Discovery of phosphonate derivatives containing different substituted 1,2,3-triazole motif as promising tobacco mosaic virus (TMV) helicase inhibitors for controlling plant viral diseases

BACKGROUND

The discovery and identification of targets is of far-reaching significance for developing novel pesticide candidates and increasing the probability of success. To explore and identify highly effective tobacco mosaic virus (TMV) helicase-targeted lead structures, a series of novel phosphonate derivatives containing a 1,2,3-triazole motif were rationally engineered and their antiviral activity was assessed.

RESULTS

Bioassay results showed that the optimized B17 exhibited more potent curative activity (EC50  = 271.5 μg mL-1 ) against TMV in vivo, which was superior to that of commercial Ribavirin (EC50  = 689.3 μg mL-1 ). B17 presented a stronger binding capacity through binding analysis with helicase, affording a corresponding value of 12.7 μM. Enzyme activity assay showed B17 exhibited excellent inhibitory activity on TMV helicase (39.2% at 300 μM). Furthermore, molecular docking simulations demonstrated that B17 displayed strong hydrogen-bond interactions (2.1, 2.1, 2.2, and 3.2 Å) with Ala-33, Gly-10, Gly-8, and Glu-217 of TMV helicase. Encouragingly, transmission electron microscopy analysis revealed that B17 could remarkably disrupt surface morphology and inhibit TMV proliferation. Additionally, these compounds also displayed potential anti-CMV (cucumber mosaic virus) and antipathogens (Xanthomonas oryzae pv. oryzae and Xanthomonas axonopodis pv. citri) by expanding their applications in agriculture.

CONCLUSION

Current research demonstrated that B17 could be considered as a potential antiviral agent alternative though targeting TMV helicase. © 2023 Society of Chemical Industry.

Aptamers for Viral Detection and Inhibition

Recent times have experienced more than ever the impact of viral infections in humans. Viral infections are known to cause diseases not only in humans but also in plants and animals. Here, we have compiled the literature review of aptamers selected and used for detection and inhibition of viral infections in all three categories: humans, animals, and plants. This review gives an in-depth introduction to aptamers, different types of aptamer selection (SELEX) methodologies, the benefits of using aptamers over commonly used antibody-based strategies, and the structural and functional mechanism of aptasensors for viral detection and therapy. The review is organized based on the different characterization and read-out tools used to detect virus-aptasensor interactions with a detailed index of existing virus-targeting aptamers. Along with addressing recent developments, we also discuss a way forward with aptamers for DNA nanotechnology-based detection and treatment of viral diseases. Overall, this review will serve as a comprehensive resource for aptamer-based strategies in viral diagnostics and treatment.

Design, Synthesis, and Mechanism of Antiviral Acylurea Derivatives Containing a Trifluoromethylpyridine Moiety

Novel acylurea derivatives 7a-7ab were designed and synthesized by linking the active substructures trifluoromethylpyridine and anthranilic diamide via an acylurea bridge. Most of the title compounds exhibited good activity against tobacco mosaic virus (TMV), particularly compound 7x (EC₅₀ of 211.8 μg/mL), which showed much higher curative activity than ningnanmycin (EC₅₀ of 389.8 μg/mL), and compound 7ab, which showed excellent inactivation activity (EC₅₀ of 36.1 μg/mL), similar to ningnanmycin (EC₅₀ of 23.2 μg/mL). The preliminary mechanism of these derivatives was investigated. Autodocking analysis revealed that compounds 7x and 7ab had good affinity for TMV coat protein (TMV CP), with low binding energies (-7.86 and -8.59 kcal/mol) comparable to ningnanmycin (-8.75 kcal/mol). Molecular dynamics simulation showed that compound 7x had a stable system structure with a better binding free energy (-32.94 kcal/mol) than ningnanmycin (-25.62 kcal/mol). Microscale thermophoresis showed that compound 7x bound more strongly to TMV CP (K_d of 19.8 ± 7.3 μM) than ningnanmycin (K_d of 21.2 ± 7.3 μM). Transmission electron microscopy and self-assembly experiments demonstrated that compounds 7x and 7ab significantly obstructed the self-assembly of TMV RNA and TMV CP. This new acylurea derivative has excellent antiviral activity by targeting TMV CP and inhibiting TMV self-assembly and can be considered a candidate for antiviral applications.

Prospects in the use of aptamers for characterizing the structure and stability of bioactive proteins and peptides in food

Food-derived bioactive proteins and peptides have gained acceptance among researchers, food manufacturers and consumers as health-enhancing functional food components that also serve as natural alternatives for disease prevention and/or management. Bioactivity in food proteins and peptides is determined by their conformations and binding characteristics, which in turn depend on their primary and secondary structures. To maintain their bioactivities, the molecular integrity of bioactive peptides must remain intact, and this warrants the study of peptide form and structure, ideally with robust, highly specific and sensitive techniques. Short single-stranded nucleic acids (i.e. aptamers) are known to have high affinity for cognate targets such as proteins and peptides. Aptamers can be produced cost-effectively and chemically derivatized to increase their stability and shelf life. Their improved binding characteristics and minimal modification of the target molecular signature suggests their suitability for real-time detection of conformational changes in both proteins and peptides. This review discusses the developmental progress of systematic evolution of ligands by exponential enrichment (SELEX), an iterative technology for generating cost-effective aptamers with low dissociation constants (K _d) for monitoring the form and structure of bioactive proteins and peptides. The review also presents case studies of this technique in monitoring the structural stability of bioactive peptide formulations to encourage applications in functional foods. The challenges and potential of aptamers in this research field are also discussed. Graphical abstract Advancing bioactive proteins and peptide functionality via aptameric ligands.

Peptide aptamers: The versatile role of specific protein function inhibitors in plant biotechnology

In recent years, peptide aptamers have emerged as novel molecular tools that have attracted the attention of researchers in various fields of basic and applied science, ranging from medicine to analytical chemistry. These artificial short peptides are able to specifically bind, track, and inhibit a given target molecule with high affinity, even molecules with poor immunogenicity or high toxicity, and represent a remarkable alternative to antibodies in many different applications. Their use is on the rise, driven mainly by the medical and pharmaceutical sector. Here we discuss the enormous potential of peptide aptamers in both basic and applied aspects of plant biotechnology and food safety. The different peptide aptamer selection methods available both in vivo and in vitro are introduced, and the most important possible applications in plant biotechnology are illustrated. In particular, we discuss the generation of broad-based virus resistance in crops, "reverse genetics" and aptasensors in bioassays for detecting contaminations in food and feed. Furthermore, we suggest an alternative to the transfer of peptide aptamers into plant cells via genetic transformation, based on the use of cell-penetrating peptides that overcome the limits imposed by both crop transformation and Genetically Modified Organism commercialization.