Production of lysozyme and lysozyme-superoxide dismutase dimers bound by a ditryptophan cross-link in carbonate radical-treated lysozyme

Autor(es)

Paviani, Veronica ^[1] ; Queiroz, Raphael F. ^[2] ; Marques, Emerson F. ^[1] ; Di Mascio, Paolo ^[1] ; Augusto, Ohara ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim, Dept Bioquim, BR-05513970 Sao Paulo - Brazil

^[2] Univ Estadual Sudoeste Bahia, Dept Quim & Exatas, Salvador, BA - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Free Radical Biology and Medicine; v. 89, p. 72-82, DEC 2015.
• Citações Web of Science: 21

Resumo

Despite extensive investigation of the irreversible oxidations undergone by proteins in vitro and in vivo, the products formed from the oxidation of Trp residues remain incompletely understood. Recently, we characterized a ditryptophan cross-link produced by the recombination of hSOD1-tryptophanyl radicals generated from attack of the carbonate radical produced during the bicarbonate-dependent peroxidase activity of the enzyme. Here, we examine whether the ditryptophan cross-link is produced by the attack of the carbonate radical on proteins other than hSOD1. To this end, we treated hen egg white lysozyme with photolytically and enzymatically generated carbonate radical. The radical yields were estimated and the lysozyme modifications were analyzed by SDS-PAGE, western blot, enzymatic activity and MS/MS analysis. Lysozyme oxidation by both systems resulted in its inactivation and dimerization. Lysozyme treated with the photolytic system presented monomers oxidized to hydroxy-tryptophan at Trp(28) and Trp(123) and N-formylkynurenine at Trp(28), Trp(62) and Trp(123). Lysozyme treated with the enzymatic system rendered monomers oxidized to N-formylkynurenine at Trp28. The dimers were characterized as lysozyme-Trp(28)-Trp(28)-lysozyme and lysozyme-Trp(28)-Trp(32)-hSOD1. The results further demonstrate that the carbonate radical is prone to causing biomolecule cross-linking and hence, may be a relevant player in pathological mechanisms. The possibility of exploring the formation of ditryptophan cross-links as a carbonate radical biomarker is discussed. (C) 2015 Elsevier Inc. All rights reserved. (AU)

• Processo FAPESP: 08/57721-3 - Redoxoma
• Beneficiário: Ohara Augusto
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 13/07937-8 - Redoxoma
• Beneficiário: Ohara Augusto
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs