Study of Short Peptide Adsorption on Solution Dispersed Inorganic Nanoparticles Using Depletion Method

Fundamentals of inorganic-organic interactions are critically important in the discovery and development of novel biointerfaces amenable for utilization ...

South Ural State University

In 1979, R.D.Cramer and M.Milne made a first realization of 3D comparison of molecules by aligning them in space and by mapping their molecular fields to a 3D grid. Further, this approach was developed as the DYLOMMS (Dynamic Lattice- Oriented Molecular Modelling System) approach. In 1984, H.Wold and S.Wold proposed the use of partial least squares (PLS) analysis, instead of principal component analysis, to correlate the field values with biological activities. Then, in 1988, the method which was called CoMFA (Comparative Molecular Field Analysis) was introduced and the appropriate software became commercially available. Since 1988, a lot of 3D QSAR methods, algorithms and their modifications are introduced for solving of virtual drug discovery problems (e.g., CoMSIA, CoMMA, HINT, HASL, GOLPE, GRID, PARM, Raptor, BiS, CiS, ConGO,). All the methods can be divided into two groups (classes):1. Methods studying the exterior of molecules; 2) Methods studying the interior of molecules.

Grid-based Continual Analysis of Molecular Interior for Drug Discovery, QSAR and QSPR.

Various techniques for rational drug design are presented in the paper. The methods are based on a substitution of antipharmacophore atoms of the molecules of training dataset by new atoms and/or group of atoms increasing the atomic bioactivity increments obtained from an SAR study. Furthermore, a design methodology based on the genetic algorithm DesPot for discrete optimization and generation of new drug candidate structures is described. Additionally, wide spectra of SAR approaches (3D/4D QSAR interior and exterior-based methods - BiS, CiS, ConGO, CoMIn, high-quality docking method - ReDock) using MERA force field and/or AlteQ quantum chemical method for correct prognosis of bioactivity and the bioactive probability have been described. The design methods are implemented at www.chemosophia.com web-site for online computational services.

Grid-Based Technologies for In Silico Screening and Drug Design.

Malaria, particularly in endemic countries remains a threat to the human health and is the leading the cause of mortality in the tropical and sub-tropical areas. Herein, we explored new C symmetric hydroxyethylamine analogs as the potential inhibitors of Plasmodium falciparum (P. falciparum; 3D7) in in-vitro cultures. All the listed compounds were also evaluated against crucial drug targets, plasmepsin II (Plm II) and IV (Plm IV), enzymes found in the digestive vacuole of the P. falciparum. Analog 10f showed inhibitory activities against both the enzymes Plm II and Plm IV (K, 1.93 ± 0.29 µM for Plm II; K, 1.99 ± 0.05 µM for Plm IV). Among all these analogs, compounds 10g selectively inhibited the activity of Plm IV (K, 0.84 ± 0.08 µM). In the in vitro screening assay, the growth inhibition of P. falciparum by both the analogs (IC, 2.27 ± 0.95 µM for 10f; IC, 3.11 ± 0.65 µM for 10g) displayed marked killing effect. A significant growth inhibition of the P. falciparum was displayed by analog 12c with IC value of 1.35 ± 0.85 µM, however, it did not show inhibitory activity against either Plms. The hemolytic assay suggested that the active compounds selectively inhibit the growth of the parasite. Further, potent analogs (10f and 12c) were evaluated for their cytotoxicity towards mammalian HepG2 and vero cells. The selectivity index (SI) values were noticed greater than 10 for both the analogs that suggested their poor toxicity. The present study indicates these analogs as putative lead structures and could serve as crucial for the development of new drug molecules.

Antiplasmodial activity of hydroxyethylamine analogs: Synthesis, biological activity and structure activity relationship of plasmepsin inhibitors.

A great step toward describing the structure of the molecular electron was made in the era of quantum chemical methods. Methods play a very important role in the prediction of molecular properties and in the description of the reactivity of compounds, which cannot be overestimated. There are many works, books, and articles on quantum methods, their applications, and comparisons. At the same time, quantum methods of a high level of theory, which give the most accurate results, are time-consuming, which makes them almost impossible to describe large complex molecular systems, such as macromolecules, enzymes, supramolecular compounds, crystal fragments, and so on.

Topological Analysis of Electron Density in Large Biomolecular Systems.

The review describes online resources used for drug discovery and design. Internet resources can be classified into two classes. The first class of resources accumulates information about drugs, drug candidates, compounds, and bioassays. This information is a starting point in drug discovery and design. It is necessary for a training dataset composition. The data found at this step are needed in the search for the rules predicting a biological activity or recognizing active compounds among other molecules. The following databases can be used: ChEMBL, different databases of US National Institutes of Health, DrugBank, PDBind-CN Database, RCSB Protein Data Bank (PDB), BRENDA, etc. The second class of Internet resources includes web-portals performing online computations for drug discovery and design. The web-portals perform: 1) modelling of molecular structure such as geometry optimization and molecular docking; 2) online computations of various descriptors, physical-chemical and ADMET properties influencing the bioprocesses occurring in a living organism along the road of the drug therapeutic action; 3) quantitative structure-activity relationship (QSAR) and quantitative structure-property relationship (QSPR) studies; 4) prognosis of bioactivities of compounds; 5) design of new drug candidates. These are, for example, ChemAxon, ACD/ I-lab, Mcule, OCHEM, eADMET, ChemoSophia, DockingServer, 1-click Docking, MDWeb, DockingServer, ZDOCK, etc. The role of docking online resources for modeling of "ligand-receptor" complexes, prognosis of bioactivities, and drug design is discussed. The review highlights the possibilities of Internet resources for a study of a drug action at the most important stages. A detailed assessment of the advantages of the reviewed Internet resources is done.

Internet Resources for Drug Discovery and Design.

The present research focused on designing a quinazoline skeleton, framed via 1,3,5-triazine derivatives (QBT) through field mapping and alignment studies. The QBT derivatives were synthesized via time- and cost-effective protocol. The 3D-QSAR study, computational physicochemical properties, and ADME calculation of the derivatives were performed to establish the affinity towards the biological system. Molecular docking in the adenosine triphosphate binding site of the RET tyrosine kinase domain (PDB ID: 7IVU) was studied to elucidate vital structural residues necessary for bioactivity. The derivatives were evaluated for anticancer potency against TPC-1 cells (thyroid cancer), MCF-7 cells (breast cancer), and one normal cell line (human foreskin fibroblasts) via 3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyltetrazolium bromide assay followed by an in ovo CAM assay. The entire series of derivatives (8a-o) showed mild to significant anticancer potency against the selected cancer cell lines.

Quinazoline based 1,3,5-triazine derivatives as cancer inhibitors by impeding the phosphorylated RET tyrosine kinase pathway: Design, synthesis, docking, and QSAR study.

The dormant  is evolved to develop the tolerance against the acidification of phagolysosome by the action of gamma interferon. The molecular mechanism responsible for the development of the resistance towards the acidic conditions in  is not fully understood. Therefore, the current analysis was performed which studies the mechanism of acid tolerance by correlating the alteration in the protonation state of conserved residues in virulent proteins with changes in their folding states. The pH dependencies of proteins were studied using an efficient computational scheme which enables the understanding of their conformational behavior by molecular dynamics (MD) simulations. The adopted methodology involves cyclically updating of the ionization states of titrable residues in the studied proteins with conventional MD steps, which were applied to the newly generated ionization configuration. Significant pH-dependent protein structural stability parameters consistent with the changes of the protonation states of conserved residues were observed. Among the studied proteins, the peptidoglycan binding protein ompATB, carboxylesterase LipF and two-component systems' transcriptional regulator PhoP showed highest structural conservation in the observed acidic pH range throughout the course of MD simulations. The current study provides a better understanding of acid tolerance mechanisms present in  and can facilitate the drug development strategies against the dormant protein targets.Communicated by Ramaswamy H. Sarma.

The structural basis of acid resistance in : insights from multiple pH regime molecular dynamics simulations.

Inflammation acts as an alarming signal for the progression of various biological complications. Various reports in the literature have revealed that heterocycle-containing synthetic compounds have a restorative capability against acute and chronic inflammatory stages. In the current study, we synthesized a series of 1,2,4-triazole-conjugated 1,3,4-thiadiazole hybrid scaffolds and evaluated their impacts against carrageenan-induced paw edema and proinflammatory markers in Wistar rats. Further, 3D QSAR study (three-dimensional quantitative structure-activity relationships), ADMET (absorption, distribution, metabolism, and excretion) profiling, and docking studies were performed to determine the possible mechanism of the action of the derivatives. The study shows that the most active derivatives, 13f and 13g, have optimal logP, a higher anti-inflammatory activity score, and poor metabolism at various sites of cytochrome P450. The docking studies recommended that the synthesized compounds have a similar affinity as the ligands A307, 63X, and S58 to interact with tumor necrosis factor-α, COX-1, and COX-2. So, these molecules will definitely hold a promise for the future drug development initiative.

1,2,4-Triazole-conjugated 1,3,4-thiadiazole hybrid scaffolds: A potent ameliorant of carrageenan-induced inflammation by lessening proinflammatory mediators.

The computational prediction of ligand-biopolymer affinities is a crucial endeavor in modern drug discovery and one that still poses major challenges. The choice of the appropriate computational method often reveals itself as a trade-off between accuracy and speed, with mathematical devices referred to as scoring functions being the fastest. Among the many shortcomings of scoring functions there is the lack of universal applicability to every molecular system. This is so largely due to their reliance on atom type perception and/or parametrization. This article proposes the use of nonparametric Model of Effective Radii of Atoms descriptors that can be readily computed for the entire Periodic Table and demonstrate that, in combination with machine learning algorithms, they can yield competitive performances and chemically meaningful insights.

Nonparametric chemical descriptors for the calculation of ligand-biopolymer affinities with machine-learning scoring functions.

In this letter the newly introduced approach based on the radial distribution function (RDF) weighted by the number of va-lence shell electrons is applied for a series of HIV-1 protease enzyme and its complexes with inhibitors to evaluate the influ-ence of hydrogen atoms on the performance of the model. The multiple linear regression method was used for the selection of the relevant descriptors. Two groups of residues having dominant contribution to the RDF descriptor are identified as relevant for the inhibition. In the first group are residues like Arg8, Asp25, Thr26, Gly27 and Asp29, which establish direct interaction with the inhibitor, while the second group consists of the amino acids at the interface of the two homodimer sub-units or with the solvent. The crucial motif pointed out by our approach as the most important for inhibition of the enzyme's activity and present in all inhibitors is hydroxyl group that establish hydrogen bond with Asp25 side chain. Additionally, the comparison to the model without hydrogen showed that both models are of similar quality, but the downside of the current model is the need for the determination of residues' protonation states.

The Influence of Hydrogen atoms on the Performance of Radial Distribution Function Based Descriptors in the Chemoinformatic Studies of HIV-1 Prote-ase Complexes with Inhibitors.

Vladimir Potemkin

Nanotechnology Education and Research Center,
Laboratory of Computational Modelling of Drugs

South Ural State University

Study of Short Peptide Adsorption on Solution Dispersed Inorganic Nanoparticles Using Depletion Method

Vladimir Potemkin

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Nanotechnology Education and Research Center,Laboratory of Computational Modelling of Drugs

South Ural State University

Study of Short Peptide Adsorption on Solution Dispersed Inorganic Nanoparticles Using Depletion Method

Nanotechnology Education and Research Center,
Laboratory of Computational Modelling of Drugs