Impact of yohimbine on myoglobin stability: insights from molecular spectroscopic, and computational approaches

The prolific role of bioactive ligands in interacting with a variety of proteins has become a focal point of interest in pharmacokinetics and pharmacodynamics, thus sparking substantial enthusiasm within the realm of medicinal chemistry. The reversible binding of small molecules and proteins is a characteristic feature, and it's essential to investigate these interactions to understand their mode and mechanism of action within the human body. Therefore, the primary objective of the present study is to understand the underlying mechanism by which yohimbine (Yoh) interacts with protein myoglobin (Mb), employing both in silico and in vitro methodologies. The emission spectroscopy studies yielded a binding constant of 10⁵ M^-1 and a binding site ratio of 1:1. The structural perturbation induced in the protein Mb by Yoh was also illustrated by circular dichroism. The results of the molecular docking investigation resulted in numerous significant interactions between Mb and Yoh, indicating a substantial binding affinity. The accuracy of the docking data was further confirmed through the use of molecular dynamics (MD) simulations, which were then followed by principal component analysis and free energy landscape investigations. The study posited that the stability of the Mb-Yoh complex remains intact throughout the simulated duration, exhibiting little alterations in its structural conformation. Therefore, the association between ligand-protein plays a key role in determining circulatory lifetimes and bioavailability. These factors, in turn, are pivotal in the rational drug design process.