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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Intra-dimer cooperativity between the active site cysteines during the oxidation of peroxiredoxin 2

Texto completo
Autor(es):
Peskin, Alexander V. [1] ; Meotti, Flavia C. [2] ; Souza, Luiz F. de [2] ; Anderson, Robert F. [3] ; Winterbourn, Christine C. [1] ; Salvador, Armindo [4, 5, 6, 7]
Número total de Autores: 6
Afiliação do(s) autor(es):
[1] Univ Otago Christchurch, Dept Pathol & Biomed Sci, Ctr Free Radical Res, Christchurch - New Zealand
[2] Univ Sao Paulo, Dept Biochem, Chem Inst, Sao Paulo, SP - Brazil
[3] Univ Auckland, Sch Chem Sci, Auckland - New Zealand
[4] Univ Coimbra, Coimbra - Portugal
[5] Univ Coimbra, CNC Ctr Neurosci Cell Biol, Coimbra - Portugal
[6] CQC, Dept Chem, Coimbra - Portugal
[7] Univ Coimbra, Inst Interdisciplinary Res, Coimbra - Portugal
Número total de Afiliações: 7
Tipo de documento: Artigo Científico
Fonte: Free Radical Biology and Medicine; v. 158, p. 115-125, OCT 2020.
Citações Web of Science: 0
Resumo

Peroxiredoxin 2 (Prdx2) and other typical 2-Cys Prdxs function as homodimers in which hydrogen peroxide oxidizes each active site cysteine to a sulfenic acid which then condenses with the resolving cysteine on the alternate chain. Previous kinetic studies have considered both sites as equally reactive. Here we have studied Prdx2 using a combination of non-reducing SDS-PAGE to separate reduced monomers and dimers with one and two disulfide bonds, and stopped flow analysis of tryptophan fluorescence, to investigate whether there is co-operativity between the sites. We have observed positive cooperativity when H2O2 is added as a bolus and oxidation of the second site occurs while the first site is present as a sulfenic acid. Modelling of this reaction showed that the second site reacts 2.2 +/- 0.1 times faster. In contrast, when H2O2 was generated slowly and the first active site condensed to a disulfide before the second site reacted, no cooperativity was evident. Conversion of the sulfenic acid to the disulfide showed negative cooperativity, with modelling of the exponential rise in tryptophan fluorescence yielding a rate constant of 0.75 +/- 0.08 s(-1) when the alternate active site was present as a sulfenic acid and 2.29 +/- 0.08-fold lower when it was a disulfide. No difference in the rate of hyperoxidation at the two sites was detected. Our findings imply that oxidation of one active site affects the conformation of the second site and influences which intermediate forms of the protein are favored under different cellular conditions. (AU)

Processo FAPESP: 13/07937-8 - Redoxoma
Beneficiário:Ohara Augusto
Linha de fomento: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
Processo FAPESP: 18/14898-2 - Processos redox na inflamação e o seu papel sobre doenças inflamatórias
Beneficiário:Flavia Carla Meotti
Linha de fomento: Auxílio à Pesquisa - Apoio a Jovens Pesquisadores - Fase 2
Processo FAPESP: 17/12312-8 - Papel das peroxirredoxinas na diferenciação de células leucêmicas de origem mielóide e na função dos neutrófilos
Beneficiário:Luiz Felipe de Souza
Linha de fomento: Bolsas no Brasil - Pós-Doutorado