| Title |
Redox properties of Bacillus subtilis ferredoxin:NADP+ oxidoreductase: potentiometric characteristics and reactions with pro-oxidant xenobiotics / |
| Authors |
Lesanavičius, Mindaugas ; Seo, Daisuke ; Maurutytė, Gintarė ; Čėnas, Narimantas |
| DOI |
10.3390/ijms25105373 |
| Full Text |
|
| Is Part of |
International journal of molecular sciences.. Basel : MDPI. 2024, vol. 25, iss. 10, art. no. 5373, p. [1-16].. eISSN 1422-0067 |
| Keywords [eng] |
quinones ; nitroaromatics ; flavins ; redox cycling ; ferredoxin:NADP+ oxidoreductase ; single-electron reduction |
| Abstract [eng] |
Bacillus subtilis ferredoxin:NADP+ oxidoreductase (BsFNR) is a thioredoxin reductase-type FNR whose redox properties and reactivity with nonphysiological electron acceptors have been scarcely characterized. On the basis of redox reactions with 3-acetylpyridine adenine dinucleotide phosphate, the two-electron reduction midpoint potential of the flavin adenine dinucleotide (FAD) cofactor was estimated to be −0.240 V. Photoreduction using 5-deazaflavin mononucleotide (5-deazaFMN) as a photosensitizer revealed that the difference in the redox potentials between the first and second single-electron transfer steps was 0.024 V. We examined the mechanisms of the reduction of several different groups of non-physiological electron acceptors catalyzed by BsFNR. The reactivity of quinones and aromatic N-oxides toward BsFNR increased when increasing their single-electron reduction midpoint redox potentials. The reactivity of nitroaromatic compounds was lower due to their lower electron self-exchange rate, but it exhibited the same trend. A mixed single- and two-electron reduction reaction was characteristic of quinones, whereas reactions involving nitroaromatics proceeded exclusively via the one-electron reduction reaction. The oxidation of FADH• to FAD is the rate-limiting step during the oxidation of fully reduced FAD. The calculated electron transfer distances in the reaction with nitroaromatics were close to those of other FNRs including the plant-type enzymes, thus demonstrating their similar active site accessibility to low-molecular-weight oxidants despite the fundamental differences in their structures. |
| Published |
Basel : MDPI |
| Type |
Journal article |
| Language |
English |
| Publication date |
2024 |
| CC license |
|
