FIG 7.

Schematic of the proposed mechanism for transcriptional activation by AdhR. Under oxidative-stress or iron-limited conditions, the AAA⁺ domain is subject to repression by the GAF and PAS domains in AdhR. Under anaerobic and iron-replete conditions, binding of Fe²⁺ to the GAF domain relieves the repression on the AAA⁺ domain. AdhR is then able to hydrolyze ATP, leading to the σ⁵⁴-dependent transcription of adhA1 and adhA2, encoding ADHs that catalyze the NAD(P)H-dependent conversion of aldehydes to alcohols.