Mechanistic insights into redox activity and catalytic determinants of the haloarchaeal flavin-dependent oxidoreductase Hv FdR.

Biochemical and physiological characterization of a haloarchaeal oxidoreductase

“Here, we define the biochemical and physiological functions of the Haloferax volcanii flavin-dependent oxidoreductase Hv FdR (HVO_2345; fdr ), a haloarchaeal member of a previously uncharacterized IPR050260 subgroup.”

Haloferax volcanii flavin-dependent oxidoreductase Hv FdR

“Here, we define the biochemical and physiological functions of the Haloferax volcanii flavin-dependent oxidoreductase Hv FdR (HVO_2345; fdr ), a haloarchaeal member of a previously uncharacterized IPR050260 subgroup.”

Hv FdR catalyzes NAD(P)H oxidase, diaphorase, and ferredoxin reductase activities with a preference for NADPH

“Hv FdR binds FAD and catalyzes NAD(P)H oxidase, diaphorase and ferredoxin reductase activities, with a kinetic preference for NADPH over NADH and catalytic properties that are strongly influenced by oxygen availability.”

Deletion of fdr impairs growth and elevates intracellular NADPH levels

“Deletion of fdr impairs growth and elevates intracellular NADPH levels, consistent with a role for Hv FdR in maintaining NADP(H) homeostasis.”

Conserved residues K47 and Y323 are determinants of electron transfer activity

“Conserved residues K47 and Y323 are identified as determinants of Hv FdR electron transfer activity and may function as a regulatory gate that modulates electron flow while limiting excessive H 2 O 2 production under aerobic conditions.”