Biology subjects

D'Antonio, E. L.

Publications and source records attributed to D'Antonio, E. L..

2 recordsLinked to original sources

bioRxiv2026

Targeting Dengue Virus NS3 Helicase: Biochemical and Computational Evaluation of Catechins from Camellia sinensis as Potential Therapeutic Leads

Dengue virus serotype 2 is a human pathogenic flavivirus encoding non-structural protein 3 (DEN2-NS3), a superfamily-2 viral helicase. DEN2-NS3 contains an N-terminal protease domain and a C-terminal RNA helicase/nucleoside 5'-triphosphatase (NTPase) domain essential for replication. The enzyme utilizes energy from NTP hydrolysis to translocate 3'-to-5' along a duplex RNA substrate. Prompted by the high potency of (--)-epigallocatechin gallate (EGCG) against Zika virus, this study investigated if three catechins, EGCG, (--)-epicatechin gallate (ECG), and (--)-epigallocatechin (EGC), would be potent inhibitors of DEN2-NS3. Enzyme-inhibition assays demonstrated that the catalytic domain, DEN2-NS3(S171-K618), was strongly inhibited by the galloylated catechins (EGCG and ECG), verified by an enzyme-coupled confirmatory assay. Inhibition constants (Ki) and suggestive inhibition modes relative to NTPase activity were Ki = 400 {+/-} 86.6 nM for EGCG (mixed-mode), Ki = 550 {+/-} 250 nM for ECG (uncompetitive), and Ki = 18.3 {+/-} 4.2 {micro}M for EGC (mixed-mode). The coronavirus inhibitor SSYA10-001 inhibited DEN2-NS3 (Ki = 10.2 {+/-} 0.3 {micro}M, mixed-mode). Computational workflows using SiteMap identified a predicted druggable pocket associated with the RNA-binding region, involving residues ASP290, ARG387, ASP409, MET429, HIS487, ASP541, ARG599, and ASP603. Catechins were analyzed through 200-ns molecular dynamics simulations to evaluate binding stability. Computational results revealed that EGCG and ECG maintained high stability, forming highly persistent shared amino acid contacts (>45% occupancy) with ASP603, ARG599, ASP541, and ARG387. Biochemical and computational data support these galloylated catechin leads, suggesting a plausible binding model within an amphipathic pocket. Future structural optimization into stable prodrug derivatives could yield promising antiviral candidates.

biochemistry↗

bioRxiv2024

The Multifunctional Catalytic Hemoglobin from Amphitrite ornata: Protocols on Isolation, Taxonomic Identification, Protein Extraction, Purification, and Characterization

The multifunctional catalytic hemoglobin from the terebellid polychaete Amphitrite ornata, also named dehaloperoxidase (AoDHP), utilizes the typical oxygen transport function in addition to four observed activities involved in substrate oxidation. The multifunctional ability of AoDHP is presently a rare observation, and there exists a limitation for how novel dehaloperoxidases can be identified from macrobenthic infauna. In order to discover more infaunal DHP-bearing candidates, we have devised a facilitated method for an accurate taxonomic identification that places visual and molecular taxonomic approaches in parallel. Traditional visual taxonomic species identification by the non-specialist, at least for A. ornata, or even for other marine worms, is a very difficult and time-consuming task since a large diversity is present and the method is restricted to adult worm specimens. The work herein aimed to describe a method that particularly simplifies the taxonomic identification of A. ornata through the assessment of its mitochondrial cytochrome c oxidase subunit I gene by employing the DNA barcoding technique. Furthermore, whole worm specimens of A. ornata were used to extract and purify AoDHP followed by an H2O2-dependent peroxidase activity assay evaluation against substrate 2,4,6-trichlorophenol. AoDHP isoenzyme A was also overexpressed as the recombinant protein in Escherichia coli, and its peroxidase activity parameters were compared to AoDHP from the natural source. The activity assay assessment indicated a tight correlation for all Michaelis-Menten parameters evaluated. We conclude that the method described herein exhibits a streamlined approach to identify the polychaete A. ornata, which can be adopted by the non-specialist, and the full procedure is predicted to facilitate the discovery of novel dehaloperoxidases from other marine invertebrates.

biochemistry↗