Intermediate Tyrosyl Radical and Amyloid Structure in Peroxide-Activated Cytoglobin

Author(s):Show less -

Ferreira, Juliana C. ^[1] ; Marcondes, Marcelo F. ^[1] ; Icimoto, Marcelo Y. ^[1] ; Cardoso, Thyago H. S. ^[1] ; Tofanello, Aryane ^[2] ; Pessoto, Felipe S. ^[2] ; Miranda, Erica G. A. ^[2] ; Prieto, Tatiana ^{[2, 3]} ; Nascimento, Otaciro R. ^[3] ; Oliveira, Vitor ^[1] ; Nantes, Iseli L. ^{[1, 2]}

Affiliation

^[1] Univ Fed Sao Paulo, Dept Bioquim, Sao Paulo, SP - Brazil

^[2] Univ Fed ABC, Ctr Ciencias Nat & Humanas, Lab Nanoestruturas Biol & Mat Avancados, Santo Andre, SP - Brazil

^[3] Univ Sao Paulo, Inst Fis Sao Carlos, Grp Biofis Mol Sergio Mascarenhas, Sao Carlos, SP - Brazil

• Document type: Journal article
• Source: PLoS One; v. 10, n. 8 AUG 27 2015.
• Web of Science Citations: 4

Abstract

We characterized the peroxidase mechanism of recombinant rat brain cytoglobin (Cygb) challenged by hydrogen peroxide, tert-butylhydroperoxide and by cumene hydroperoxide. The peroxidase mechanism of Cygb is similar to that of myoglobin. Cygb challenged by hydrogen peroxide is converted to a Fe4+ oxoferryl p cation, which is converted to Fe4+ oxoferryl and tyrosyl radical detected by direct continuous wave-electron paramagnetic resonance and by 3,5-dibromo-4-nitrosobenzene sulfonate spin trapping. When organic peroxides are used as substrates at initial reaction times, and given an excess of peroxide present, the EPR signals of the corresponding peroxyl radicals precede those of the direct tyrosyl radical. This result is consistent with the use of peroxide as a reducing agent for the recycling of Cygb high-valence species. Furthermore, we found that the Cygb oxidation by peroxides leads to the formation of amyloid fibrils. This result suggests that Cygb possibly participates in the development of degenerative diseases; our findings also support the possible biological role of Cygb related to peroxidase activity. (AU)

• FAPESP's process: 12/07456-7 - Flow cytometry studies of cell death and protection promoted by porphyrinoid compounds, phenothiazines and Teluranes associated to nanostructures in a cell biology multiuser lab
• Grantee: Iseli Lourenço Nantes Cardoso
• Support Opportunities: Regular Research Grants