Characterization of Pharmaceutically Relevant Systems through Surface Plasmon Resonance and Circular Dichroism Spectroscopies

Studying biological interactions at a molecular level is crucial to rationally interpret pathophysiological conditions. Several analytical techniques have been engaged to elucidate different aspects of biological systems and, depending on the research question, medicinal chemists need to select the most tailored problem- solving approach. Among all possibilities, surface plasmon resonance (SPR) and circular dichroism (CD) spectroscopies offer intriguing potential. They can investigate both structural and functional aspects of biological targets and provide in return highly informative data output. In the present dissertation SPR and CD spectroscopies were employed to study different pharmaceutically relevant systems. The interaction between plant derivative Cucurbitacin, and serum albumins from different species (human and rat) was characterized with a combination of SPR direct binding assay and CD competition studies. Interestingly, two different binding profiles emerged. An extended SPR experimental set-up has been employed to investigate the interaction between the transcription factor from Helycobacter pylori NikR and the operator region of the urease promoter, revealing an isomerization of the protein–dsDNA complex occurring over time. SPR analysis was also employed to monitor the binding of Histone H4 residue to the methylation pocket of the epigenetic regulator SMYD3 in the presence of a selected small molecule (BCI-121). Results support in silico and in cellulo findings, confirming competition for the same binding site. CD detection was employed in combination with high performance liquid chromatography to achieve a full stereochemical characterization of Trans-3-(3,4- Dimethoxyphenyl)Glycidate enantiomers and to identify and quantify leva- and dexa-misole content in seized street cocaine samples. Studies reported in this dissertation highlighted how SPR and CD contribute to increase scientific knowledge on selected biological systems related to the field of life science. Moreover, assays developed here pose the basis for future inhibitors’ screening, which could eventually lead to the discovery of new chemical entities endowed with therapeutic properties.