Studies on the interactions of Ti-containing polyoxometalates (POMs) with SARS-CoV 3CLpro by molecular modeling

Synthesis and anti-HIV-1 activity evaluation of Keggin-type polyoxometalates with amino acid as organic cations

Polyoxometalates (POMs), as a class of multinuclear metal oxygen clusters, have promising biological activities. And their amino acid derivatives will lead to better pharmacological activity by the diversity in structures and properties. With reference to the anti-HIV-1 activities of PM-19 (K7PTi2W10O40) and its pyridinium derivatives, a series of novel Keggin-type POMs with amino acid as organic cations (A7PTi2W10O40) were synthesized by hydrothermal synthetic method. The final products were characterized by 1H NMR, Elemental analyzes and single crystal X-ray diffraction. All the synthesized compounds were obtained in the yields of 44.3-61.7% and evaluated the cytotoxicity and anti-HIV-1 activity in vitro. Compared with the reference compound PM-19, the target compounds had a lower toxicity to TZM-bl cells and a higher inhibitory activity against HIV-1. Among them, compound A3 showed higher anti-HIV-1 activity with IC50 of 0.11 nM than that of PM-19 with 4.68 nM. This study demonstrated that combination of Keggin-type POMs and amino acids can be a new strategy to enhance the anti-HIV-1 biological activity of POMs. All results will be expected to helpful for developing more potent and effective HIV-1 inhibitors.

Computational Modelling of the Interactions Between Polyoxometalates and Biological Systems

Polyoxometalates (POMs) structures have raised considerable interest for the last years in their application to biological processes and medicine. Within this area, our mini-review shows that computational modelling is an emerging tool, which can play an important role in understanding the interaction of POMs with biological systems and the mechanisms responsible of their activity, otherwise difficult to achieve experimentally. During recent years, computational studies have mainly focused on the analysis of POM binding to proteins and other systems such as lipid bilayers and nucleic acids, and on the characterization of reaction mechanisms of POMs acting as artificial metalloproteases and phosphoesterases. From early docking studies locating binding sites, molecular dynamics (MD) simulations have allowed to characterize the nature of POM···protein interactions, and to evaluate the effect of the charge, size, and shape of the POM on protein affinity, including also, the atomistic description of chaotropic character of POM anions. Although these studies rely on the interaction with proteins and nucleic acid models, the results could be extrapolated to other biomolecules such as carbohydrates, triglycerides, steroids, terpenes, etc. Combining MD simulations with quantum mechanics/molecular mechanics (QM/MM) methods and DFT calculations on cluster models, computational studies are starting to shed light on the factors governing the activity and selectivity for the hydrolysis of peptide and phosphoester bonds catalysed by POMs.

Can polyoxometalates (POMs) prevent of coronavirus 2019-nCoV cell entry? Interaction of POMs with TMPRSS2 and spike receptor domain complexed with ACE2 (ACE2-RBD): Virtual screening approaches

The unexpected appearance and global spread of COVID-19 create significant difficulties for healthcare systems and present an unusual challenge for the fast discovery of medicines to combat this fatal disease. Screening metallodrugs libraries from the medicinal inorganic chemistry society may expand the studied ‘chemical space’ and improve the probability of discovering effective anti-COVID drugs, including polyoxometalates. POMs are an oxygen-rich family of inorganic cluster systems that have previously been tested for antiviral action against different types of viruses. Human angiotensin-converting enzyme 2 (ACE2), human transmembrane protease serine 2 (TMPRSS2), and the SARS-CoV-2 spike glycoprotein are required for host cell-mediated viral entrance. Targeting these proteins demonstrates potential possibilities for preventing infections and transmissions in the initial stage. As a result, POMs with known antiviral effects were investigated for this purpose using molecular docking and dynamic simulations. This research shows that POMs can prevent SARS CoV-2 from entering cells by blocking TMPRSS2, which SARS-CoV-2 uses for spike glycoprotein priming. They may also engage with ACE2 and the spike glycoprotein and disrupt their binding by blocking the active sites. We think that a thorough investigation of POMs as possible anti-COVID-19 drugs will provide significant opportunities.

Human coronaviruses and therapeutic drug discovery

Background

Coronaviruses (CoVs) are distributed worldwide and have various susceptible hosts; CoVs infecting humans are called human coronaviruses (HCoVs). Although HCoV-specific drugs are still lacking, many potent targets for drug discovery are being explored, and many vigorously designed clinical trials are being carried out in an orderly manner. The aim of this review was to gain a comprehensive understanding of the current status of drug development against HCoVs, particularly severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Main text

A scoping review was conducted by electronically searching research studies, reviews, and clinical trials in PubMed and the CNKI. Studies on HCoVs and therapeutic drug discovery published between January 2000 and October 2020 and in English or Chinese were included, and the information was summarized. Of the 3248 studies identified, 159 publication were finally included. Advances in drug development against HCoV, especially SARS-CoV-2, are summarized under three categories: antiviral drugs aimed at inhibiting the HCoV proliferation process, drugs acting on the host's immune system, and drugs derived from plants with potent activity. Furthermore, clinical trials of drugs targeting SARS-CoV-2 are summarized.

Conclusions

During the spread of COVID-19 outbreak, great efforts have been made in therapeutic drug discovery against the virus, although the pharmacological effects and adverse reactions of some drugs under study are still unclear. However, well-designed high-quality studies are needed to further study the effectiveness and safety of these potential drugs so as to provide valid recommendations for better control of the COVID-19 pandemic.

An Androsterone-H2 @C60 hybrid: Synthesis, Properties and Molecular Docking Simulations with SARS-Cov-2

We report the synthesis and characterization of a fullerene‐steroid hybrid that contains H₂@C₆₀ and a dehydroepiandrosterone moiety synthesized by a cyclopropanation reaction with 76 % yield. Theoretical calculations at the DFT‐D3(BJ)/PBE 6‐311G(d,p) level predict the most stable conformation and that the saturation of a double bond is the main factor causing the upfield shielding of the signal appearing at −3.13 ppm, which corresponds to the H₂ located inside the fullerene cage. Relevant stereoelectronic parameters were also investigated and reinforce the idea that electronic interactions must be considered to develop studies on chemical‐biological interactions. A molecular docking simulation predicted that the binding energy values for the protease‐hybrid complexes were −9.9 kcal/mol and −13.5 kcal/mol for PL^pro and 3CL^pro respectively, indicating the potential use of the synthesized steroid‐H₂@C₆₀ as anti‐SARS‐Cov‐2 agent.

Preparation of polyoxometalate-doped aminosilane-modified silicate hybrid as a new barrier of chem-bio toxicant

Nanohybrid membranes based on the Keggin-type polyoxometalate (POM) H5PV2Mo10O40 and aminosilane-modified silicate (Ormosil and Ormosil(NR4+Cl-)) hybrids were synthesized as a new barrier to protect against simulants of chemical and biological toxicant. The 31P NMR and XPS results indicated that POM was bound to the Ormosil and Ormosil(NR4+Cl-) hybrids after impregnation. The antibacterial effects of the hybrids and hybrid-impregnated fabrics against Gram-negative and Gram-positive bacteria were investigated with zone of inhibition, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and plate-counting method. The MIC/MBC values of Ormosil(NR4+Cl-)/POM and Ormosil/POM against bacteria were 0.267/2.67 and 2.67/26.7, respectively, and the percentage reduction of bacteria was approximately 100% after 20 laundry cycles of their fabrics. The reaction products and mechanisms of the adsorptive degradation of 2-chloroethylethylsulfide (CEES) by hybrids were investigated with 13C NMR. The results of this study showed that POM-doped Ormosil systems are capable of destroying bacteria and CEES.

Inhibition of Human Immunodeficiency Virus Type 1 Entry by a Keggin Polyoxometalate

Here, we report the anti-human immunodeficiency virus (HIV) potency and underlying mechanisms of a Keggin polyoxometalate (PT-1, K₆HPTi₂W₁₀O₄₀). Our findings showed that PT-1 exhibited highly potent effects against a diverse group of HIV type 1 (HIV-1) strains and displayed low cytotoxicity and genotoxicity. The time-addition assay revealed that PT-1 acted at an early stage of infection, and these findings were supported by the observation that PT-1 had more potency against Env-pseudotyped virus than vesicular stomatitis virus glycoprotein (VSVG) pseudotyped virus. Surface plasmon resonance binding assays and flow cytometry analysis showed that PT-1 blocked the gp120 binding site in the CD4 receptor. Moreover, PT-1 bound directly to gp41 NHR (N36 peptide), thereby interrupting the core bundle formation of gp41. In conclusion, our data suggested that PT-1 may be developed as a new anti-HIV-1 agent through its effects on entry inhibition.

A survey of the different roles of polyoxometalates in their interaction with amino acids, peptides and proteins

This perspective provides a comprehensive description of the different roles of POMs in their interaction with relevant biological molecules.

Assembly of three stable POM-based pillar-layer CuI coordination polymers with visible light driven photocatalytic properties

Three new 3D POM-based Cu^I coordination polymers have been successfully prepared by a hydrothermal reaction. Compounds 1–3 show remarkably high heat stability, acid and alkali resistance, and effectively degrade methylene blue within visible light range.

Molecular simulation study of the binding mechanism of [α-PTi2W10O40]7- for its promising broad-spectrum inhibitory activity to FluV-A neuraminidase

Polyoxometalate (POM) has promising antiviral activities. It shows broad-spectrum inhibiting ability, high efficiency, and low toxicity. Experimental assays show that titanium containing polyoxotungstates have anti-influenza-virus activity. In this paper, the binding mechanisms of five isomers of di-Ti-substituted polyoxotungstate, [α-1,2-PTi₂W₁₀O₄₀]^7- (α-1,2), [α-1,6-PTi₂W₁₀O₄₀]^7- (α-1,6), [α-1,5-PTi₂W₁₀O₄₀]^7- (α-1,5), [α-1,4-PTi₂W₁₀O₄₀]^7- (α-1,4) and [α-1,11-PTi₂W₁₀O₄₀]^7- (α-1,11), to five subtypes of influenza virus A neuraminidase (FluV-A NA) were investigated in the context of aqueous solution by using molecular docking and molecular dynamics studies. The results show that the isomer α-1,2 is superior to other isomers as a potential inhibitor to neuraminidase. The positively charged arginine residues around the active site of NA could be induced by negatively charged POM to adapt themselves and could form salt bridge interactions and hydrogen bond interactions with POM. The binding free energies of POM/NA complexes range from -5.36 to -8.31 kcal mol^-1. The electrostatic interactions are found to be the driving force during the binding process of POM to NA. The conformational analysis shows that POM tends to bind primarily with N1 and N8 at the edge of the active pocket, which causes the conformational change of the pincers structure comprising residue 347 and loop 150. Whereas, the active pockets of N2, N9 and N4 are found to be more spacious, which allows POM to enter into the active pockets directly and anchor there firmly. This study shows that negatively charged ligand as POM could induce the reorganization of the active site of NA and highlights POM as a promising inhibitor to NA despite the ever increasing mutants of NA.

Electronic Supplementary Material

Supplementary material is available for this article at 10.1007/s11434-010-3271-8 and is accessible for authorized users.

Preparation and characterization of polyoxometalate-modified poly(vinyl alcohol)/polyethyleneimine hybrids as a chemical and biological self-detoxifying material

Nanohybrid membranes based on the Keggin-type polyoxometalate (POM) H5PV2Mo10O40 and a poly(vinyl alcohol)/polyethyleneimine (PVA/PEI) blend were prepared as a chemical and biological protective material. The objective of the study was to develop and evaluate permeable membranes (PVA/PEI) impregnated with reactive nanoparticulates (POM) that can protect against simulants of chemical and biological warfare agents. The physical properties of the PVA/PEI-POM hybrids were examined using SEM, TEM, TGA, and UV-Vis spectroscopy, the results of which indicated that the POM was incorporated in the PVA/PEI matrix after impregnation. The redox properties against 2-chloroethyl-ethyl sulfide (CEES) were investigated based on significant color changes and UV absorption in the POM upon reduction by CEES. The antibacterial effects of the PVA/PEI-POM hybrids were assessed by the zone of inhibition, minimum inhibitory concentration (MIC), and plate-counting methods. The results of this study showed that PVA/PEI-POM hybrids that act against simulants of chemical and biological weapons while retaining their ability to transmit moisture vapor could be obtained.

Preparation and antibacterial efficacy of bamboo charcoal/polyoxometalate biological protective material

Nanocomposites based on Keggin-type polyoxometalate H₅PV₂Mo₁₀O₄₀ (POM) and porous bamboo charcoal (BC) were prepared by activation and immobilization processes. The physical properties of the BC/POM composites were examined using FTIR, UV-Vis spectroscope, ³¹P MAS-NMR, SEM and TEM. These techniques indicated that the POM was intact on the surface of the BC matrix after impregnation. The POM particle size was found to be less than 150 nm based on TEM. The antibacterial effects of the BC/POM composites were assessed from the zone of inhibition, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and plate-counting method, and an excellent antibacterial performance was discovered.

Identification of polyoxometalates as nanomolar noncompetitive inhibitors of protein kinase CK2

Protein kinase CK2 is a multifunctional kinase of medical importance that is dysregulated in many cancers. In this study, polyoxometalates were identified as original CK2 inhibitors. [P2Mo18O62](6-) has the most potent activity. It inhibits the kinase in the nanomolar range by targeting key structural elements located outside the ATP- and peptide substrate-binding sites. Several polyoxometalate derivatives exhibit strong inhibitory efficiency, with IC50 values < or = 10 nM. Furthermore, these inorganic compounds show a striking specificity for CK2 when tested in a panel of 29 kinases. Therefore, polyoxometalates are effective CK2 inhibitors in terms of both efficiency and selectivity and represent nonclassical kinase inhibitors that interact with CK2 in a unique way. This binding mode may provide an exploitable mechanism for developing potent drugs with desirable properties, such as enhanced selectivity relative to ATP-mimetic inhibitors.