skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Indole N ‐Linked Hydroperoxyl Adduct of Protein‐Derived Cofactor Modulating Catalase‐Peroxidase Functions
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.  more » « less
Award ID(s):
2204225
PAR ID:
10558559
Author(s) / Creator(s):
 ;  ;  ;  ;  ;  ;  ;  ;  
Publisher / Repository:
Wiley Blackwell (John Wiley & Sons)
Date Published:
Journal Name:
Angewandte Chemie International Edition
Volume:
63
Issue:
49
ISSN:
1433-7851
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. (, Critical Reviews in Biochemistry and Molecular Biology)
    Cox, Michael M (Ed.)
    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. 
    more » « less
  2. ; ; ; ; ; (, mSystems)
    Traxler, Matthew F. (Ed.)
    ABSTRACT Polymicrobial biofilms are present in many environments particularly in the human oral cavity where they can prevent or facilitate the onset of disease. While recent advances have provided a clear picture of both the constituents and their biogeographic arrangement, it is still unclear what mechanisms of interaction occur between individual species in close proximity within these communities. In this study, we investigated two mechanisms of interaction between the highly abundant supragingival plaque (SUPP) commensalCorynebacterium matruchotiiandStreptococcus mitiswhich are directly adjacent/attachedin vivo. We discovered thatC. matruchotiienhanced the fitness of streptococci dependent on its ability to detoxify streptococcal-produced hydrogen peroxide and its ability to oxidize lactate also produced by streptococci. We demonstrate that the fitness of adjacent streptococci was linked to that ofC. matruchotiiand that these mechanisms support the previously described “corncob” arrangement between these species but that this is favorable only in aerobic conditions. Furthermore, we utilized scanning electrochemical microscopy to quantify lactate production and consumption between individual bacterial cells for the first time, revealing that lactate oxidation provides a fitness benefit toS. mitisnot due to pH mitigation. This study describes mechanistic interactions between two highly abundant human commensals that can explain their observedin vivospatial arrangements and suggest a way by which they may help preserve a healthy oral bacterial community. IMPORTANCEAs the microbiome era matures, the need for mechanistic interaction data between species is crucial to understand how stable microbiomes are preserved, especially in healthy conditions where the microbiota could help resist opportunistic or exogenous pathogens. Here we reveal multiple mechanisms of interaction between two commensals that dictate their biogeographic relationship to each other in previously described structures in human supragingival plaque. Using a novel variation for chemical detection, we observed metabolite exchange between individual bacterial cells in real time validating the ability of these organisms to carry out metabolic crossfeeding at distal and temporal scales observedin vivo. These findings reveal one way by which these interactions are both favorable to the interacting commensals and potentially the host. 
    more » « less
  3. ; ; ; ; ; ; ; (, Inorganic Chemistry Frontiers)
    null (Ed.)
    The catalase family of enzymes, which include a variety with a binuclear manganese active site, mitigate the risk from reactive oxygen species by facilitating the disproportionation of hydrogen peroxide into molecular oxygen and water. In this work, hydrogen peroxide disproportionation using complexes formed between manganese and cyclen or pyclen were investigated due to the spectroscopic similarities with the native MnCAT enzyme. Potentiometric titrations were used to construct speciation diagrams that identify the manganese complex compositions at different pH values. Each complex behaves as a functional mimic of catalase enzymes. UV-visible spectroscopic investigations of the H 2 O 2 decomposition reaction yielded information about the structure of the initial catalyst and intermediates that include monomeric and dimeric species. The results indicate that rigidity imparted by the pyridine ring of pyclen is a key factor in increased TON and TOF values measured compared to cyclen. 
    more » « less
  4. ; ; ; ; ; ; (, Plant Direct)
    Abstract Photorespiration recovers carbon that would be otherwise lost following the oxygenation reaction of rubisco and production of glycolate. Photorespiration is essential in plants and recycles glycolate into usable metabolic products through reactions spanning the chloroplast, mitochondrion, and peroxisome. Catalase in peroxisomes plays an important role in this process by disproportionating H2O2resulting from glycolate oxidation into O2and water. We hypothesize that catalase in the peroxisome also protects against nonenzymatic decarboxylations between hydrogen peroxide and photorespiratory intermediates (glyoxylate and/or hydroxypyruvate). We test this hypothesis by detailed gas exchange and biochemical analysis ofArabidopsis thalianamutants lacking peroxisomal catalase. Our results strongly support this hypothesis, with catalase mutants showing gas exchange evidence for an increased stoichiometry of CO2release from photorespiration, specifically an increase in the CO2compensation point, a photorespiratory‐dependent decrease in the quantum efficiency of CO2assimilation, increase in the12CO2released in a13CO2background, and an increase in the postillumination CO2burst. Further metabolic evidence suggests this excess CO2release occurred via the nonenzymatic decarboxylation of hydroxypyruvate. Specifically, the catalase mutant showed an accumulation of photorespiratory intermediates during a transient increase in rubisco oxygenation consistent with this hypothesis. Additionally, end products of alternative hypotheses explaining this excess release were similar between wild type and catalase mutants. Furthermore, the calculated rate of hydroxypyruvate decarboxylation in catalase mutant is much higher than that of glyoxylate decarboxylation. This work provides evidence that these nonenzymatic decarboxylation reactions, predominately hydroxypyruvate decarboxylation, can occur in vivo when photorespiratory metabolism is genetically disrupted. 
    more » « less
  5. ; ; ; (, Applied Surface Science)
    Oxidations represent important reactions that are ubiquitous in academia and industry. Hydrogen peroxide (H2O2) is a common source of active oxygen for oxidations. H2O2 is usually diluted in water as it is too unstable to be used in pure form. However, the presence of water can complicate reactions because biphasic mixtures with organic solvents form. Furthermore, secondary reactions with water may lead to side products. Therefore, alternative forms of H2O2, such as peroxide adducts, are an active area of research. Di(hydroperoxy)alkane adducts of phosphine oxides are one attractive solution because they are soluble in organic solvents, crystallizable, shelf-stable and active towards a variety of oxidation reactions. The only drawback is that the phosphine oxide carrier has to be removed after the reaction. In this contribution, the bifunctional ligand (EtO)3Si(CH2)2PPh2 is immobilized on a silica (SiO2) support which is subsequently end-capped with EtOSi(CH3)3. The new surface-bound di(hydroperoxy)propane adduct is then generated with the immobilized phosphine oxide as carrier. The adduct and a deuterated analog are characterized with solid-state and solution NMR spectroscopy. It has been demonstrated that substrates in organic solvents easily access the surface-bound peroxide and are oxidized quantitatively. The phosphine oxide carrier remains bound to the surface and can be removed easily by settling of the silica. Using the oxidative esterification of nonyl aldehyde it is proven that the immobilized peroxide adduct does not leach from the silica support and is active and reusable over multiple cycles. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email