Quantum mechanical study on the activation mechanism of human carbonic anhydrase VII cluster model with bis-histamine schiff bases and bis-spinaceamine derivatives

Synthesis of Fused sp3-Enriched Imidazoles

A synthetic approach to imidazoles annulated to saturated six-membered cycles featuring S, SO2, NH, NCbz was developed. It was achieved by combining the Neber rearrangement and the Marckwald reaction. The Neber rearrangement applied to cyclic ketones allowed us to prepare in hundred gram quantities previously unknown α-amino ketones. Unstable tosyl ketoximes were used without purification immediately after their preparation. α-Amino ketones react with potassium thiocyanate and cyanate in almost a quantitative yield affording highly pure imidazol-2-thiones or imidazol-2-ones. Desulfurization of imidazole-2-thiones using Raney nickel led to the formation of previously unknown 2-unsubstituted fused imidazoles in high yields.

Predicting Carbonic Anhydrase Binding Affinity: Insights from QM Cluster Models

A systematic series of QM cluster models has been developed to predict the trend in the carbonic anhydrase binding affinity of a structurally diverse dataset of ligands. Reference DLPNO-CCSD(T)/CBS binding energies were generated for a cluster model and used to evaluate the performance of contemporary density functional theory methods, including Grimme's "3c" DFT composite methods (r2SCAN-3c and ωB97X-3c). It is demonstrated that when validated QM methods are used, the predictive power of the cluster models improves systematically with the size of the cluster models. This provided valuable insights into the key interactions that need to be modeled quantum mechanically and could inform how the QM region should be defined in hybrid quantum mechanics/molecular mechanics (QM/MM) models. The use of r2SCAN-3c on the largest cluster model composed of 16 residues appears to be an economical approach to predicting binding trends compared with using more robust DFT methods such as ωB97M-V and provides a significant improvement compared with docking.

Resveratrol Analogues as Dual Inhibitors of Monoamine Oxidase B and Carbonic Anhydrase VII: A New Multi-Target Combination for Neurodegenerative Diseases?

Neurodegenerative diseases (NDs) are described as multifactorial and progressive syndromes with compromised cognitive and behavioral functions. The multi-target-directed ligand (MTDL) strategy is a promising paradigm in drug discovery, potentially leading to new opportunities to manage such complex diseases. Here, we studied the dual ability of a set of resveratrol (RSV) analogs to inhibit two important targets involved in neurodegeneration. The stilbenols 1−9 were tested as inhibitors of the human monoamine oxidases (MAOs) and carbonic anhydrases (CAs). The studied compounds displayed moderate to excellent in vitro enzyme inhibitory activity against both enzymes at micromolar/nanomolar concentrations. Among them, the best compound 4 displayed potent and selective inhibition against the MAO-B isoform (IC50 MAO-A 0.43 µM vs. IC50 MAO-B 0.01 µM) with respect to the parent compound resveratrol (IC50 MAO-A 13.5 µM vs. IC50 MAO-B > 100 µM). It also demonstrated a selective inhibition activity against hCA VII (KI 0.7 µM vs. KI 4.3 µM for RSV). To evaluate the plausible binding mode of 1−9 within the two enzymes, molecular docking and dynamics studies were performed, revealing specific and significant interactions in the active sites of both targets. The new compounds are of pharmacological interest in view of their considerably reduced toxicity previously observed, their physicochemical and pharmacokinetic profiles, and their dual inhibitory ability. Compound 4 is noteworthy as a promising lead in the development of MAO and CA inhibitors with therapeutic potential in neuroprotection.

Feasible Cluster Model Method for Simulating the Redox Potentials of Laccase CueO and Its Variant

Laccases are regarded as versatile green biocatalysts, and recent scientific research has focused on improving their redox potential for broader industrial and environmental applications. The density functional theory (DFT) quantum mechanics approach, sufficiently rigorous and efficient for the calculation of electronic structures, is conducted to better comprehend the connection between the redox potential and the atomic structural feature of laccases. According to the crystal structure of wild type laccase CueO and its variant, a truncated miniature cluster model method was established in this research. On the basic of thermodynamic cycle, the overall Gibbs free energy variations before and after the one-electron reduction were calculated. It turned out that the trends of redox potentials to increase after variant predicted by the theoretical calculations correlated well with those obtained by experiments, thereby validating the feasibility of this cluster model method for simulating the redox potentials of laccases.

Amine- and Amino Acid-Based Compounds as Carbonic Anhydrase Activators

After being rather neglected as a research field in the past, carbonic anhydrase activators (CAAs) were undoubtedly demonstrated to be useful in diverse pharmaceutical and industrial applications. They also improved the knowledge of the requirements to selectively interact with a CA isoform over the others and confirmed the catalytic mechanism of this class of compounds. Amino acid and amine derivatives were the most explored in in vitro, in vivo and crystallographic studies as CAAs. Most of them were able to activate human or non-human CA isoforms in the nanomolar range, being proposed as therapeutic and industrial tools. Some isoforms are better activated by amino acids than amines derivatives and the stereochemistry may exert a role. Finally, non-human CAs have been very recently tested for activation studies, paving the way to innovative industrial and environmental applications.