A mechanistic approach towards the formation of bityrosine in proteins by ionizing radiation-GYG model peptide

Autor(es)

Sowinski, Sebastian ^[1] ; Varca, Gustavo H. C. ^{[1, 2]} ; Kadlubowski, Slawomir ^[1] ; Lugao, Ademar B. ^[2] ; Ulanski, Piotr ^[1]

Afiliação do(s) autor(es)

^[1] Lodz Univ Technol, Fac Chem, Inst Appl Radiat Chem IARC, Wroblewskiego 15, PL-93590 Lodz - Poland

^[2] Inst Pesquisas Energet & Nucl IPEN CNEN SP, Av Prof Lineu Prestes 2242, Cidade Univ, BR-05508000 Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Radiation Physics and Chemistry; v. 188, NOV 2021.
• Citações Web of Science: 0

Resumo

One of the methods of protein crosslinking used in the synthesis of protein-based nanoparticles is the formation of bityrosine bridges, which may be achieved by the recombination of phenoxyl-type radicals in irradiated protein solutions. Radiation-induced formation of phenoxyl radicals in tyrosine is promoted in presence of H+. In this work, kinetics of this process and the influence of pH were studied by pulse radiolysis measurements of a model peptide H-Gly-Tyr-Gly-OH (GYG), which may help to solve questions raised for bigger, more complex systems in comparable conditions. The main route of phenoxyl radicals formation consists of the addition reaction of hydroxyl radical to the phenol ring on the tyrosine side-chain and proton catalyzed water molecule elimination. A similar effect was observed in studies of tripeptide solutions containing phosphate buffer. The presented data include time-resolved optical spectroscopy of transient species formed under pulse electron beam irradiation and a comparison of the kinetics of the phenoxyl radicals formation in samples at various pH and in presence of phosphate buffer. The postulated mechanism and obtained values of rate constants of the formation and decay of transient species were additionally checked by simple probabilistic simulations. (AU)

• Processo FAPESP: 10/10935-9 - Desenvolvimento de hidrogel nanoestruturado contendo complexo de papaína e ciclodextrina
• Beneficiário: Gustavo Henrique Costa Varca
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto