Abstract
Human Ca(v)1.3 (hCa(v)1.3) is of great interest as a potential target for Parkinson's disease. However, common medications like dihydropyridines (DHPs), a kind of classic calcium channel blocker, have poor selectivity to hCa(v)1.3 in clinical treatment, mainly due to being implicated in cardiovascular side-effects mediated by human Ca(v)1.2 (hCa(v)1.2). Recently, pyrimidine-2,4,6-triones (PYTs) have received extensive attention as prominent selective inhibitors to hCa(v)1.3. In this study, we describe the selectivity mechanism of PYTs for hCa(v)1.2 and hCa(v)1.3 based on molecular dynamic simulation methods. Our results reveal that the van der Waals (vdW) interaction was the most important force affecting selectivity. Moreover, the hydrophobic interaction was more conducive to the combination. The highly hydrophobic amino acid residues on hCa(v)1.3, such as V162 (IR1), L303 (IR2), M481 (IR3), and F484 (IR3), provided the greatest contributions in the binding free energy. On the other hand, the substituents of a halogen-substituted aromatic ring, cycloalkyl and norbornyl on PYTs, which are pertinent to the steric hindrance of the compounds, played core roles in the selectivity and affinity for hCa(v)1.3, whereas strong polar substituents needed to be avoided. The findings could provide valuable information for designing more effective and safe medicines for Parkinson's disease.