Bettina Frangioni

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The structure of the respiratory nitrate reductase (NapAB) from Rhodobacter sphaeroides, the periplasmic heterodimeric enzyme responsible for the first step in the denitrification process, has been determined at a resolution of 3.2 Å. The di-heme electron transfer small subunit NapB binds to the large subunit with heme II in close proximity to the [4Fe-4S](More)
The periplasmic nitrate reductase (NapAB), a member of the DMSO reductase superfamily, catalyzes the first step of the denitrification process in bacteria. In this heterodimer, a di-heme NapB subunit is associated to the catalytic NapA subunit that binds a [4Fe-4S] cluster and a bis(molybdopterin guanine dinucleotide) cofactor. Here, we report the kinetic(More)
The respiratory nitrate reductase (NapAB) from Rb. sphaeroides is a periplasmic molybdenum-containing enzyme which belongs to the DMSO reductase family. We report a study of NapAB by protein film voltammetry (PFV), and we present the first quantitative interpretation of the complex redox-state dependence of activity that has also been observed with other(More)
For redox enzymes, the technique called protein film voltammetry makes it possible to determine the entire profile of activity against driving force by having the enzyme exchanging directly electrons with the rotating-disc electrode onto which it is adsorbed. Both the potential location of the catalytic response and its detailed shape report on the sequence(More)
Each flavocytochrome b(2) (l-lactate cytochrome c oxidoreductase) subunit consists of an N-terminal cytochrome domain and a C-terminal flavodehydrogenase (FDH) domain. In the enzyme crystal structure, only two heme domains are visible per enzyme tetramer, because of the mobility of the other two heme domains relative to the FDH domains. Evidence was(More)
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