdc2a and CycD3 was confirmed by in vitro binding assays. Furthermore, deletion analysis indicated that different regions of ICK1 are required for the interactions with Cdc2a and CycD3. These results provide a mechanistic basis for understanding the role of CDK inhibitors in cell cycle regulation in plant cells.  相似文献   

7.
The cyclin-dependent kinases (CDKs) are critical regulators of cell cycle progression, and are involved in uncontrolled cell proliferation—a hallmark of cancer. This suggests that small molecular inhibitors of CDKs might be attractive as prospective antitumor agents. To explore the relationship between the structures of substituted isoquinoline-1,3-(2H,4H)-diones and their inhibition of CDK4, 3D-QSAR studies were performed on a dataset of 48 compounds. The bioactive conformation of template compound 34 was obtained by performing molecular docking into the ATP binding site of the homology model of CDK4 and ranking by highest consensus score, which was then used to build and align the rest of the molecules in the series. The constructed comparative molecular similarity indices analysis (CoMSIA) produces significantly better results than comparative molecular field analysis (CoMFA), with r\textcv2 r_{\text{cv}}^2 = 0.707 and r 2 = 0.988. The contours analysis provides useful information about the structural requirements for substituted isoquinoline-1,3-(2H,4H)-diones for CDK4 inhibitory activity.  相似文献   

8.
Ribonucleotide reductase (RNR) is necessary for production of the precursor deoxyribonucleotides for DNA synthesis. Class Ia RNR functions via a stable free radical in one of the two components protein R2. The enzyme mechanism involves long range (proton coupled) electron transfer between protein R1 and the tyrosyl radical in protein R2. Earlier experimental studies showed that p-alkoxyphenols inhibit RNR. Here, molecular docking and molecular dynamics simulations involving protein R2 suggest an inhibition mechanism for p-alkoxyphenols . A low energy binding pocket is identified in protein R2. The preferred configuration provides a structural basis explaining their specific binding to the Escherichia coli and mouse R2 proteins. Trp48 (E. coli numbering), on the electron transfer pathway, is involved in the interactions with the inhibitors. The relative order of the binding energies calculated for the phenol derivatives to protein R2 is correlated with earlier experimental data on inhibition efficiency, in turn related to increasing size of the hydrophobic alkyl substituents. Using the configuration identified by molecular docking as a starting point for molecular dynamics simulations, we find that the p-allyloxyphenol interrupts the catalytic electron transfer pathway of the R2 protein by forming hydrogen bonds with Trp48 and Asp237, thus explaining the inhibitory activity of p-alkoxyphenols.  相似文献   

9.
The interaction of fisetholz with bovine serum albumin (BSA) and human serum albumin (HSA) was investigated by multi-spectroscopic, cyclic voltammetric, and molecular docking technique. The results revealed that there was a static quenching of BSA/HSA induced by fisetholz. The binding constants (Ka) and binding sites (n) were calculated at different temperatures (293, 303, and 311?K). The enthalpy change (ΔH) were calculated to be –17.20?kJ mol?1 (BSA) and –18.28?kJ mol?1 (HSA) and the entropy change (ΔS) were calculated to be 35.41?J mol?1 (BSA) and 24.02?J mol?1 (HSA), respectively, which indicated that the interaction between fisetholz and BSA/HSA was mainly by electrostatic attraction. Based on displacement experiments using site probes, indomethacin and ibuprofen, the binding site of fisetholz to BSA/HSA was identified as sub-domain IIIA, which was further confirmed by molecular docking method. There was little effect of K+, Ca2+, Cu2+, Zn2+, and Fe3+ on fisetholz-BSA or fisetholz-HSA complex. The spectra of synchronous fluorescence, circular dichroism (CD) and Fourier transform infrared (FT-IR) all showed that fisetholz binding to BSA/HSA leads to secondary structures change of the two serum albumins. According to the Förster non-radiation energy transfer theory, the binding distance between fisetholz and BSA/HSA was 2.94/4.68?nm. The cyclic voltammetry as a supporting tool also indicated that fisetholz interacted with protein.

Communicated by Ramaswamy H. Sarma  相似文献   


10.
Abstract

A new series of benzothiazol-2-ylcarbamodithioate functional compounds 5a-f has been designed, synthesized and characterized by spectral data. These compounds were screened for their in vitro antibacterial activity against strains of Staphylococcus aureus (NCIM 5021, NCIM 5022 and methicillin-resistant isolate 43300), Bacillus subtilis (NCIM 2545), Escherichia coli (NCIM 2567), Klebsiella pneumoniae (NCIM 2706) and Psudomonas aeruginosa (NCIM 2036). Compounds 5a and 5d exhibited significant activity against all the tested bacterial strains. Specifically, compounds 5a and 5d showed potent activity against K. pneumoniae (NCIM 2706), while compound 5a also displayed potent activity against S. aureus (NCIM 5021). Compound 5d showed minimum IC50 value of 13.37?μM against S. aureus MurD enzyme. Further, the binding interactions of compounds 5a-f in the catalytic pocket have been investigated using the extra-precision molecular docking and binding free energy calculation by MM-GBSA approach. A 30?ns molecular dynamics simulation of 5d/modeled S. aureus MurD enzyme was performed to determine the stability of the predicted binding conformation.  相似文献   

11.
Cyclin‐dependent kinases (CDKs) are core components of the cell cycle machinery that govern the transition between phases during cell cycle progression. Abnormalities in CDKs activity and regulation are common features of cancer, making CDK family members attractive targets for the development of anticancer drugs. Their inhibitors have entered in clinical trials to treat cancer. Very recently, Heathcote et al. (J. Med. Chem. 2010, 53:8508–8522) have found a ligand BS194 that has a high affinity with CDK2 (IC50 = 3 nm ) but shows low affinity with CDK1 (IC50 = 30 nm ). To understand the selectivity, we used homology modeling, molecular docking, molecular dynamics, and free‐energy calculation to analyze the interactions. A rational three‐dimensional model of the CDK1/BS194 complex is built. We found that Leu83 is a key residue that recognizes BS194 more effectively with CDK2 with good binding free energies rather than CDK1. Energetic analysis reveals that van der Waals interaction and non‐polar contributions to solvent are favorable in the formation of complexes and amine group of the ligand, which plays a crucial role for binding selectivity between CDK2 and CDK1. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

12.
The stability and dynamics of a double-stranded DNA (dsDNA) is affected by the preferential occupancy of small monovalent molecular ions. Small metal and molecular ions such as sodium and alkyl ammonium have crucial biological functions in human body, affect the thermodynamic stability of the duplex DNA and exhibit preferential binding. Here, using atomistic molecular dynamics simulations, we investigate the preferential binding of metal ion such as Na+ and molecular ions such as tetramethyl ammonium (TMA+) and 2-hydroxy-N,N,N-trimethylethanaminium (CHO+) to double-stranded DNA. The thermodynamic driving force for a particular molecular ion-DNA interaction is determined by decomposing the free energy of binding into its entropic and enthalpic contributions. Our simulations show that each of these molecular ions preferentially binds to the minor groove of the DNA and the extent of binding is highest for CHO+. The ion binding processes are found to be entropically favourable. In addition, the contribution of hydrophobic effects towards the entropic stabilisation (in case of TMA+) and the effect of hydrogen bonding contributing to enthalpic stabilisation (in case of CHO+) have also been investigated.  相似文献   

13.
Wee1-like protein kinase (Wee1) is a tyrosine kinase that regulates the G2 checkpoint and prevents entry into mitosis in response to DNA damage. Based on a series of signaling pathways initiated by Wee1, Wee1 has been recognized as a potential target for cancer therapy. To discover potent Wee1 inhibitors with novel scaffolds, ligand-based pharmacophore model has been built based on 101 known Wee1 inhibitors. Then the best pharmacophore model, AADRRR.340, with good partial least square (PLS) statistics (R2?=?0.9212, Q2?=?0.7457), was selected and validated. The validated model was used as a three-dimensional (3D) search query for databases virtual screening. The filtered molecules were further analyzed and refined by Lipinski’s rule of 5, multiple docking procedures (high throughput virtual screening (HTVS), standard precision (SP), genetic optimization for ligand docking (GOLD), extra precision (XP), and unique quantum polarized ligand docking (QPLD)); absorption, distribution, metabolism, excretion, and toxicity (ADMET) screening; and the Prime/molecular mechanics generalized born surface area (MM-GBSA) method binding free energy calculations. Eight leads were identified as potential Wee1 inhibitors, and a 50?ns molecular dynamics (MD) simulation was carried out for top four inhibitors to predict the stability of ligand–protein complex. Molecular mechanics Poisson–Boltzmann surface area (MM-PBSA) based on MD simulation and the energy contribution per residue to the binding energy were calculated. In the end, three hits with good stabilization and affinity to protein were identified.

Communicated by Ramaswamy H. Sarma  相似文献   


14.
Abstract

Most of the drugs binding to human serum albumin (HSA) are transported to various parts of the body. Here, we have studied the molecular interaction between HSA and synthesized uridine derivatives, 1-[(3R, 4S, 5?R)-2-methyl-3, 4-dihydroxy-5-(hydroxymethyl)oxolan-2-yl]pyrimidine-2,4-dion.)(C-MU); [(2R,3R,4R,5R)-5-(2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)-3,4-dihydroxy-4-methyl-tetrahydrofuran-2-yl] methyl methyl phosphochloridate (CM-MU) and [(2R,3S,4R,5R)-5-(2,4-dioxopyrimidin-1-yl)-2-methyl-3,4-dihydroxyoxolan-2-yl] methyl dihydrogen phosphate (P-MU). Cytotoxic studies of these synthesized compounds with mouse macrophages (RAW 246.7) and HeLa cells (human cervical cancer cells) and binding mechanism of these uridine derivatives with HSA were performed. Subsequently, fluorescence quenching was observed upon titration of uridine derivatives with HSA via static mode of quenching, and the binding constants (K2-C-MU = 4?±?0.03?×?104M?1, K5-CM-MU = 1.95?±?0.03?×?104 M?1 and K5-P-MU =1.56?±?0.03?×?104 M?1) were found to be in sync with the computational results. Further, molecular displacement and molecular docking data revealed that all the derivatives are binding in the subdomain IIA and IIB regions of HSA. The protein secondary structure of complexes was determined by circular dichroism, indicating partial unfolding of the protein upon addition of the uridine derivatives. Furthermore, atomic force microscopy data reveal the change in topology upon binding of 2-C-MU, 5-CM-MU and 5-P-MU with HSA, indicating change in the microenvironment around tryptophan region. Additionally, cytotoxicity studies on HeLa and Raw Cell lines suggested that these molecules have significant anti-proliferative and anti-inflammatory properties. Hence, the study may be of help for development of new drugs based on uridine derivatives which may be helpful for combating various potential diseases.

Communicated by Ramaswamy H. Sarma  相似文献   

15.
16.
Abstract

Cyclin-dependent kinase 2 (CDK2) is the family of Ser/Thr protein kinases that has emerged as a highly selective with low toxic cancer therapy target. A multistage virtual screening method combined by SVM, protein-ligand interaction fingerprints (PLIF) pharmacophore and docking was utilised for screening the CDK2 inhibitors. The evaluation of the validation set indicated that this method can be used to screen large chemical databases because it has a high hit-rate and enrichment factor (80.1% and 332.83 respectively). Six compounds were screened out from NCI, Enamine and Pubchem database. After molecular dynamics and binding free energy calculation, two compounds had great potential as novel CDK2 inhibitors and they also showed selective inhibition against CDK2 in the kinase activity assay.  相似文献   

17.
Abstract

The over-activation of Ras/mitogen-activated protein kinase (MAPK) signaling pathway associated with a variety of cancers is usually related with abnormal activation of Src-homology 2 domain-containing protein tyrosine phosphatase (SHP2). For this purpose, SHP2 has attracted extensive interest as a potential target for cancer treatment. RMC-4550, as a newly developed selective inhibitor of SHP2, possesses an overwhelming advantage over the previous generation inhibitor SHP099 in terms of in vitro activity. However, the binding mode of SHP2 with RMC-4550 and the reason for the high efficiency of RMC-4550 as SHP2 inhibitor at molecular level are still unclear. Therefore, in this study, the binding mode of RMC-4550 with SHP2 and the superiorities of RMC-4550 as inhibitor at binding affinity and dynamic interactive behavior with SHP2 were probed by molecular docking and molecular dynamics (MD) simulations. By comparing the results of molecular docking, it was found that SHP2 formed more tight interaction with RMC-4550 than that with SHP099. Subsequently, a series of post-dynamic analyses on three simulation trajectories (SHP2WT, SHP2SHP099 and SHP2RMC-4550) were performed and found that the SHP2 protein bound with RMC-4550 maintained a firmer interaction between N-Src-homology 2 (N-SH2) and PTP domain throughout the MD simulation, leading to a more stable protein conformation. The finding here provides new clues for the design of SHP2 inhibitor against the over-activation of Ras/MAPK pathway.

Communicated by Ramaswamy H. Sarma  相似文献   

18.
19.
An efficient synthesis of substituted pyrido[2,3-d]pyrimidines was carried out and evaluated for in vitro anticancer activity against five cancer cell lines, namely hepatic cancer (HepG-2), prostate cancer (PC-3), colon cancer (HCT-116), breast cancer (MCF-7), and lung cancer (A-549) cell lines. Regarding HepG-2, PC-3, HCT-116 cancer cell lines, 7-(4-chlorophenyl)-2-(3-methyl-5-oxo-2,3-dihydro-1H-pyrazol-1-yl)-5-(p-tolyl)- pyrido[2,3-d]pyrimidin-4(3H)-one (5a) exhibited strong, more potent anticancer (IC50: 0.3, 6.6 and 7?µM) relative to the standard doxorubicin (IC50: 0.6, 6.8 and 12.8?µM), respectively. Kinase inhibitory assessment of 5a showed promising inhibitory activity against three kinases namely PDGFR β, EGFR, and CDK4/cyclin D1 at two concentrations 50 and 100?µM in single measurements. Further, a molecular docking study for compound 5a was performed to verify the binding mode towards the EGFR and CDK4/cyclin D1 kinases.  相似文献   

20.
Filamentous temperature-sensitive protein Z (FtsZ) is a protein encoded by the FtsZ gene that assembles into a Z-ring at the future site of the septum of bacterial cell division. Structurally, FtsZ is a homolog of eukaryotic tubulin but has low sequence similarity; this makes it possible to obtain FtsZ inhibitors without affecting the eukaryotic cell division. Computational studies were performed on a series of substituted 3-arylalkoxybenzamide derivatives reported as inhibitors of FtsZ activity in Staphylococcus aureus. Quantitative structure-activity relationship models (QSAR) models generated showed good statistical reliability, which is evident from r2ncv and r2loo values. The predictive ability of these models was determined and an acceptable predictive correlation (r2Pred) values were obtained. Finally, we performed molecular dynamics simulations in order to examine the stability of protein-ligand interactions. This facilitated us to compare free binding energies of cocrystal ligand and newly designed molecule B1. The good concordance between the docking results and comparative molecular field analysis (CoMFA)/comparative molecular similarity indices analysis (CoMSIA) contour maps afforded obliging clues for the rational modification of molecules to design more potent FtsZ inhibitors.  相似文献   

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