Cu/Zn-superoxide dismutase and wild-type like fALS SOD1 mutants produce cytotoxic quantities of H2O2 via cysteine-dependent redox short-circuit

Shamchal Bakavayev, Nimrod Chetrit, Tatiana Zvagelsky, Rasha Mansour, Maria Vyazmensky, Zeev Barak, Adrian Israelson, Stanislav Engel

Research output: Contribution to journalArticlepeer-review

12 Scopus citations

Abstract

The Cu/Zn−superoxide dismutase (SOD1) is a ubiquitous enzyme that catalyzes the dismutation of superoxide radicals to oxygen and hydrogen peroxide. In addition to this principal reaction, the enzyme is known to catalyze, with various efficiencies, several redox side-reactions using alternative substrates, including biological thiols, all involving the catalytic copper in the enzyme’s active-site, which is relatively surface exposed. The accessibility and reactivity of the catalytic copper is known to increase upon SOD1 misfolding, structural alterations caused by a mutation or environmental stresses. These competing side-reactions can lead to the formation of particularly toxic ROS, which have been proposed to contribute to oxidative damage in amyotrophic lateral sclerosis (ALS), a neurodegenerative disease that affects motor neurons. Here, we demonstrated that metal-saturated SOD1WT (holo-SOD1WT) and a familial ALS (fALS) catalytically active SOD1 mutant, SOD1G93A, are capable, under defined metabolic circumstances, to generate cytotoxic quantities of H2O2 through cysteine (CSH)/glutathione (GSH) redox short-circuit. Such activity may drain GSH stores, therefore discharging cellular antioxidant potential. By analyzing the distribution of thiol compounds throughout the CNS, the location of potential hot-spots of ROS production can be deduced. These hot-spots may constitute the origin of oxidative damage to neurons in ALS.

Original languageEnglish
Article number10826
JournalScientific Reports
Volume9
Issue number1
DOIs
StatePublished - 1 Dec 2019

ASJC Scopus subject areas

  • General

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