Glyceraldehyde-3-phosphate dehydrogenase from Citrobacter sp. S-77 is post-translationally modified by CoA (protein CoAlation) under oxidative stress

Kohsei Tsuji, Ki Seok Yoon, Seiji Ogo

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Protein CoAlation (S-thiolation by coenzyme A) has recently emerged as an alternative redox-regulated post-translational modification by which protein thiols are covalently modified with coenzyme A (CoA). However, little is known about the role and mechanism of this post-translational modification. In the present study, we investigated CoAlation of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) from a facultative anaerobic Gram-negative bacterium Citrobacter sp. S-77 (CbGAPDH). GAPDH is a key glycolytic enzyme whose activity relies on the thiol-based redox-regulated post-translational modifications of active-site cysteine. LC-MS/MS analysis revealed that CoAlation of CbGAPDH occurred in vivo under sodium hypochlorite (NaOCl) stress. The purified CbGAPDH was highly sensitive to overoxidation by H 2 O 2 and NaOCl, which resulted in irreversible enzyme inactivation. By contrast, treatment with coenzyme A disulphide (CoASSCoA) or H 2 O 2 /NaOCl in the presence of CoA led to CoAlation and inactivation of the enzyme; activity could be recovered after incubation with dithiothreitol, glutathione and CoA. CoAlation of the enzyme in vitro was confirmed by mass spectrometry. The presence of a substrate, glyceraldehyde-3-phosphate, fully protected CbGAPDH from inactivation by CoAlation, suggesting that the inactivation is due to the formation of mixed disulphides between CoA and the active-site cysteine Cys149. A molecular docking study also supported the formation of mixed disulphide without steric constraints. These observations suggest that CoAlation is an alternative mechanism to protect the redox-sensitive thiol (Cys149) of CbGAPDH against irreversible oxidation, thereby regulating enzyme activity under oxidative stress.

Original languageEnglish
Pages (from-to)53-73
Number of pages21
JournalFEBS Open Bio
Volume9
Issue number1
DOIs
Publication statusPublished - Jan 2019

All Science Journal Classification (ASJC) codes

  • Biochemistry, Genetics and Molecular Biology(all)

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