TRX-GRX-like family, Alkyl hydroperoxide reductase F subunit (AhpF) N-terminal domain (NTD) subfamily, C-terminal TRX-fold subdomain; AhpF is a homodimeric flavoenzyme which catalyzes the NADH-dependent reduction of the peroxiredoxin AhpC, which then reduces hydrogen peroxide and organic hydroperoxides. AhpF contains an NTD containing two contiguous TRX-fold subdomains similar to Pyrococcus furiosus protein disulfide oxidoreductase (PfPDO). It also contains a catalytic core similar to TRX reductase containing FAD and NADH binding domains with an active site disulfide. The proposed mechanism of action of AhpF is similar to a TRX/TRX reductase system. The flow of reducing equivalents goes from NADH -> catalytic core of AhpF -> NTD of AhpF -> AhpC -> peroxide substrates. The catalytic CXXC motif of the NTD of AhpF is contained in its C-terminal TRX subdomain.
Comment:The N-terminal domain (NTD) of AhpF, which contains two contiguous TRX folds, mediates electron transfer from the catalytic core of AhpF to its substrate AhpC. The active site CXXC motif of AhpF NTD resides in its C-terminal TRX-fold subdomain.
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