Fluoroacetate dehalogenase (FAcD) is a unique, nonmetal-dependent enzyme capable of cleaving the inert C-F bond of fluoroacetate (FA) under mild conditions, making it an important enzymatic model for organofluorine degradation. This study investigated the catalytic degradation mechanism of FA by FAcD using density functional theory calculations with an active-site cluster model. The model included the FA substrate, two crystallographic water molecules, and the key amino acid residues surrounding the active site. An integrated energy profile connecting defluorination and hydrolysis was obtained within a single computational framework. The calculated reaction pathway consists of four elementary steps: (I) C-F bond activation, (II) nucleophilic attack, (III) C-O bond cleavage, and (IV) proton transfer. Structural analyses showed that Arg111, Arg114, and Tyr219 stabilize the carboxylate group of FA and His155, Trp156, and Tyr219 stabilize the fluoride anion during C-F bond cleavage. Furthermore, His155 was suggested to activate the hydrolytic water molecule and participate directly in the nucleophilic attack step. These findings provide a unified quantum-chemical description of FAcD-catalyzed defluorination and hydrolysis and offer insights into the design of engineered enzymes and biomimetic catalysts for organofluorine degradation.
Manussada Ratanasak, Yuta Hori, Kohei Sato et al.· Journal of Physical Chemistr...· 0 citations
DNA topoisomerase IIα (Topo IIα) is essential for maintaining genomic stability during DNA replication and mitosis and is highly expressed in cancer cells, making it a promising target for anticancer therapy. In this study, bis-thiourea derivatives were investigated for their Topo IIα inhibitory activity and anticancer potential using in silico and in vitro studies. Molecular modeling demonstrated that compound 8 exhibited favorable binding affinity and stability within the ATPase domain of Topo IIα. Biochemical assays revealed that compound 8 inhibited Topo IIα activity and showed potent cytotoxicity against several cancer cell lines, particularly A549 cells. Mechanistic studies showed that compound 8 inhibited A549 cell migration and invasion by upregulating E-cadherin while downregulating the mesenchymal markers N-cadherin and vimentin, as well as the EMT-associated transcription factor Slug. Furthermore, compound 8 induced G1-phase arrest by downregulating cyclins D1 and E2 while upregulating p21. These results suggest that compound 8 represents a promising lead for Topo IIα-targeted cancer therapy.
Results show that sequence changes outside the binding site can modulate ligand binding indirectly, and that the ligand interaction network is useful for evaluating edited aptamers.
Aamir Aman, Leonhard Sidl, Nitchakan Darai et al.· International Journal of Mol...· 0 citations
We use cookies to run the site and, with your consent, for analytics and to show ads.
See our Cookie Policy.
