o:25907 Antipsychotic clozapine binding to alpha-2-macroglobulin protects interacting partners against oxidation and preserves the anti-proteinase activity of the protein Vezivanje antipsihotika klozapina za alfa-2-makroglobulin štiti interagujuće partnere od oksidacije i čuva anti-proteaznu aktivnost proteina en ABSTRACT In this study, the interaction between clozapine, an atypical antipsychotic drug, and alpha-2-macroglobulin (α2M), a multipurpose anti-proteinase, was investigated under simulated (patho) physiological conditions using multiple spectroscopic techniques and molecular modeling. It was found that α2M binds clozapine with a moderate affinity (the binding constant of 0.9 × 10 5 M−1 at 37 °C). The preferable binding site for both clozapine's atropisomers was revealed to be a large pocket at the interface of C and D monomer subunits of the protein. Hydrogen bonds and the hydrophobic effect were proposed as dominant forces in complex formation. The binding of clozapine did not induce significant conformational change of the protein, as confirmed by virtually unaltered α2M secondary structure and anti-proteinase activity. However, both clozapine and α2M shielded each other from the deleterious influence of strong oxidants: sodium hypochlorite and 2,2′-azobis-2-methyl propanimidamide dihydrochloride (AAPH). Moreover, clozapine in a concentration range that is usually targeted in the plasma during patients' treatment effectively protected the anti-proteinase activity of α2M under AAPH-induced free radical overproduction. Our results suggest that the cooperation between α2M and clozapine may be a path by which these two molecules synergistically protect neural tissue against injury caused by disturbed proteostasis or oxidative stress. Sažetak alpha-2-macroglobulin, clozapine, protein-ligand interaction 1552099 10.1016/j.ijbiomac.2021.04.155 2022-06-03T14:23:18.223Z 44 yes 46 Miloš Šunderić University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia doktor biohemijskih nauka 0000-0002-0940-9481 Nikola Gligorijević University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia doktor biohemijskih nauka person 0000-0002-8691-2486 Milan R. Nikolić University of Belgrade, Faculty of Chemistry, Department of Biochemistry, Center of Excellence for Molecular Food Sciences, Serbia person Olgica Nedić University of Belgrade, Institute for the Application of Nuclear Energy INEP, Serbia doktor biohemijskih nauka person 0000-0003-2042-0056 Čedo Miljević University of Belgrade, Faculty of Medicine, Institute of Mental Health, Serbia person Miloš Milčić University of Belgrade, Faculty of Chemistry, Department of Biochemistry, Center of Excellence for Molecular Food Sciences, Serbia person Tamara Vasović University of Belgrade, Faculty of Chemistry, Department of Biochemistry, Center of Excellence for Molecular Food Sciences, Serbia person application/pdf 73618 https://phaidrabg.bg.ac.rs/o:25907 no yes 1 70 92000001 11A29 11A2905 11A19 11A1903 11A32 11A3278 International Journal of Biological Macromolecules 183 502 512 Elsevier 2021