ELECTRONIC STUDY OF REACTIVITY OF THE SUBSTITUTED 8-HYDROXYQUINOLINE TO THE BIND SITE OF THE β-AMYLOID PEPTIDE TO ZINC ION

In this work, density functional theory (DFT) was used to study the caused effect on reactivity of 8-hydroxyquinoline (8-HQ) by substituent groups (-H, -CH3, -OCH3, -Cl and -NO2) on different positions of the 8-HQ structure. DFT was also used to obtain the electronic profile of β-amyloid peptide (Aβ) bind site to Zinc. The energies and absolute hardness (η) values, besides participation percentages values and graphical representation of highest occupied molecular orbital (HOMO) of 8-HQ derivatives and lowest unoccupied molecular orbital (LUMO) of Aβ bind site to Zinc (ZnAβ) were analysed. The calculations indicated that the hardest ligands with each substituent formed the most stable complexes with Zinc, and the electronic nature of substituent points to a preferential position on 8-HQ structure. The LUMO profile of ZnAβ showed that the ligands dislocate one of histidine residues for interacting with Zinc.