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1.
Int J Mol Sci ; 25(11)2024 Jun 04.
Article in English | MEDLINE | ID: mdl-38892388

ABSTRACT

SHP2, a pivotal component downstream of both receptor and non-receptor tyrosine kinases, has been underscored in the progression of various human cancers and neurodevelopmental disorders. Allosteric inhibitors have been proposed to regulate its autoinhibition. However, oncogenic mutations, such as E76K, convert SHP2 into its open state, wherein the catalytic cleft becomes fully exposed to its ligands. This study elucidates the dynamic properties of SHP2 structures across different states, with a focus on the effects of oncogenic mutation on two known binding sites of allosteric inhibitors. Through extensive modeling and simulations, we further identified an alternative allosteric binding pocket in solution structures. Additional analysis provides insights into the dynamics and stability of the potential site. In addition, multi-tier screening was deployed to identify potential binders targeting the potential site. Our efforts to identify a new allosteric site contribute to community-wide initiatives developing therapies using multiple allosteric inhibitors to target distinct pockets on SHP2, in the hope of potentially inhibiting or slowing tumor growth associated with SHP2.


Subject(s)
Allosteric Site , Neoplasms , Protein Tyrosine Phosphatase, Non-Receptor Type 11 , Protein Tyrosine Phosphatase, Non-Receptor Type 11/antagonists & inhibitors , Protein Tyrosine Phosphatase, Non-Receptor Type 11/metabolism , Protein Tyrosine Phosphatase, Non-Receptor Type 11/chemistry , Humans , Neoplasms/drug therapy , Neoplasms/metabolism , Allosteric Regulation/drug effects , Mutation , Binding Sites , Antineoplastic Agents/pharmacology , Antineoplastic Agents/chemistry , Antineoplastic Agents/therapeutic use , Protein Binding , Molecular Dynamics Simulation
2.
J Chem Inf Model ; 63(5): 1602-1614, 2023 03 13.
Article in English | MEDLINE | ID: mdl-36800279

ABSTRACT

Phosphorylation of proteins plays an important regulatory role at almost all levels of cellular organization. Molecular dynamics (MD) simulation is a promising tool to reveal the mechanism of how phosphorylation regulates many key biological processes at the atomistic level. MD simulation accuracy depends on force field precision, while the current force fields for phospho-amino acids have resulted in notable inconsistency with experimental data. Here, a new force field parameter (named FB18CMAP) is generated by fitting against quantum mechanics (QM) energy in aqueous solution with φ/ψ dihedral potential-energy surfaces optimized using CMAP parameters. MD simulations of phosphorylated dipeptides, intrinsically disordered proteins (IDPs), and ordered (folded) proteins show that FB18CMAP can mimic NMR observables and structural characteristics of phosphorylated dipeptides and proteins more accurately than the FB18 force field. These findings suggest that FB18CMAP performs well in both the simulation of ordered and disordered states of phosphorylated proteins.


Subject(s)
Intrinsically Disordered Proteins , Phosphoproteins , Protein Conformation , Phosphorylation , Molecular Dynamics Simulation , Intrinsically Disordered Proteins/chemistry , Dipeptides/chemistry
3.
Nucleic Acids Res ; 49(D1): D1218-D1224, 2021 01 08.
Article in English | MEDLINE | ID: mdl-32941628

ABSTRACT

Infertility is a complex multifactorial disease that affects up to 10% of couples across the world. However, many mechanisms of infertility remain unclear due to the lack of studies based on systematic knowledge, leading to ineffective treatment and/or transmission of genetic defects to offspring. Here, we developed an infertility disease database to provide a comprehensive resource featuring various factors involved in infertility. Features in the current IDDB version were manually curated as follows: (i) a total of 307 infertility-associated genes in human and 1348 genes associated with reproductive disorder in 9 model organisms; (ii) a total of 202 chromosomal abnormalities leading to human infertility, including aneuploidies and structural variants; and (iii) a total of 2078 pathogenic variants from infertility patients' samples across 60 different diseases causing infertility. Additionally, the characteristics of clinically diagnosed infertility patients (i.e. causative variants, laboratory indexes and clinical manifestations) were collected. To the best of our knowledge, the IDDB is the first infertility database serving as a systematic resource for biologists to decipher infertility mechanisms and for clinicians to achieve better diagnosis/treatment of patients from disease phenotype to genetic factors. The IDDB is freely available at http://mdl.shsmu.edu.cn/IDDB/.


Subject(s)
Chromosome Aberrations , Databases, Factual , Endocrine System Diseases/genetics , Infertility, Female/genetics , Infertility, Male/genetics , Mutation , Animals , Chromosome Mapping , Disease Models, Animal , Endocrine System Diseases/metabolism , Endocrine System Diseases/pathology , Female , Gene Expression Profiling , Gene Expression Regulation , Genetic Predisposition to Disease , Genome, Human , Humans , Infertility, Female/metabolism , Infertility, Female/pathology , Infertility, Male/metabolism , Infertility, Male/pathology , Internet , Male , Oocytes/metabolism , Oocytes/pathology , Software , Spermatozoa/metabolism , Spermatozoa/pathology
4.
Arch Pharm (Weinheim) ; 356(1): e2200400, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36284484

ABSTRACT

Herein, a library of novel pyridone derivatives 1-34 was designed, synthesized, and evaluated for α-amylase and α-glucosidase inhibitory as well as antioxidant activities. Pyridone derivatives 1-34 were synthesized via a one-pot multi-component reaction of variously substituted aromatic aldehydes, acetophenone, ethyl cyanoacetate, and ammonium acetate in absolute ethanol. Synthetic compounds 1-34 were structurally characterized by different spectroscopic techniques. Most of the tested compounds showed more promising inhibition potential than the standard acarbose (IC50 = 14.87 ± 0.16 µM) but compounds 13 and 12 were found to be the most potent compounds with IC50 values of 9.20 ± 0.14 µM and 3.05 ± 0.18 µM against α-amylase and α-glucosidase enzymes, respectively. Compounds 1-34 also displayed moderate antioxidant potential in the range of IC50 = 96.50 ± 0.45 to 189.98 ± 1.00 µM in comparison to the control butylated hydroxytoluene (BHT) (IC50 = 66.50 ± 0.36 µM), in DPPH radical scavenging activities. Additionally, all synthetic derivatives were subjected to a molecular docking study to investigate the interaction details of compounds 1-34 (ligands) with the active site of enzymes (receptors). These results indicate that the newly synthesized pyridone class may serve as promising lead candidates for controlling diabetes mellitus and as antioxidants.


Subject(s)
Antioxidants , alpha-Glucosidases , Antioxidants/pharmacology , Antioxidants/chemistry , alpha-Glucosidases/metabolism , Structure-Activity Relationship , Molecular Docking Simulation , alpha-Amylases , Glycoside Hydrolase Inhibitors/pharmacology , Glycoside Hydrolase Inhibitors/chemistry
5.
Molecules ; 28(3)2023 Jan 29.
Article in English | MEDLINE | ID: mdl-36770965

ABSTRACT

Infection of hepatitis C (HCV) is a major threat to human health throughout the world. The current therapy program suffers from restricted efficiency and low tolerance, and there is serious demand frr novel medication. NS3/4A protease is observed to be very effective target for the treatment of HCV. A data set of the already reported HCV NS3/4A protease inhibitors was first docked into the NS3/4A protease (PDB ID: 4A92A) active sites of both protease and helicase sites for calculating the docking score, binding affinity, binding mode, and solvation energy. Then the data set of these reported inhibitors was used in a computer-based program "RECAP Analyses" implemented in MOE to fragment every molecule in the subset according to simple retrosynthetic analysis rules. The RECAP analysis fragments were then used in another computer-based program "RECAP Synthesis" to randomly recombine and generate synthetically reasonable novel chemical structures. The novel chemical structures thus produced were then docked against HCV NS3/4A. After a thorough validation of all undertaken steps, based on Lipinski's rule of five, docking score, binding affinity, solvation energy, and Van der Waal's interactions with HCV NS3/4A, 12 novel chemical structures were identified as inhibitors of HCV NS3/4A. The novel structures thus designed are hoped to play a key role in the development of new effective inhibitors of HCV.


Subject(s)
Hepatitis C , Molecular Dynamics Simulation , Humans , Endopeptidases/metabolism , Hepacivirus , Hepatitis C/drug therapy , Catalytic Domain , Viral Nonstructural Proteins/metabolism , Protease Inhibitors/chemistry , Antiviral Agents/chemistry
6.
Mol Divers ; 26(2): 849-868, 2022 Apr.
Article in English | MEDLINE | ID: mdl-33650031

ABSTRACT

A variety of dihydroquinazolin-4(1H)-one derivatives (1-37) were synthesized via "one-pot" three-component reaction scheme by treating aniline and different aromatic aldehydes with isatoic anhydride in the presence of acetic acid. Chemical structures of compounds were deduced by different spectroscopic techniques including EI-MS, HREI-MS, 1H-, and 13C-NMR. Compounds were subjected to α-amylase and α-glucosidase inhibitory activities. A number of derivatives exhibited significant to moderate inhibition potential against α-amylase (IC50 = 23.33 ± 0.02-88.65 ± 0.23 µM) and α-glucosidase (IC50 = 25.01 ± 0.12-89.99 ± 0.09 µM) enzymes, respectively. Results were compared with the standard acarbose (IC50 = 17.08 ± 0.07 µM for α-amylase and IC50 = 17.67 ± 0.09 µM for α-glucosidase). Structure-activity relationship (SAR) was rationalized by analyzing the substituents effects on inhibitory potential. Kinetic studies were implemented to find the mode of inhibition by compounds which revealed competitive inhibition for α-amylase and non-competitive inhibition for α-glucosidase. However, in silico study identified several important binding interactions of ligands (synthetic analogues) with the active site of both enzymes.


Subject(s)
Diabetes Mellitus , alpha-Glucosidases , Glycoside Hydrolase Inhibitors/chemistry , Glycoside Hydrolase Inhibitors/pharmacology , Humans , Kinetics , Magnetic Resonance Spectroscopy , Molecular Docking Simulation , alpha-Amylases/metabolism , alpha-Glucosidases/chemistry
7.
Molecules ; 27(13)2022 Jun 30.
Article in English | MEDLINE | ID: mdl-35807475

ABSTRACT

Reaction of two equivalents of the bulky 1,3-bis(2,6-diethylphenyl)thiourea ligand (L) with MX (being M = Cu+, Ag+; and X = Cl-, Br-, I-) in acetonitrile afforded neutral complexes of the type [MXL2] [CuClL2].2CH3CN (1a); [CuBrL2].2CH3CN (1b); [CuIL2] (1c): [AgClL2] (2a); [AgBrL2] (2b) and [AgIL2] (2c). The two aromatic groups in free ligand were found to be trans with respect to the thiourea unit, which was a reason to link the ligand molecules via intermolecular hydrogen bonding. Intramolecular hydrogen bonding was observed in all metal complexes. The copper complexes 1a and 1b are acetonitrile solvated and show not only intra- but also intermolecular hydrogen bonding between the coordinated thiourea and the solvated acetonitrile molecules. Silver complexes reported here are the first examples of structurally characterized tricoordinated thiourea-stabilized monomeric silver(I) halides. Molecular docking studies were carried out to analyze the binding modes of the metal complexes inside the active site of the human insulin (HI) protein. Analysis of the docked conformations revealed that the electrostatic and aromatic interactions of the protein N-terminal residues (i.e., Phe and His) may assist in anchoring and stabilizing the metal complexes inside the active site. According to the results of docking studies, the silver complexes exhibited the strongest inhibitory capability against the HI protein, which possesses a deactivating group, directly bonded to silver. All compounds were fully characterized by elemental analysis, NMR spectroscopy, and molecular structures of the ligand, and five out of six metal complexes were also confirmed by single-crystal X-ray diffraction.


Subject(s)
Coordination Complexes , Insulins , Acetonitriles , Coordination Complexes/chemistry , Copper/chemistry , Crystallography, X-Ray , Humans , Ligands , Molecular Docking Simulation , Silver/chemistry , Thiourea/chemistry
8.
Phys Chem Chem Phys ; 23(21): 12127-12136, 2021 Jun 02.
Article in English | MEDLINE | ID: mdl-34032235

ABSTRACT

Intrinsically disordered proteins (IDPs) have no fixed tertiary structure under physiological conditions and are associated with many human diseases. Because IDPs have the characteristic of possessing diverse conformations, current experimental methods cannot capture all the conformations of IDPs. However, molecular dynamics simulation can sample these atomistically diverse conformations as a valuable complement to experimental data. To accurately describe the properties of IDPs, the environment-specific precise force field (ESFF1) was successfully released to reproduce the conformer character of ordered and disordered proteins. Here, three typical IDPs and thirteen folded proteins were used to further evaluate the performance of this force field. The results indicate that the NMR observables of ESFF1 better approach experimental data than do those of ff14SB for IDPs. The sampling conformations by ESFF1 are more diverse than those of ff14SB. For folded proteins, these force fields have comparable performances for reproducing conformers. Therefore, ESFF1 can be used to reveal the model of sequence-disorder-function for IDPs.


Subject(s)
Intrinsically Disordered Proteins/chemistry , Humans , Molecular Dynamics Simulation , Nuclear Magnetic Resonance, Biomolecular , Protein Conformation , Protein Folding
9.
Phys Chem Chem Phys ; 23(21): 12204-12215, 2021 Jun 02.
Article in English | MEDLINE | ID: mdl-34008604

ABSTRACT

Hepatitis C virus (HCV) is a notorious member of the Flaviviridae family of enveloped, positive-strand RNA viruses. Non-structural protein 5A (NS5A) plays a key role in HCV replication and assembly. NS5A is a multi-domain protein which includes an N-terminal amphipathic membrane anchoring alpha helix, a highly structured domain-1, and two intrinsically disordered domains 2-3. The highly structured domain-1 contains a zinc finger (Zf)-site, and binding of zinc stabilizes the overall structure, while ejection of this zinc from the Zf-site destabilizes the overall structure. Therefore, NS5A is an attractive target for anti-HCV therapy by disulfiram, through ejection of zinc from the Zf-site. However, the zinc ejection mechanism is poorly understood. To disclose this mechanism based on three different states, A-state (NS5A protein), B-state (NS5A + Zn), and C-state (NS5A + Zn + disulfiram), we have performed molecular dynamics (MD) simulation in tandem with DFT calculations in the current study. The MD results indicate that disulfiram triggers Zn ejection from the Zf-site predominantly through altering the overall conformation ensemble. On the other hand, the DFT assessment demonstrates that the Zn adopts a tetrahedral configuration at the Zf-site with four Cys residues, which indicates a stable protein structure morphology. Disulfiram binding induces major conformational changes at the Zf-site, introduces new interactions of Cys39 with disulfiram, and further weakens the interaction of this residue with Zn, causing ejection of zinc from the Zf-site. The proposed mechanism elucidates the therapeutic potential of disulfiram and offers theoretical guidance for the advancement of drug candidates.


Subject(s)
Antiviral Agents/pharmacology , Disulfiram/pharmacology , Hepacivirus/drug effects , Viral Nonstructural Proteins/antagonists & inhibitors , Zinc/pharmacology , Antiviral Agents/chemical synthesis , Antiviral Agents/chemistry , Density Functional Theory , Disulfiram/chemistry , Humans , Molecular Dynamics Simulation , Zinc/chemistry
10.
Microb Pathog ; 146: 104245, 2020 Sep.
Article in English | MEDLINE | ID: mdl-32423883

ABSTRACT

The emergence of carbapenem-resistant Klebsiella Pneumoniae had been reported previously, which needs rapid attention. Currently, Pittsburgh University Hospital reported a new strain of carbapenem-resistant Klebsiella pneumoniae that was co-producing OXA-232 and NDM-1 named as PittNDM01. This strain is resistant to almost all beta-lactam antibiotics such as Carbapenem as well as to fluoroquinolones and aminoglycosides. Globally, failure to the wide-spread pathogenic strains had been observed due to the increased and antibiotic resistance, which leads to less antimicrobial drug efficacy. Since last decades, computational genomic approaches have been introduced to fight against resistant pathogens, which is an advanced approach for novel drug targets investigation. The current study emphasizes the utilization of the available genomic and proteomic data of Klebsiella pneumoniae PittNDM01 for the identification of novel drug targets for future drug developments. Comparative genomic analysis and molecular biological tools were applied, results in observing 582 non-human homologous-essential proteins of Klebsiella pneumoniae. Among the total 582 proteins, 66 were closely related to the pathogen-specific pathway. Out of all 66-targeted proteins, ten non-homologous essential proteins were found to have druggability potential. The subcellular localization of these proteins revealed; 6 proteins in the cytoplasm, 2 in the inner membrane, and one each in periplasmic space and outer membrane. All the above 10 proteins were compared to the proteins sequences of gut flora to eliminate the homologous proteins. In total, 6-novel non-human and non-gut flora essential drug targets of Klebsiella pneumoniae PittNDM01 strain were identified. Further, the 3D structures of the identified drug target proteins were developed, and protein-protein interaction network analysis was performed to know the functional annotation of the desire proteins. Therefore, these non-homologous essential targets ensure the survival of the pathogen and hence can be targeted for drug discovery.


Subject(s)
Drug Delivery Systems/methods , Proteome/genetics , beta-Lactamases/genetics , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Carbapenem-Resistant Enterobacteriaceae , Computer Simulation , Gene Ontology , Genome, Bacterial , Humans , Klebsiella Infections/drug therapy , Klebsiella pneumoniae/genetics , Protein Interaction Maps
11.
J Chem Inf Model ; 60(10): 4912-4923, 2020 10 26.
Article in English | MEDLINE | ID: mdl-32816485

ABSTRACT

Molecular dynamics (MD) simulations of six upgraded empirical force fields were compared and evaluated with short peptides, intrinsically disordered proteins, and folded proteins using trajectories of 1, 1.5, 5, or 10 µs (five replicates of 200 ns, 300 ns, 1 µs, or 2 µs) for each system. Previous studies have shown that different force fields, water models, simulation methods, and parameters can affect simulation outcomes. Here, the MD simulations were done in an explicit solvent with RS-peptide, HEWL19, HIV-rev, ß amyloid (Aß)-40, Aß-42, phosphodiesterase-γ, CspTm, and ubiquitin using ff99IDPs, ff14IDPs, ff14IDPSFF, ff03w, CHARMM36m, and CHARMM22* force fields. The IDP ensembles generated by six all-atom empirical force fields were compared against NMR data. Despite using identical starting structures and simulation parameters, ensembles obtained with different force fields exhibit significant differences in NMR RMDs, secondary structure contents, and global properties such as the radius of gyration. The intrinsically disordered protein (IDP)-specific force fields could substantially reproduce the experimental observables in force field comparison: they have the lowest error in chemical shifts and J-couplings for short peptides/proteins, reasonably well for large IDPs and reasonably well with the radius of gyration. A high population of disorderness was observed in the IDP-specific force field for the IDP ensemble with a fraction of ß sheets for ß-amyloids. CHARMM22* performs better for many observables; however, it still has a preference toward the helicity for short peptides. The results of ß-amyloid 42 starting from two different initial structures (Aß421Z0Q and Aß42model) were also compared with DSSP and NMR data. The results obtained with IDP-specific force fields within 2 µs simulation time are similar, even though starting from different structures. The current force fields perform equally well for folded proteins. The results of currently developed or modified force fields for IDPs are capable of enlightening the overall performance of the force field for disordered as well as folded proteins, thereby contributing to force field development.


Subject(s)
Intrinsically Disordered Proteins , Amyloid beta-Peptides , Molecular Dynamics Simulation , Protein Conformation , Water
12.
Bioorg Chem ; 94: 103195, 2020 01.
Article in English | MEDLINE | ID: mdl-31451297

ABSTRACT

The current study describes the discovery of novel inhibitors of α-glucosidase and α-amylase enzymes. For that purpose, new hybrid analogs of N-hydrazinecarbothioamide substituted indazoles 4-18 were synthesized and fully characterized by EI-MS, FAB-MS, HRFAB-MS, 1H-, and 13C NMR spectroscopic techniques. Stereochemistry of the imine double bond was established by NOESY measurements. All derivatives 4-18 with their intermediates 1-3, were evaluated for in vitro α-glucosidase and α-amylase enzyme inhibition. It is worth mentioning that all synthetic compounds showed good inhibition potential in the range of 1.54 ±â€¯0.02-4.89 ±â€¯0.02 µM for α-glucosidase and for α-amylase 1.42 ±â€¯0.04-4.5 ±â€¯0.18 µM in comparison with the standard acarbose (IC50 value of 1.36 ±â€¯0.01 µM). In silico studies were carried out to rationalize the mode of binding interaction of ligands with the active site of enzymes. Moreover, enzyme inhibitory kinetic characterization was also performed to understand the mechanism of enzyme inhibition.


Subject(s)
Enzyme Inhibitors/chemical synthesis , Glycoside Hydrolase Inhibitors/chemical synthesis , Indazoles/chemistry , alpha-Amylases/antagonists & inhibitors , Computer Simulation , Enzyme Inhibitors/chemistry , Enzyme Inhibitors/pharmacology , Glycoside Hydrolase Inhibitors/chemistry , Glycoside Hydrolase Inhibitors/pharmacology , In Vitro Techniques , Kinetics , Magnetic Resonance Spectroscopy , Molecular Docking Simulation , Molecular Structure , Structure-Activity Relationship
13.
Bioorg Chem ; 104: 104238, 2020 11.
Article in English | MEDLINE | ID: mdl-32911195

ABSTRACT

Thirty benzofuran-2-yl(phenyl)methanones 1-30 were synthesized and characterized their structures by spectroscopic techniques. Substituted phenacyl bromide and different derivatives of 2-hydroxy-benzaldehyde treated in the presence of anhydrous K2CO3 in acetonitrile at room temperature to afford the desired benzofurans 1-30. All compounds were screened for their in vitro α-amylase inhibitory and radical scavenging (DPPH and ABTS) activities. Results revealed that para substituted compounds were found to be more active than the others with IC50 values ranges for α-amylase inhibition (IC50 = 18.04-48.33 µM), DPPH (IC50 = 16.04-32.33 µM) and ABTS (IC50 = 16.99-33.01 µM) radical scavenging activities. Activities results were compared with the standards acarbose (IC50 = 16.08 ± 0.07 µM) for α-amylase, ascorbic acid (IC50 = 15.08 ± 0.03 and 15.09 ± 0.17 µM) for DPPH and ABTS radical scavenging activities, respectively. Kinetic studies predicted that all compounds followed non-competitive mechanism of inhibition. Molecular docking results showed good protein-ligand interactions profile against the corresponding target. To the best of our knowledge, out of thirty molecules, ten compounds 18-20, 22, and 25-30 were structurally new.


Subject(s)
Benzofurans/pharmacology , Enzyme Inhibitors/pharmacology , Free Radical Scavengers/pharmacology , Molecular Docking Simulation , alpha-Amylases/antagonists & inhibitors , Benzofurans/chemical synthesis , Benzofurans/chemistry , Benzothiazoles/antagonists & inhibitors , Biphenyl Compounds/antagonists & inhibitors , Dose-Response Relationship, Drug , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Free Radical Scavengers/chemical synthesis , Free Radical Scavengers/chemistry , Kinetics , Molecular Structure , Picrates/antagonists & inhibitors , Structure-Activity Relationship , Sulfonic Acids/antagonists & inhibitors , alpha-Amylases/metabolism
14.
Bioorg Chem ; 94: 103410, 2020 01.
Article in English | MEDLINE | ID: mdl-31732193

ABSTRACT

Over-expression of α-amylase enzyme causes hyperglycemia which lead to many physiological complications including oxidative stress, one of the most commonly associated problem with diabetes mellitus. Marketed α-amylase inhibitors such as acarbose, voglibose, and miglitol used to treat type-II diabetes mellitus, but also linked to several harmful effects. Therefore, it is essential to explore new and nontoxic antidiabetic agents with additional antioxidant properties. In this connection, a series of new N-sulfonohydrazide substituted indazoles 1-19 were synthesized by multistep reaction scheme and assessed for in vitro α-amylase inhibitory and radical (DPPH and ABTS) scavenging properties. All compounds were fully characterized by different spectroscopic techniques including 1H, 13C NMR, EI-MS, HREI-MS, ESI-MS, and HRESI-MS. Compounds showed promising α-amylase inhibitory activities (IC50 = 1.23 ±â€¯0.06-4.5 ±â€¯0.03 µM) as compared to the standard acarbose (IC50 1.20 ±â€¯0.09 µM). In addition to that all derivatives were found good to moderate scavengers of DPPH (IC50 2.01 ±â€¯0.13-5.3 ±â€¯0.11) and ABTS (IC50 = 2.34 ±â€¯0.07-5.5 ±â€¯0.07 µM) radicals, in comparison with standard ascorbic acid having scavenging activities with IC50 = 1.99 ±â€¯0.09 µM, and IC50 2.03 ±â€¯0.11 µM for DPPH and ABTS radicals. In silico molecular docking study was conducted to rationalize the binding interaction of α-amylase enzyme with ligands. Compounds were observed as mixed type inhibitors in enzyme kinetic characterization.


Subject(s)
Indazoles/chemistry , Indazoles/chemical synthesis , Molecular Docking Simulation/methods , alpha-Amylases/antagonists & inhibitors , Humans , Molecular Structure
15.
J Chem Inf Model ; 59(4): 1584-1597, 2019 04 22.
Article in English | MEDLINE | ID: mdl-30810312

ABSTRACT

Pyrazinamide (PZA) is an essential first line antitubercular drug, which plays a crucial role in tuberculosis treatment. The PZA, which is considered as a pro-drug needs an enzyme of mycobacterial pyrazinamidase (PZase) for its conversion into an active form pyrazinoic acid. Further, this active form of PZA inhibits the ribosomal proteins S1, which facilitates the transfer-mRNA complex formation throughout the translation. The spontaneous mutations in RpsA have been found to be associated with PZA drug resistance. However, the drug resistance mechanism is still unclear. Furthermore, there is no such information available about the structural dynamics of RpsA protein because of mutations that confer Pyrazinoic acid resistance. Moreover, a total of 18 clinical PZA-resistant isolates were investigated and found to be pncAWT, which allowed exploration of the resistance mechanism of RpsA in the mutated state. Samples were repeated for the drug susceptibility testing followed by RpsA gene sequencing. A total of 11 clinical isolates harbored a total of 15 mutations. Almost half of the total strains (7/15) were observed to be in the conserved region of RpsA and known as Mycobacterium tuberculosis C-terminal domain. In the current study, (2/7) mutation T370P (mutant 1) and W403G (mutant 2) were explored to ensure the RpsA resistance mechanism through essential dynamics simulation. The essential dynamics study results revealed that the distal loop mutations drastically altered the conformation of RpsA both in the absence (-) and presence (+) of pyrazinoic acid drug for two reasons: (1) dramatic alteration or reduction in the binding pattern of pyrazinoic acid with active site residues observed and (2) a clear image of the opening and closing switching mechanism was seen upon the distal site mutation on nearby 310-helixes beside the pyrazinoic acid binding site. This switch was found to consistently remain closed only in wild type systems, while it was open in the mutant systems. We called such distance impact an "allosteric effect." The overall mechanistic investigations will provide useful information behind drug resistance for better understanding to manage tuberculosis.


Subject(s)
Drug Resistance, Bacterial/genetics , Mutation , Mycobacterium tuberculosis/drug effects , Mycobacterium tuberculosis/genetics , Pyrazinamide/pharmacology , Ribosomal Proteins/genetics , Humans , Microbial Sensitivity Tests , Molecular Dynamics Simulation , Protein Conformation, alpha-Helical , Ribosomal Proteins/chemistry
16.
J Chem Inf Model ; 59(7): 3229-3239, 2019 07 22.
Article in English | MEDLINE | ID: mdl-31244092

ABSTRACT

Juvenile myelomonocytic leukemia (JMML) is an invasive myeloproliferative neoplasm and is a childhood disease with very high clinical lethality. The SHP2 is encoded by the PTPN11 gene, which is a nonreceptor (pY)-phosphatase and mutation causes JMML. The structural hierarchy of SHP2 includes protein tyrosine phosphatase domain (PTP) and Src-homology 2 domain (N-SH2 and C-SH2). Somatic mutation (E76Q) in the interface of SH2-PTP domain is the most commonly identified mutation found in up to 35% of patients with JMML. The mechanism of this mutant associated with JMML is poorly understood. Here, molecular dynamics simulation was performed on wild-type and mutant (E76Q) of SHP2 to explore the precise impact of gain-of-function on PTP's activity. Consequently, such impact rescues the SHP2 protein from autoinhibition state through losing the interface interactions of Q256/F7 and S502/Q76 or weakening interactions of Q256/R4, Q510/G60, and Q506/A72 between N-SH2 and PTP domains. The consequences of these interactions further relieve the D'E loop away from the PTP catalytic site. The following study would provide a mechanistic insight for better understanding of how individual SHP2 mutations alter the PTP's activity at the atomic level.


Subject(s)
Gain of Function Mutation , Leukemia, Myelomonocytic, Juvenile/genetics , Molecular Dynamics Simulation , Protein Tyrosine Phosphatase, Non-Receptor Type 11/genetics , Amino Acid Sequence , Humans , Models, Molecular , Protein Conformation
17.
Bioorg Chem ; 92: 103284, 2019 11.
Article in English | MEDLINE | ID: mdl-31546207

ABSTRACT

New triazinoindole bearing thiazole/oxazole analogues (1-21) were synthesized and characterized through spectroscopic techniques such as HREI-MS, 1H and 13C NMR. The configuration of compound 2i and 2k was confirmed through NOESY. All analogues were evaluated against α-amylase inhibitory potential. Among the synthesized analogues, compound 1h, 1i, 1j, 2a and 2f having IC50 values 1.80 ±â€¯0.20, 1.90 ±â€¯0.30, 1.2 ±â€¯0.30, 1.2 ±â€¯0.01 and 1.30 ±â€¯0.20 µM respectively, showed excellent α-amylase inhibitory potential when compared with acarbose as standard (IC50 = 0.91 ±â€¯0.20 µM). All other analogues showed good to moderate inhibitory potential. Structural activity relationship (SAR) has been established and binding interactions were confirmed through docking studies.


Subject(s)
Glycoside Hydrolase Inhibitors/pharmacology , Molecular Docking Simulation , Oxazoles/pharmacology , Thiazoles/pharmacology , Triazines/pharmacology , alpha-Amylases/antagonists & inhibitors , Dose-Response Relationship, Drug , Glycoside Hydrolase Inhibitors/chemical synthesis , Glycoside Hydrolase Inhibitors/chemistry , Humans , Molecular Structure , Oxazoles/chemistry , Structure-Activity Relationship , Thiazoles/chemistry , Triazines/chemical synthesis , Triazines/chemistry , alpha-Amylases/metabolism
18.
Bioorg Chem ; 89: 103024, 2019 08.
Article in English | MEDLINE | ID: mdl-31176853

ABSTRACT

Despite of many diverse biological activities exhibited by benzimidazole scaffold, it is rarely explored for the urease inhibitory potential. For that purpose, benzimidazole analogues 1-19 were synthesized and screened for in vitro urease inhibitory potential. Structures of all synthetic analogues were deduced by different spectroscopic techniques. All analogues revealed inhibition potential with IC50 values of 0.90 ±â€¯0.01 to 35.20 ±â€¯1.10 µM, when compared with the standard thiourea (IC50 = 21.40 ±â€¯0.21 µM). Limited SAR suggested that the variations in the inhibitory potentials of the analogues are the result of different substitutions on phenyl ring. In order to rationalize the binding interactions of most active compounds with the active site of urease enzyme, molecular docking study was conducted.


Subject(s)
Benzimidazoles/pharmacology , Enzyme Inhibitors/pharmacology , Molecular Docking Simulation , Urease/antagonists & inhibitors , Benzimidazoles/chemical synthesis , Benzimidazoles/chemistry , Dose-Response Relationship, Drug , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Molecular Structure , Structure-Activity Relationship , Urease/metabolism
19.
Adv Exp Med Biol ; 1163: 335-357, 2019.
Article in English | MEDLINE | ID: mdl-31707710

ABSTRACT

The allosteric property of globular proteins is applauded as their intrinsic ability to regulate distant sites, and this property further plays a critical role in a wide variety of cellular regulatory mechanisms. Recent advancements and studies have revealed the manifestation of allostery in intrinsically disordered proteins or regions as allosteric sites present within or mediated by IDP/IDRs facilitates the signaling interactions for various biological mechanisms which would otherwise be impossible for globular proteins to regulate. This thematic review has highlighted the biological outcomes that can be achieved by the mechanism of allosteric regulation of intrinsically disordered proteins or regions. The similar mechanism has been implemented on Adenovirus 5 early region 1A and tumor apoptosis protein p53 in correspondence with other partners in binary and ternary complexes, which are the subject of the current review. Both these proteins regulate once they bind to their partners, consequently, forming either a binary or a ternary complex. Allosteric regulation by IDPs is currently a subject undergoing intense study, and the ongoing research work will ensure a better understanding of precision and efficiency of cellular regulation by them. Allosteric regulation mechanism can also be researched by intrinsically disordered protein-specific force field.


Subject(s)
Intrinsically Disordered Proteins , Allosteric Regulation , Intrinsically Disordered Proteins/chemistry , Protein Binding , Signal Transduction
20.
Bioorg Chem ; 65: 100-9, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26894559

ABSTRACT

Benzimidazole analogs 1-27 were synthesized, characterized by EI-MS and (1)HNMR and their α-glucosidase inhibitory activities were found out experimentally. Compound 25, 19, 10 and 20 have best inhibitory activities with IC50 values 5.30±0.10, 16.10±0.10, 25.36±0.14 and 29.75±0.19 respectively against α-glucosidase. Compound 6 and 12 has no inhibitory activity against α-glucosidase enzyme among the series. Further studies showed that the compounds are not showing any cytotoxicity effect. The docking studies of the compounds as well as the experimental activities of the compounds correlated well. From the molecular docking studies, it was observed that the top ranked conformation of all the compounds fit well in the active site of the homology model of α-glucosidase.


Subject(s)
Benzimidazoles/pharmacology , Glycoside Hydrolase Inhibitors/pharmacology , Glycoside Hydrolase Inhibitors/toxicity , Molecular Docking Simulation , alpha-Glucosidases/metabolism , 3T3-L1 Cells , Animals , Benzimidazoles/chemical synthesis , Benzimidazoles/chemistry , Cell Line , Dose-Response Relationship, Drug , Glycoside Hydrolase Inhibitors/chemical synthesis , Glycoside Hydrolase Inhibitors/chemistry , Mice , Molecular Structure , Rats , Rats, Wistar , Structure-Activity Relationship
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