Tosaporn Sattasathuchana, Ph.D.
Abstarct
Quantum mechanics (QM) is a valuable tool for investigating chemical and biological phenomena at the molecular level. Two topics from my research group will be presented in this talk. The first topic focuses on our new hybrid QM-statistical mechanics approach, namely protein-ligand QM-VM2 (PLQM-VM2), for accurately predicting protein-ligand binding free energy. An accurate predictive capability is critical for enabling the virtual screening of drug candidate efficacy, which helps reduce time and cost in experimental drug development. Conceptually, the VeraChem mining minima (VM2) is employed for conformational sampling, and those ensemble conformers will be further refined by a QM approach to correct the binding free energies. Comparing with the molecular mechanics VM2 method, the PLQM-VM2 offers improvements in terms of rank order and parametric linear correlation with experimentally determined binding affinities. Due to the direct comparable energy scale of PLQM-VM2 for three diverse protein-ligand test systems, this motivates a further development in multiprotein screening capability to check for off-target activity of ligand series. The second topic in this talk is to gain a better understanding of the isovalency concept, specifically for silicon–nitrogen heterocyclic molecules. Si-substituted hydrocarbons have gained increasing attention due to their unique chemical bonding and electronic structure compared to their isovalent carbon counterparts. However, experimental findings reveal that the low-lying structure of pyridine has no hydrogen bonded with nitrogen, whereas the isomer containing N-H bond is the stable form of its Si-containing analog. To gain a deeper understanding of structure–stability relationships in silicon–nitrogen heterocycles, we performed a quasi- atomic orbital analysis.
When: September 12, 2025
Where: North Classroom 1130
Time: 11:00 am - 12:00pm