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Abstract Bifunctional catalase‐peroxidase (KatG) features a posttranslational methionine‐tyrosine‐tryptophan (MYW) crosslinked cofactor crucial for its catalase function, enabling pathogens to neutralize hydrogen peroxide during infection. We discovered the presence of indole nitrogen‐linked hydroperoxyl adduct (MYW‐OOH) inMycobacterium tuberculosisKatG in the solution state under ambient conditions, suggesting its natural occurrence. By isolating predominantly MYW‐OOH‐containing KatG protein, we investigated the chemical stability and functional impact of MYW‐OOH. We discovered that MYW‐OOH inhibits catalase activity, presenting a unique temporary lock. Exposure to peroxide or increased temperature removes the hydroperoxyl adduct from the protein cofactor, converting MYW‐OOH to MYW and restoring the detoxifying ability of the enzyme against hydrogen peroxide. Thus, theN‐linked hydroperoxyl group is releasable. KatG with MYW‐OOH represents a catalase dormant, but primed, state of the enzyme. These findings provide insight into chemical strategies targeting the bifunctional enzyme KatG in pathogens, highlighting the role ofN‐linked hydroperoxyl modifications in enzymatic function.
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This content will become publicly available on February 27, 2026
Catalase-peroxidase (KatG): a potential frontier in tuberculosis drug development
Mycobacterium tuberculosis (Mtb) depends on the bifunctional enzyme catalase-peroxidase (KatG) for survival within the host. KatG exhibits both catalase and peroxidase activities, serving distinct yet critical roles. While its peroxidase activity is essential for activating the frontline tuberculosis drug isoniazid, its catalase activity protects Mtb from oxidative stress. This bifunctional enzyme is equipped with a unique, protein-derived cofactor, methionine-tyrosine-tryptophan (MYW), which enables catalase activity to efficiently disproportionate hydrogen peroxide in phagocytes. Recent studies reveal that the MYW cofactor naturally exists in a hydroperoxylated form (MYW-OOH) when cell cultures are grown under ambient conditions. New findings highlight a dynamic regulation of KatG activity, wherein the modification of the protein cofactor is removable-from MYW-OOH to MYW-at body temperature or in the presence of micromolar concentrations of hydrogen peroxide. This reversible modification modulates KatG's dual activities: MYW-OOH inhibits catalase activity while enhancing peroxidase activity, demonstrating the chemical accessibility of the cofactor. Such duality positions KatG as a unique target for tuberculosis drug development. Therapeutic strategies that exploit cofactor modification could hold promise, particularly against drug-resistant strains with impaired peroxidase activity. By selectively inhibiting catalase activity, these approaches would render Mtb more vulnerable to oxidative stress while enhancing isoniazid activation-a double-edged strategy for combating tuberculosis.
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- Award ID(s):
- 2204225
- PAR ID:
- 10623859
- Editor(s):
- Cox, Michael M
- Publisher / Repository:
- Taylor & Francis Group
- Date Published:
- Journal Name:
- Critical Reviews in Biochemistry and Molecular Biology
- Volume:
- 59
- Issue:
- 6
- ISSN:
- 1040-9238
- Page Range / eLocation ID:
- 434 to 446
- Subject(s) / Keyword(s):
- Bifunctional enzymes drug activation mechanisms oxidative stress defense protein-derived cofactors redox regulation tuberculosis drug target
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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