Aim: To identify alkyl hydroperoxide reductase subunit C (AhpC) homologs in Bacillus subtilis (B. subtilis) and to characterize their structural and biochemical properties. AhpC is responsible for the detoxification of reactive oxygen species in bacteria.
Methods: Two AhpC homologs (AhpC_H1 and AhpC_H2) were identified by searching the B. subtilis database; these were then cloned and expressed in Escherichia coli. AhpC mutants carrying substitutions of catalytically important Cys residues (C37S, C47S, C166S, C37/47S, C37/166S, C47/166S, and C37/47/166S for AhpC_H1; C52S, C169S, and C52/169S for AhpC_H2) were obtained by site-directed mutagenesis and purified, and their structure-function relationship was analyzed. The B. subtilis ahpC genes were disrupted by the short flanking homology method, and the phenotypes of the resulting AhpC-deficient bacteria were examined.
Results: Comparative characterization of AhpC homologs indicates that AhpC_H1 contains an extra C37, which forms a disulfide bond with the peroxidatic C47, and behaves like an atypical 2-Cys AhpC, while AhpC_H2 functions like a typical 2-Cys AhpC. Tryptic digestion analysis demonstrated the presence of intramolecular Cys37-Cys47 linkage, which could be reduced by thioredoxin, resulting in the association of the dimer into higher-molecular-mass complexes. Peroxidase activity analysis of Cys→Ser mutants indicated that three Cys residues were involved in the catalysis. AhpC_H1 was resistant to inactivation by peroxide substrates, but had lower activity at physiological H2O2 concentrations compared to AhpC_H2, suggesting that in B. subtilis, the enzymes may be physiologically functional at different substrate concentrations. The exposure to organic peroxides induced AhpC_H1 expression, while AhpC_H1-deficient mutants exhibited growth retardation in the stationary phase, suggesting the role of AhpC_H1 as an antioxidant scavenger of lipid hydroperoxides and a stress-response factor in B. subtilis.
Conclusion: AhpC_H1, a novel atypical 2-Cys AhpC, is functionally distinct from AhpC_H2, a typical 2-Cys AhpC.
Download full-text PDF |
Source |
---|---|
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4549766 | PMC |
http://dx.doi.org/10.4331/wjbc.v6.i3.249 | DOI Listing |
Redox Rep
December 2025
Department of Clinical Laboratory, Shanghai Fourth People's Hospital, School of Medicine, Tongji University, Shanghai, People's Republic of China.
Objectives: Bone remodeling imbalance contributes to osteoporosis. Though current medications enhance osteoblast involvement in bone formation, the underlying pathways remain unclear. This study was aimed to explore the pathways involved in bone formation by osteoblasts, we investigate the protective role of glycolysis and N6-methyladenosine methylation (m6A) against oxidative stress-induced impairment of osteogenesis in MC3T3-E1 cells.
View Article and Find Full Text PDFSmall
December 2024
State Key Laboratory of Bio-fibers and Eco-textiles, Collaborative Innovation Center of Shandong Marine Biobased Fibers and Ecological Textiles, Institute of Marine Biobased Materials, College of Materials Science and Engineering, Qingdao University, Qingdao, 266071, P. R. China.
Polymer gels, renowned for unparalleled chemical stability and self-sustaining properties, have garnered significant attention in electrocatalysis. Notably, organic polymer gels that exhibit temperature sensitivity and incorporate suitable polar nonvolatile liquids, enhance electronic conductivity, and impart distinct morphological features, but remain largely unexplored as electrocatalysts for oxygen reduction reaction (ORR). To address this issue, an innovative strategy is proposed for synergistic modulation of the rigidity of mainchain molecular skeleton and length of alkyl sidechains, enabling the development of organogel polymers with a sol-gel temperature-sensitive phase transition that promises high selectivity and enhanced activity in electrocatalytic processes.
View Article and Find Full Text PDFAnal Methods
December 2024
Universite Claude Bernard Lyon 1, ISA UMR 5280, CNRS, 5 rue de la Doua, 69100 Villeurbanne, France.
The characterization of industrial working solutions containing numerous structurally related compounds and isomers requires the use of two-dimensional liquid chromatography coupled with high-resolution mass spectrometry (LC × LC-HRMS). The separation of alkyl-anthraquinone derivatives produced during hydrogen peroxide production was achieved by coupling a biphenyl and a C18 in the first and second dimensions, combined with the use of continuous shifting gradients in the second dimension (D). The use of shifting gradients offers a significant advantage over regular gradients, with a 20% increase in occupancy and better separation of isomers eluted within the same modulation.
View Article and Find Full Text PDFMolecules
November 2024
Pharmaceutical Chemistry and Centre of Excellence for Pharmaceutical Sciences, North-West University, Potchefstroom 2520, South Africa.
Monoamine oxidase (MAO) plays a key role in the pathogenesis of central nervous system disorders, and MAO inhibitors have been used in the treatment of depression and Parkinson's disease. In the search for new classes of MAO inhibitors, the present study investigated a series of 1,2,4-oxadiazin-5(6)-one derivatives. This study provides the first optimization of the reaction conditions for the condensation of amidoximes with alkyl 2-halocarboxylates to yield the desired 1,2,4-oxadiazin-5(6)-ones.
View Article and Find Full Text PDFChem Asian J
December 2024
Department of Chemistry, Birla Institute of Technology and Science, Pilani, Pilani Campus, Rajasthan, 333031, India.
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!