Showing papers in "Journal of Biomolecular Structure & Dynamics in 2018"
TL;DR: Based on thermodynamic, spectroscopic and computational observations it can be concluded that HSA-riboflavin complex is mainly stabilized by various non-covalent forces with binding energy of −7.2 kcal mol−1.
Abstract: Riboflavin (RF) plays an important role in various metabolic redox reactions in the form of flavin adenine dinucleotide and flavin mononucleotide. Human serum albumin (HSA) is an important protein ...
80 citations
TL;DR: The interactions between estradiol and two carrier proteins in aqueous solution at pH = 7.4 were studied by three-dimensional fluorescence emission spectroscopy, isothermal titration calorimetry (ITC), zeta-potential, resonance light-scattering and molecular modeling.
Abstract: The interactions between estradiol and two carrier proteins, ie human serum albumin (HSA) and holo-transferrin (HTF) in aqueous solution at pH = 74 were studied by three-dimensional fluorescence emission spectroscopy, isothermal titration calorimetry (ITC), zeta-potential, resonance light-scattering and molecular modeling Extensive fluorescence quenching was observed throughout the interaction between the drug and both proteins Moreover, conformational changes were determined by observing the rearrangement of Trp residues during binding of estradiol with HSA and HTF at different concentrations ITC experiments revealed that, in the presence of estradiol, both van der Waals forces and hydrogen bonding became predominant In addition, other binding parameters such as enthalpy and entropy changes were determined by the zeta potential method Molecular modeling suggested that estradiol was situated within sub-domain IB sited in the hydrophobic cluster in Site I, whereas the drug was located in the N-terminal of HTF where it was hydrogen bonded with Ala 670
78 citations
TL;DR: All of the NSAIDs exhibited potential activity against Aβ fibrils in terms of predicted binding affinity, and Sulindac was found to be the most active compound underscoring the contribution of indene methylene substitution, whereas acetaminophen was observed as least active NSAID.
Abstract: Aggregation of amyloid beta (Aβ) protein considered as one of contributors in development of Alzheimer’s disease (AD) Several investigations have identified the importance of non-steroidal anti-in
77 citations
TL;DR: It is concluded that ZINC2111081 has a great potential to inhibit MtbICL and would add to the drug discovery process against tuberculosis.
Abstract: Mycobacterium tuberculosis is the etiological agent of tuberculosis in humans and is responsible for more than two million deaths annually. M. tuberculosis isocitrate lyase (MtbICL) catalyzes the first step in the glyoxylate cycle, plays a pivotal role in the persistence of M. tuberculosis, which acts as a potential target for an anti-tubercular drug. To identify the potential anti-tuberculosis compound, we conducted a structure-based virtual screening of natural compounds from the ZINC database (n = 1,67,748) against the MtbICL structure. The ligands were docked against MtbICL in three sequential docking modes that resulted in 340 ligands having better docking score. These compounds were evaluated for Lipinski and ADMET prediction, and 27 compounds were found to fit well with re-docking studies. After refinement by molecular docking and drug-likeness analyses, three potential inhibitors (ZINC1306071, ZINC2111081, and ZINC2134917) were identified. These three ligands and the reference compounds were furth...
65 citations
TL;DR: This study has identified ZINC01155930 ((4R)-3-(cycloheptoxycarbonyl)-4-(4-etochromen-3-yl)-2-methyl-4,6,7,8-tetrahydroquinolin-5-olate) as a suitable efflux pump inhibitor worthy of further investigation in order to be used for controlling infections caused by Acinetobacter baumannii.
Abstract: Emergence of multi-drug resistant strains of Acinetobacter baumannii has caused significant health problems and is responsible for high morbidity and mortality. Overexpression of AdeABC efflux syst...
62 citations
TL;DR: Once temsirolimus binds to HSA, it changes conformation of HSA which in turn can alter the functionality of this important carrier protein and this altered functionality of H SA can be highlighted in variety of diseases.
Abstract: The binding interaction between temsirolimus, an important antirenal cancer drug, and HSA, an important carrier protein was scrutinized making use of UV and fluorescence spectroscopy. Hyper chromat...
60 citations
TL;DR: This in silico ‘per-residue energy decomposition pharmacophore’ virtual screening approach will be critical in aiding scientists in the discovery of not only effective inhibitors of Zika viral targets, but also a wide range of anti-viral agents.
Abstract: The re-emerging Zika virus (ZIKV) is an arthropod-borne virus that has been described to have explosive potential as a worldwide pandemic. The initial transmission of the virus was through a mosquito vector, however, evolving modes of transmission has allowed the spread of the disease over continents. The virus has already been linked to irreversible chronic central nervous system conditions. The concerns of the scientific and clinical community are the consequences of Zika viral mutations, thus suggesting the urgent need for viral inhibitors. There have been large strides in vaccine development against the virus but there are still no FDA approved drugs available. Rapid rational drug design and discovery research is fundamental in the production of potent inhibitors against the virus that will not just mask the virus, but destroy it completely. In silico drug design allows for this prompt screening of potential leads, thus decreasing the consumption of precious time and resources. This study demonstrates an optimized and proven screening technique in the discovery of two potential small molecule inhibitors of ZIKV Methyltransferase and RNA dependent RNA polymerase. This in silico 'per-residue energy decomposition pharmacophore' virtual screening approach will be critical in aiding scientists in the discovery of not only effective inhibitors of Zika viral targets, but also a wide range of anti-viral agents.
56 citations
TL;DR: Results are extremely relevant that the chemical modification of Graphene nanosheet using covalent functionalization scheme is an effectual approach for loading and delivery of Tegafur drug molecule within biological systems.
Abstract: In the present work, we apply comprehensive theoretical calculations in order to study Tegafur drug adsorption on the nanostructured functionalized Graphene with hydroxyl, epoxide, carbonyl, and carboxyl groups in the water environment. The physical nature of Tegafur adsorption offers advantages in terms of easy desorption of anticancer molecule with no structural or electronic change of the adsorbed drug. By functionalization of Graphene nanosheet with a carbonyl group, a considerable increase on the binding energy between Tegafur drug and the nanosheet is noted. Diminish in energy gap with the adsorption of Tegafur drug on the functionalized nanosheets shows that the reactivity of functionalized complexes increases upon loading of the drug molecule. Besides, the adsorption process yields an increase of the polarity which causes the possibility of the solubility and dispersion of the considered complexes enhances. This result is indicative the suitability of the nanomaterials toward Tegafur drug delivery within the biological environments. The high solvation energy of Tegafur anticancer drug adsorbed functionalized Graphene models enforced their applicability as nanocarriers in the living system. These results are extremely relevant that the chemical modification of Graphene nanosheet using covalent functionalization scheme is an effectual approach for loading and delivery of Tegafur drug molecule within biological systems.
56 citations
TL;DR: A number of pyrazolo[3,4-d]pyrimidine PDE1 inhibitors were subjected to different molecular modelling techniques to get a detailed knowledge about the physicochemical and structural requirements for higher inhibitory activity.
Abstract: Phosphodiesterase 1 (PDE1) is a potential target for a number of neurodegenerative disorders such as Schizophrenia, Parkinson's and Alzheimer's diseases. A number of pyrazolo[3,4-d]pyrimidine PDE1 inhibitors were subjected to different molecular modelling techniques [such as regression-based quantitative structure-activity relationship (QSAR): multiple linear regression, support vector machine and artificial neural network; classification-based QSAR: Bayesian modelling and Recursive partitioning; Monte Carlo based QSAR; Open3DQSAR; pharmacophore mapping and molecular docking analyses] to get a detailed knowledge about the physicochemical and structural requirements for higher inhibitory activity. The planarity of the pyrimidinone ring plays an important role for PDE1 inhibition. The N-methylated function at the 5th position of the pyrazolo[3,4-d]pyrimidine core is required for interacting with the PDE1 enzyme. The cyclopentyl ring fused with the parent scaffold is necessary for PDE1 binding potency. The phenylamino substitution at 3rd position is crucial for PDE1 inhibition. The N2-substitution at the pyrazole moiety is important for PDE1 inhibition compared to the N1-substituted analogues. Moreover, the p-substituted benzyl side chain at N2-position helps to enhance the PDE1 inhibitory profile. Depending on these observations, some new molecules are predicted that may possess better PDE1 inhibition.
55 citations
TL;DR: A structure-based virtual screening of natural compounds from the ZINC database against the FgTrx1 structure found two compounds that could be potential drug candidates to fight against F. gigantica parasites.
Abstract: Fasciola gigantica is the causative organism of fascioliasis and is responsible for major economic losses in livestock production globally. F. gigantica thioredoxin1 (FgTrx1) is an important redox-...
51 citations
TL;DR: This study identified the potential COMT inhibitors through pharmacophore-based inhibitor screening leading to a more complete understanding of molecular-level interactions.
Abstract: Alzheimer's disease (AD) is one of the most significant neurodegenerative disorders and its symptoms mostly appear in aged people. Catechol-o-methyltransferase (COMT) is one of the known target enzymes responsible for AD. With the use of 23 known inhibitors of COMT, a query has been generated and validated by screening against the database of 1500 decoys to obtain the GH score and enrichment value. The crucial features of the known inhibitors were evaluated by the online ZINC Pharmer to identify new leads from a ZINC database. Five hundred hits were retrieved from ZINC Pharmer and by ADMET (absorption, distribution, metabolism, excretion, and toxicity) filtering by using FAF-Drug-3 and 36 molecules were considered for molecular docking. From the COMT inhibitors, opicapone, fenoldopam, and quercetin were selected, while ZINC63625100_413 ZINC39411941_412, ZINC63234426_254, ZINC63637968_451, and ZINC64019452_303 were chosen for the molecular dynamics simulation analysis having high binding affinity and structural recognition. This study identified the potential COMT inhibitors through pharmacophore-based inhibitor screening leading to a more complete understanding of molecular-level interactions.
TL;DR: The obtained results from spectroscopic and electrochemistry experiments along with the computational studies suggest that DZN binds to residues located in subdomains IIA of HSA with binding constant about 1410.9 M−1 at 300 K.
Abstract: In the present research, the binding properties of diazinon (DZN), as an organophosphorus herbicide, to human serum albumin (HSA) were investigated using combination of spectroscopic, electrochemis
TL;DR: The present approach showed a good performance in assessing the thermal stability of large amounts of DNA hairpins comprehensively and promising to improve the structure simulation by consummating basic databases.
Abstract: On the basis of high-resolution melting, a high-throughput approach to measure melting temperatures (Tms) of short DNA hairpins was developed. With this method, Tms of thousands of triloop, tetraloop, and pentaloop hairpins involving various loop sequences and various closing base pairs (cbp) were obtained in hours. The stability of triloop hairpins decreased with the change of cbp (5'-3') in the order of c-g > g-c > t-a ≥ a-t, showing that the cbp of 5'-Pyr-Pur-3' (Pyr = pyrimidine, Pur = purine) contributed more stability than 5'-Pur-Pyr-3'. For tetraloop hairpins, GNNA, GNAB, and CNNG (N = A, G, C, or T; B = G, C, or T) were found to be highly stable irrespective of the cbp type. TNNA was also stable in both g-c and a-t families, while CGNA only in the c-g family. Pentaloop hairpins of cTGNAGg, cGNYNAg (Y = T or C) and cCGNNAg were exceptionally stable motifs. In most cases, pyrimidine-rich loops were more favorable to stabilize the whole structure than purine-rich ones. The present approach showed a good performance in assessing the thermal stability of large amounts of DNA hairpins comprehensively. These data are useful to understand the sequence dependence of the stability of DNA secondary structures and promising to improve the structure simulation by consummating basic databases.
TL;DR: The results show that flavonols can convincingly bind to active site of MMP-9 as demonstrated by their stable interactions at the S1′ specificity pocket and favourable binding energies.
Abstract: Cartilage degradation in rheumatoid arthritis is mediated principally by the collagenases and gelatinases. Gelatinase B (also called matrix metalloproteinase 9 – MMP-9), is a valid target molecule ...
TL;DR: Screening of the characterized compounds by a resazurin microplate assay method revealed that ethyl group at second position of indolizine nucleus exhibited activity against susceptible and multidrug-resistant strains of Mycobacterium tuberculosis.
Abstract: A series of trisubstituted indolizine analogues has been designed as a result of a fragment-based approach to target the inhibition of mycobacterial enoyl-acyl carrier protein reductase. Anti-tuberculosis (TB) screening of the characterized compounds by a resazurin microplate assay method revealed that ethyl group at second position of indolizine nucleus exhibited activity against susceptible and multidrug-resistant strains of Mycobacterium tuberculosis at concentration of 5.5 and 11.3 μg/mL, respectively. A molecular docking study was also conducted to evaluate the stability of the active compounds, and compound with ethyl substitution at second position of indolizine nucleus showed the highest free binding energy of ΔG −24.11 (kcal/mol), a low clash score of 3.04, and high lipo score of −13.33. Indolizine analog with ethyl substitution at second position demonstrated Molecular Mechanics/Generalized Born Surface Area (−23.85 kcal/mol). Two molecular dynamics studies were computed (100 ps and 50 ns) to ca...
TL;DR: Genome-wide analysis of selected Arabidopsis MYB genes revealed their function in plant development and abiotic stress response, consistent with gene ontology annotations, and provide a useful framework for further experimental studies for the functional characterization of the target MyB genes in the context of regulation of phenylpropanoid biosynthesis and plant stress response.
Abstract: The MYB gene family represents one of the largest groups of transcription factors in plants. Recent evidences have also demonstrated key role of MYB transcription factors in regulating the expression of major genes involved in the biosynthesis of phenylpropanoid compounds which confer biotic and abiotic stress tolerance in plant species. However, no comprehensive genome-wide analysis of the phenylpropanoid pathway-associated MYB transcription factors has been reported thus far. In this study, 11 Arabidopsis MYB proteins, such as MYB3, MYB4, MYB7, MYB11, MYB12, MYB32, MYB75, MYB90, MYB111, MYB113, and MYB114 were initially identified considering their reported regulatory function in phenylpropanoid biosynthesis pathway. Subsequent genome-wide analysis have identified the corresponding homologues from Glycine max, Vigna radiata, Oryza sativa, and Zea mays, while homologous of Arabidopsis MYB75, MYB90, MYB113, and MYB114 were not detected in rice and maize genomes. The identified MYB proteins were classified into three groups (I-III) based on phylogeny. Sequence and domain analysis revealed presence of two conserved DNA binding MYB domains in the selected MYB proteins. Promoter analysis indicated presence of cis-regulatory elements related to light signaling, development, and stress response. Expression analysis of selected Arabidopsis MYB genes revealed their function in plant development and abiotic stress response, consistent with gene ontology annotations. Together, these results provide a useful framework for further experimental studies for the functional characterization of the target MYB genes in the context of regulation of phenylpropanoid biosynthesis and plant stress response.
TL;DR: The binding interactions of novel synthesized copper (II) complexes with bovine serum albumin (BSA) are endothermic driven by entropic factors as confirmed by high sensitivity isothermal titration calorimetry.
Abstract: Serum albumins being the most abundant proteins in the blood and cerebrospinal fluid are significant carriers of essential transition metal ions in the human body. Studies of copper (II) complexes ...
TL;DR: A structure-based virtual screening of natural compounds from the ZINC database against the OfCYP450 concluded that Zinc8790946, ZINC70707116, and ZINC85878789 have excellent potential to inhibit OfCyp450.
Abstract: Opisthorchis felineus is the etiological agent of opisthorchiasis in humans. O. felineus cytochrome P450 (OfCYP450) is an important enzyme in the parasite xenobiotic metabolism. To identify the pot...
TL;DR: It was deduced that drug resistance reversal potential of catharanthine was due to inhibition of the efflux pumps, which resulted in the identification of tripartite protein complexes (MexA, MexB, and OprM) as promising drug target for the screening of natural and synthetic inhibitors.
Abstract: Multidrug resistance (MDR) put an alarming situation like preantibiotic era which compels us to invigorate the basic science of anti-infective chemotherapy. Hence, the drug resistant genes/proteins were explored as promising drug targets. Keeping this thing in mind, proteome of Pseudomonas aeruginosa PA01 was explored, which resulted in the identification of tripartite protein complexes (MexA, MexB, and OprM) as promising drug target for the screening of natural and synthetic inhibitors. The purpose of present investigation was to explore the drug resistance reversal potential mechanism of catharanthine isolated from the leaves of Catharanthus roseous. Hence, the test compound catharanthine was in silico screened using docking studies against the above receptors, which showed significant binding affinity with these receptors. In order to validate the in silico findings, in vitro evaluation of the test compound was also carried out. In combination, catharanthine reduced the minimum inhibitory concentration MIC of tetracycline (TET) and streptomycin up to 16 and 8 folds, respectively. Further, in time kill assay, catharanthine in combination with TET reduced the cell viability in concentration dependent manner and was also able to reduce the mutation prevention concentration of TET. It was also deduced that drug resistance reversal potential of catharanthine was due to inhibition of the efflux pumps.
TL;DR: This study led to the identification of 10 potential compounds with good fitness, docking score, which make important interactions with the protein active site and concluded that the identified compounds may act as new leads for the design of Mtb MurG inhibitors.
Abstract: MurG (Rv2153c) is a key player in the biosynthesis of the peptidoglycan layer in Mycobacterium tuberculosis (Mtb) This work is an attempt to highlight the structural and functional relationship of Mtb MurG, the three-dimensional (3D) structure of protein was constructed by homology modelling using Discovery Studio 35 software The quality and consistency of generated model was assessed by PROCHECK, ProSA and ERRAT Later, the model was optimized by molecular dynamics (MD) simulations and the optimized model complex with substrate Uridine-diphosphate-N-acetylglucosamine (UD1) facilitated us to employ structure-based virtual screening approach to obtain new hits from Asinex database using energy-optimized pharmacophore modelling (e-pharmacophore) The pharmacophore model was validated using enrichment calculations, and finally, validated model was employed for high-throughput virtual screening and molecular docking to identify novel Mtb MurG inhibitors This study led to the identification of 10 potential
TL;DR: The interaction of Prussian blue nanoparticles with protein was investigated and it was found that the BSA intrinsic fluorescence was quenched upon addition of PBNPs due to the static interaction, suggesting the binding of PbnPs with BSA.
Abstract: Owning to their exceptional properties, Prussian blue nanoparticles (PBNPs) are promising in a variety of biomedical applications. In this scenario, understanding of how PBNPs interact and behave in biological systems is essential. Herein, the interaction of PBNPs with protein was investigated. Specifically, the citric acid stabilized PBNPs with a size of 10 nm were synthesized and characterized. The interactions of these PBNPs with the model protein, bovine serum albumin (BSA), were then probed by spectroscopic methods. It was found that the BSA intrinsic fluorescence was quenched upon addition of PBNPs due to the static interaction, suggesting the binding of PBNPs with BSA. Moreover, the synchronous fluorescence and circular dichroism spectra indicated the conformational change of BSA due to the presence of PBNPs.
TL;DR: The present study involves the finding of novel inhibitor based on the information of dimeric CCD of IN in complex with known inhibitor, which were carried out by applying a structure-based virtual screening concept with molecular docking to inhibit the interaction between IN and LEDGF/p75.
Abstract: HIV-1 integrase is a unique promising component of the viral replication cycle, catalyzing the integration of reverse transcribed viral cDNA into the host cell genome Generally, IN activity requires both viral as well as a cellular co-factor in the processing replication cycle Among them, the human lens epithelium-derived growth factor (LEDGF/p75) represented as promising cellular co-factor which supports the viral replication by tethering IN to the chromatin Due to its major importance in the early steps of HIV replication, the interaction between IN and LEDGF/p75 has become a pleasing target for anti-HIV drug discovery The present study involves the finding of novel inhibitor based on the information of dimeric CCD of IN in complex with known inhibitor, which were carried out by applying a structure-based virtual screening concept with molecular docking Additionally, Free binding energy, ADME properties, PAINS analysis, Density Functional Theory, and Enrichment Calculations were performed on selected compounds for getting a best lead molecule On the basis of these analyses, the current study proposes top 3 compounds: Enamine-Z742267384, Maybridge-HTS02400, and Specs-AE-848/37125099 with acceptable pharmacological properties and enhanced binding affinity to inhibit the interaction between IN and LEDGF/p75 Furthermore, Simulation studies were carried out on these molecules to expose their dynamics behavior and stability We expect that the findings obtained here could be future therapeutic agents and may provide an outline for the experimental studies to stimulate the innovative strategy for research community
TL;DR: Energy decomposition and hydrogen bond analysis demonstrate that residues Pro82, Leu92, Asn140, and Ile146 play important roles in binding processes of inhibitors to BRD4-1 and indicate that van der Waals interactions are main factors to modulate inhibitor bindings.
Abstract: In the current work, conformational changes of bromodomain-containing protein 4 (1) (BRD4-1) induced by bindings of inhibitors XD29 (57G), XD35 (57F), and XD28 (L28) were investigated using molecular dynamics (MD) simulations and principal component analysis. The results demonstrate that inhibitor bindings produce significant effect on the motion of ZA loop in BRD4-1. Moreover, to further study binding modes of three inhibitors to BRD4-1, binding free energies of inhibitors to BRD4-1 were also calculated using molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) method. The results indicate that van der Waals interactions are main factors to modulate inhibitor bindings. Energy decomposition and hydrogen bond analysis demonstrate that residues Pro82, Leu92, Asn140, and Ile146 play important roles in binding processes of inhibitors to BRD4-1. This study is not only helpful for better understanding function and internal dynamics of BRD4-1, but also can provide a theoretical basis for rational designs of effective anticancer drugs targeting BRD4-1.
TL;DR: The in vitro cytotoxicity of the complexes on two cancer cells lines showed that the compounds had broad spectrum, anti-cancer activity with low IC50 values and the order of in vitro anticancer activities is consistent with the DNA-binding affinities.
Abstract: [Pd{(C,N)–C6H4CH2NH(Et) (Qu)] (2) and [Pd{(C,N)–C6H4CH2NH(Et) (Nar)] (3) (Qu = Quercetin, Nar = Naringin) mononuclear palladium (II) complexes have been synthesized and characterized using elementa...
TL;DR: An insight into the binding of aceclofenac with bovine serum albumin at physiological condition: a spectroscopic and computational approach is provided.
Abstract: Bovine serum albumin (BSA) is one of the most abundant serum albumins in plasma. This class of protein plays a vital role in the transportation of a variety of exogenous and endogenous substances s...
TL;DR: The experiments indicate that this Co(II) complex could strongly bind to CT-DNA via minor groove mechanism and fluorescence spectrometry of BSA with the complex showed that the fluorescence quenching mechanism of B SA was of static type.
Abstract: [C20H17N3O2] and cobalt (II) complex [Co(L2)(MeOH)2].ClO4, (L2 = 4-((E)-1-((2-(((E)-pyridin-2-ylmethylene) amino) phenyl) imino) ethyl) benzene-1, 3-diol) novel Schiff base has been synthesiszed and chracterized by Fourier transform infrared, UV–vis, 1H-NMR spectroscopy, and elemental analysis techniques. The interaction of Co(II) complex with DNA and BSA was investigated by electronic absorption spectroscopy, fluorescence spectroscopy, circular dichroism, and thermal denaturation studies. Our experiments indicate that this complex could strongly bind to CT-DNA via minor groove mechanism. In addition, fluorescence spectrometry of BSA with the complex showed that the fluorescence quenching mechanism of BSA was of static type. The complex exhibited significant in vitro cytotoxicity against three human cancer cell lines (JURKAT, SKOV3, and U87). The molecular docking experiment effectively proved the binding of complex to DNA and BSA. Finally, antibacterial assay over gram-positive and gram-negative pathogen...
TL;DR: A large compound library containing 2,703,000 compounds retrieved from Otava database was screened against class I HDACs by exhaustive approach of structure-based virtual screening using rDOCK and Autodock Vina, and a total of 41 compounds were found to show high-isoform selectivity.
Abstract: Histone deacetylases (HDACs) have gained increased attention as targets for anticancer drug design and development. HDAC inhibitors have proven to be effective for reversing the malignant phenotype in HDAC-dependent cancer cases. However, lack of selectivity of the many HDAC inhibitors in clinical use and trials contributes to toxicities to healthy cells. It is believed that, the continued identification of isoform-selective inhibitors will eliminate these undesirable adverse effects – a task that remains a major challenge to HDAC inhibitor designs. Here, in an attempt to identify isoform-selective inhibitors, a large compound library containing 2,703,000 compounds retrieved from Otava database was screened against class I HDACs by exhaustive approach of structure-based virtual screening using rDOCK and Autodock Vina. A total of 41 compounds were found to show high-isoform selectivity and were further redocked into their respective targets using Autodock4. Thirty-six compounds showed remarkable isoform se...
TL;DR: ISO-induced alternation in the UV absorption, synchronous fluorescence and CD spectra in the absence and presence of the quencher indicates the complex formation and the esterase activity result suggests that ISO acts as competitive inhibitor.
Abstract: Isoprenaline hydrochloride is a potential cardiovascular drug helps in the smooth functioning of the heart muscles. So, we have performed the binding study of ISO with BSA. This study was investigated by UV absorption, fluorescence, synchronous fluorescence, circular dichroism, etc. The analysis of intrinsic fluorescence data showed the low binding affinity of ISO. The binding constant Kb was 2.8 × 103 M-1 and binding stoichiometry (n) was approximately one and the Gibb’s free energy change at 310 K was determined to be -8.69 kcal mol−1. Negative Gibb’s free energy change shows the spontaneity of the BSA and ISO interaction. We have found ISO-induced alternation in the UV absorption, synchronous fluorescence and CD spectra in the absence and presence of the quencher indicates the complex formation. In synchronous fluorescence, red shift was obtained because of the complex formation of BSA and ISO. The distance (r) between the BSA (donor) and ISO (acceptor) was 2.89 nm, determined by FRET. DLS measurements...
TL;DR: Comp comparable molecular dynamics simulations were performed to elucidate the inhibitory mechanism of a sulfonamide inhibitor C1, revealing that C1 inhibits Aβ42 aggregation by stabilizing native helical conformation and inhibiting the formation of aggregation-prone β-sheet conformation.
Abstract: Alzheimer's disease (AD) is a progressive neurodegenerative disorder that is characterized by loss of intellectual functioning of brain and memory loss. According to amyloid cascade hypothesis, aggregation of amyloid-β42 (Aβ42) peptide can generate toxic oligomers and their accumulation in the brain is responsible for the onset of AD. In spite of carrying out a large number of experimental studies on inhibition of Aβ42 aggregation by small molecules, the detailed inhibitory mechanism remains elusive. In the present study, comparable molecular dynamics (MD) simulations were performed to elucidate the inhibitory mechanism of a sulfonamide inhibitor C1 (2,5-dichloro-N-(4-piperidinophenyl)-3-thiophenesulfonamide), reported for its in vitro and in vivo anti-aggregation activity against Aβ42. MD simulations reveal that C1 stabilizes native α-helix conformation of Aβ42 by interacting with key residues in the central helix region (13-26) with hydrogen bonds and π-π interactions. C1 lowers the solvent-accessible surface area of the central hydrophobic core (CHC), KLVFF (16-20), that confirms burial of hydrophobic residues leading to the dominance of helical conformation in the CHC region. The binding free energy analysis with MM-PBSA demonstrates that Ala2, Phe4, Tyr10, Gln15, Lys16, Leu17, Val18, Phe19, Phe20, Glu22, and Met35 contribute maximum to binding free energy (-43.1 kcal/mol) between C1 and Aβ42 monomer. Overall, MD simulations reveal that C1 inhibits Aβ42 aggregation by stabilizing native helical conformation and inhibiting the formation of aggregation-prone β-sheet conformation. The present results will shed light on the underlying inhibitory mechanism of small molecules that show potential in vitro anti-aggregation activity against Aβ42.
TL;DR: Bovine serum albumin is a single-chain large globular protein consisting of 583 amino acid residues which contains three structurally homologous domains which are divided by 17...
Abstract: Bovine serum albumin (BSA) is a single-chain large globular protein consisting of 583 amino acid residues. It contains three structurally homologous domains (I, II, and III) which are divided by 17...