Photoinduced damage to proteoliposomes by lipophilic photosensitizeromedical interest

ARDILA PADILLA, CARLOS A.; DANTOLA, MARIA LAURA; HERLAX, VANESA; VIGNONI, MARIANA

Campinas, San Pablo

Congreso; 47 th Annual Meeting of the Brazilian Biophysical Society; 2023

Brazilian Biophysical Society

Many natural heterocyclic compounds such as pterins, flavins, porphyrins can act asphotosensitizers (Sens), which are able of absorbing radiation in a region of theelectromagnetic spectrum in which biomolecules (lipids, DNA, proteins). In this type ofprocesses, excited states of the Sens are responsible for initiating the damage (1),leading to protein oxidation, oligomerization, fragmentation, and covalent adductformation (2,3). Lipid photosensitization results in peroxidation and increasedmembrane permeability (4,5). Since the reactions that occur in solution are notnecessarily replicated in vivo, the main objective of this work is to investigate thechemical, functional, and structural changes that occur in proteins and membranelipids due to photoinduced processes using proteoliposomes (PLs) as a biomimeticmodel. A lipophilic sensitizer will be added to PLs to obtain photoproteoliposomes(PPL). For the formation of PPLs, large unilamelar vesicles (LUVs) of phospholipidswith unsaturated fatty acid are formed by the extrusion method. Tyrosinase (TYR), anenzyme that catalyzes in mammals the first and rate-limiting step in the biosynthesisof the melanin, was used as a model protein; The Sens used was 3-decyl-riboflavin(decyl-Rf), which was previously synthesized, characterized, and evaluated as a Senscapable of binding to lipid membranes. Photolysis experiments were performed at pH7,4 with visible light (445 nm). Protein damage is assessed by measuring TYRenzymatic activity with a spectrophotometric technique, by measure the generation ofdopachroma (475 nm).This work was supported by Agencia Nacional de Promoción Científica y Tecnológica(ANPCyT-Grants PICT 2019-3416 and 2020-3103), Universidad Nacional de La Plata(UNLP-Grant X840) and Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET, PUE 2017-22920170100100CO).References1)Baptista, M.,et. al.PhotochemPhotobiol, 2017, 93, 912-919.2) Reid O., et. al.Biochemistry, 2020, 59,44, 4213.3)Dántola L.,et. al.Chem. Res. Toxicol., 2019, 32, 2250-2259.4) Vignoni A., et. al. DyesPigm., 2021 ,187, 109131 , 1 -10.5) Bacellar I., et.al. JACS.2018, 140, 30, 9606-9615