scholarly journals Discovery of Selective Inhibitor Leads by Targeting an Allosteric Site in Insulin-Regulated Aminopeptidase

2021 ◽  
Vol 14 (6) ◽  
pp. 584
Author(s):  
Ioannis Temponeras ◽  
Lykourgos Chiniadis ◽  
Athanasios Papakyriakou ◽  
Efstratios Stratikos
Keyword(s):  
Free Energy Calculations ◽  
Allosteric Site ◽  
In Vitro Evaluation ◽  
Terminal Domain ◽  
Zinc Database ◽  
Promising Target ◽  
Immune System Regulation ◽  
Dynamics Simulations ◽  
Selection Of

Insulin-Regulated aminopeptidase (IRAP) is a zinc-dependent aminopeptidase with several important biological functions and is an emerging pharmaceutical target for cognitive enhancement and immune system regulation. Aiming to discover lead-like IRAP inhibitors with enhanced selectivity versus homologous enzymes, we targeted an allosteric site at the C-terminal domain pocket of IRAP. We compiled a library of 2.5 million commercially available compounds from the ZINC database, and performed molecular docking at the target pocket of IRAP and the corresponding pocket of the homologous endoplasmic reticulum aminopeptidase 1 (ERAP1). Of the top compounds that showed high selectivity, 305 were further analyzed by molecular dynamics simulations and free energy calculations, leading to the selection of 33 compounds for in vitro evaluation. Two orthogonal functional assays were employed: one using a small fluorogenic substrate and one following the degradation of oxytocin, a natural peptidic substrate of IRAP. In vitro evaluation suggested that several of the compounds tested can inhibit IRAP, but the inhibition profile was dependent on substrate size, consistent with the allosteric nature of the targeted site. Overall, our results describe several novel leads as IRAP inhibitors and suggest that the C-terminal domain pocket of IRAP is a promising target for developing highly selective IRAP inhibitors.

The Research of New Inhibitors of Bacterial Methionine Aminopeptidase by Structure Based Virtual Screening Approach of ZINC DATABASE and In Vitro Validation

2020 ◽  
Vol 16 (4) ◽  
pp. 389-401 ◽  
Author(s):  
Hanane Boucherit ◽  
Abdelouahab Chikhi ◽  
Abderrahmane Bensegueni ◽  
Amina Merzoug ◽  
Jean-Michel Bolla
Keyword(s):  
Virtual Screening ◽  
Bacterial Survival ◽  
Methionine Aminopeptidase ◽  
Bacterial Strains ◽  
Microdilution Method ◽  
Zinc Database ◽  
Promising Target ◽  
New Antibiotics ◽  
Potential Inhibitors

Background: The great emergence of multi-resistant bacterial strains and the low renewal of antibiotics molecules are leading human and veterinary medicine to certain therapeutic impasses. Therefore, there is an urgent need to find new therapeutic alternatives including new molecules in the current treatments of infectious diseases. Methionine aminopeptidase (MetAP) is a promising target for developing new antibiotics because it is essential for bacterial survival. Objective: To screen for potential MetAP inhibitors by in silico virtual screening of the ZINC database and evaluate the best potential lead molecules by in vitro studies. Methods: We have considered 200,000 compounds from the ZINC database for virtual screening with FlexX software to identify potential inhibitors against bacterial MetAP. Nine chemical compounds of the top hits predicted were purchased and evaluated in vitro. The antimicrobial activity of each inhibitor of MetAP was tested by the disc-diffusion assay against one Gram-positive (Staphylococcus aureus) and two Gram-negative (Escherichia coli & Pseudomonas aeruginosa) bacteria. Among the studied compounds, compounds ZINC04785369 and ZINC03307916 showed promising antibacterial activity. To further characterize their efficacy, the minimum inhibitory concentration was determined for each compound by the microdilution method which showed significant results. Results: These results suggest compounds ZINC04785369 and ZINC03307916 as promising molecules for developing MetAP inhibitors. Conclusion: Furthermore, they could therefore serve as lead molecules for further chemical modifications to obtain clinically useful antibacterial agents.

scholarly journals Computational Perspectives into Plasmepsins Structure—Function Relationship: Implications to Inhibitors Design

2011 ◽  
Vol 2011 ◽  
pp. 1-15 ◽  
Author(s):  
Alejandro Gil L. ◽  
Pedro A. Valiente ◽  
Pedro G. Pascutti ◽  
Tirso Pons
Keyword(s):  
Structure Function ◽  
Free Energy Calculations ◽  
Special Focus ◽  
Binding Modes ◽  
Linear Interaction ◽  
Lead Compounds ◽  
Structure Function Relationship ◽  
Function Relationship ◽  
Dynamics Simulations ◽  
Selection Of

The development of efficient and selective antimalariais remains a challenge for the pharmaceutical industry. The aspartic proteases plasmepsins, whose inhibition leads to parasite death, are classified as targets for the design of potent drugs. Combinatorial synthesis is currently being used to generate inhibitor libraries for these enzymes, and together with computational methodologies have been demonstrated capable for the selection of lead compounds. The high structural flexibility of plasmepsins, revealed by their X-ray structures and molecular dynamics simulations, made even more complicated the prediction of putative binding modes, and therefore, the use of common computational tools, like docking and free-energy calculations. In this review, we revised the computational strategies utilized so far, for the structure-function relationship studies concerning the plasmepsin family, with special focus on the recent advances in the improvement of the linear interaction estimation (LIE) method, which is one of the most successful methodologies in the evaluation of plasmepsin-inhibitor binding affinity.

scholarly journals Structural Insight into the Binding of Cyanovirin-N with the Spike Glycoprotein, Mpro and PLpro of SARS-CoV-2: Protein–Protein Interactions, Dynamics Simulations and Free Energy Calculations

Molecules ◽  
2021 ◽  
Vol 26 (17) ◽  
pp. 5114
Author(s):  
Devashan Naidoo ◽  
Pallab Kar ◽  
Ayan Roy ◽  
Taurai Mutanda ◽  
Joseph Bwapwa ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Free Energy Calculations ◽  
Binding Potential ◽  
Global Public Health ◽  
Protein Protein Interactions ◽  
In Vivo Experiments ◽  
Poisson Boltzmann ◽  
Dynamics Simulations

The emergence of COVID-19 continues to pose severe threats to global public health. The pandemic has infected over 171 million people and claimed more than 3.5 million lives to date. We investigated the binding potential of antiviral cyanobacterial proteins including cyanovirin-N, scytovirin and phycocyanin with fundamental proteins involved in attachment and replication of SARS-CoV-2. Cyanovirin-N displayed the highest binding energy scores (−16.8 ± 0.02 kcal/mol, −12.3 ± 0.03 kcal/mol and −13.4 ± 0.02 kcal/mol, respectively) with the spike protein, the main protease (Mpro) and the papainlike protease (PLpro) of SARS-CoV-2. Cyanovirin-N was observed to interact with the crucial residues involved in the attachment of the human ACE2 receptor. Analysis of the binding affinities calculated employing the molecular mechanics-Poisson–Boltzmann surface area (MM-PBSA) approach revealed that all forms of energy, except the polar solvation energy, favourably contributed to the interactions of cyanovirin-N with the viral proteins. With particular emphasis on cyanovirin-N, the current work presents evidence for the potential inhibition of SARS-CoV-2 by cyanobacterial proteins, and offers the opportunity for in vitro and in vivo experiments to deploy the cyanobacterial proteins as valuable therapeutics against COVID-19.

scholarly journals Molecular dynamics simulations of nucleotide release from the circadian clock protein KaiC reveal atomic-resolution functional insights

2018 ◽  
Vol 115 (49) ◽  
pp. E11475-E11484 ◽  
Author(s):  
Lu Hong ◽  
Bodhi P. Vani ◽  
Erik H. Thiede ◽  
Michael J. Rust ◽  
Aaron R. Dinner
Keyword(s):  
Molecular Dynamics ◽  
Conformational Changes ◽  
Bound States ◽  
Large Scale ◽  
Nucleotide Exchange ◽  
Terminal Domain ◽  
Nucleotide Exchange Factor ◽  
Nucleotide Release ◽  
Dynamics Simulations

The cyanobacterial clock proteins KaiA, KaiB, and KaiC form a powerful system to study the biophysical basis of circadian rhythms, because an in vitro mixture of the three proteins is sufficient to generate a robust ∼24-h rhythm in the phosphorylation of KaiC. The nucleotide-bound states of KaiC critically affect both KaiB binding to the N-terminal domain (CI) and the phosphotransfer reactions that (de)phosphorylate the KaiC C-terminal domain (CII). However, the nucleotide exchange pathways associated with transitions among these states are poorly understood. In this study, we integrate recent advances in molecular dynamics methods to elucidate the structure and energetics of the pathway for Mg·ADP release from the CII domain. We find that nucleotide release is coupled to large-scale conformational changes in the KaiC hexamer. Solvating the nucleotide requires widening the subunit interface leading to the active site, which is linked to extension of the A-loop, a structure implicated in KaiA binding. These results provide a molecular hypothesis for how KaiA acts as a nucleotide exchange factor. In turn, structural parallels between the CI and CII domains suggest a mechanism for allosteric coupling between the domains. We relate our results to structures observed for other hexameric ATPases, which perform diverse functions.

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