A multidomain fusion protein in Listeria monocytogenes catalyzes the two primary activities for glutathione biosynthesis

Shubha Gopal, Ilya Borovok, Amos Ofer, Michaela Yanku, Gerald Cohen, Werner Goebel, Jürgen Kreft, Yair Aharonowitz*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Glutathione is the predominant low-molecular-weight peptide thiol present in living organisms and plays a key role in protecting cells against oxygen toxicity. Until now, glutathione synthesis was thought to occur solely through the consecutive action of two physically separate enzymes, γ- glutamylcysteine ligase and glutathione synthetase. In this report we demonstrate that Listeria monocytogenes contains a novel multidomain protein (termed GshF) that carries out complete synthesis of glutathione. Evidence for this comes from experiments which showed that in vitro recombinant GshF directs the formation of glutathione from its constituent amino acids and the in vivo effect of a mutation in GshF that abolishes glutathione synthesis, results in accumulation of the intermediate γ-glutamylcysteine, and causes hypersensitivity to oxidative agents. We identified GshF orthologs, consisting of a γ-glutamylcysteine ligase (GshA) domain fused to an ATP-grasp domain, in 20 gram-positive and gram-negative bacteria. Remarkably, 95% of these bacteria are mammalian pathogens. A plausible origin for GshF-dependent glutathione biosynthesis in these bacteria was the recruitment by a GshA ancestor gene of an ATP-grasp gene and the subsequent spread of the fusion gene between mammalian hosts, most likely by horizontal gene transfer.

Original languageEnglish
Pages (from-to)3839-3847
Number of pages9
JournalJournal of Bacteriology
Volume187
Issue number11
DOIs
StatePublished - Jun 2005

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