What question did this study set out to answer?

To characterize the chemical and physical mechanism of oxygen-mediated inactivation of Bacillus subtilis glutamine PRPP amidotransferase and assess how metabolic ligands regulate this stability.

September 29, 1981Biochemistry

Reaction of Bacillus subtilis glutamine phosphoribosylpyrophosphate amidotransferase with oxygen: chemistry and regulation by ligands

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Authors

DBDavid BernlohrUniversity of Minnesota RSRobert L. SwitzerCalifornia Institute of Technology

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Implication

Biochemical analysis demonstrates oxygen-driven inactivation of glutamine PRPP amidotransferase in Bacillus subtilis, indicating allosteric control over enzyme degradation.

Key Points

To characterize the chemical and physical mechanism of oxygen-mediated inactivation of Bacillus subtilis glutamine PRPP amidotransferase and assess how metabolic ligands regulate this stability.
Purified enzyme was subjected to molecular oxygen exposure under varying conditions to assess oxidation chemistry and reactive species participation.
Physical and structural modifications were monitored through circular dichroism spectroscopy, solubility assays, and chemical quantitation of iron and sulfur oxidation states.
Rates of oxidative inactivation were evaluated in the presence of allosteric nucleotide inhibitors (AMP, ADP, GMP, GDP) and the substrate phosphoribosylpyrophosphate.
Molecular oxygen directly oxidized the enzyme's 4Fe-4S center into enzyme-bound high-spin Fe3+ and sulfur species including thiocystine, rather than acting via superoxide or peroxide intermediates.
Oxidation induced gross physical alterations in the enzyme, resulting in structural unfolding, altered circular dichroic spectra, decreased solubility, and aggregation.
Enzyme oxidation rates were strongly modulated by ligands: AMP strongly stabilized the enzyme against inactivation, whereas P-Rib-PP, ADP, GMP, and GDP destabilized the protein and antagonized AMP-mediated protection.

Cite This Study

Bernlohr et al. (1981) studied this question.

synapsesocial.com/papers/6a87011c240d988a48a244eb https://doi.org/10.1021/bi00523a006

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Implication

Biochemical analysis demonstrates oxygen-driven inactivation of glutamine PRPP amidotransferase in Bacillus subtilis, indicating allosteric control over enzyme degradation.

Reaction of Bacillus subtilis glutamine phosphoribosylpyrophosphate amidotransferase with oxygen: chemistry and regulation by ligands

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Implication

Key Points

Cite This Study

Reaction of Bacillus subtilis glutamine phosphoribosylpyrophosphate amidotransferase with oxygen: chemistry and regulation by ligands

Discussion

Member takes

Implication

Key Points

Cite This Study

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