Crystal structure of the catalytic core component of the alkylhydroperoxide reductase AhpF from Escherichia coli

Alkylhydroperoxide reductases (AhpR, EC 1.6.4.*) are essential for the oxyg en tolerance of aerobic organisms by converting otherwise toxic hydroperoxi des of lipids or nucleic acids to the corresponding alcohols. The AhpF: com ponent belongs to the family of pyridine nucleotide-disulphide oxidoreducta ses and channels electrons from NAD(P)H towards the AhpC component which fi nally reduces cognate substrates. The structure of the catalytic core of th e Escherichia coli AhpF (A212-A521) with a bound FAD cofactor was determine d at 1.9 Angstrom resolution in its oxidized state. The dimeric arrangement of the AhpF catalytic core and the predicted interaction mode between the N-terminal PDO-like domain and the NADPH domain favours an intramolecular e lectron transfer between the two redox-active disulphide centres of AhpF. ( C) 2001 Academic Press.