Fig. 4.

FFTR working model. FFTR might explore different conformation states during its catalytic cycle. (A) In the FR state, the isoalloxazine group of the flavin cofactor is exposed for interaction with Fdx, and (B) the CxxC motif of FFTR can interact with oxidized Trx for reduction. (C) Reduction of the bound FAD cofactor would induce a conformational change that is propagated to the second domain in a redox-associated conformational change that results in the FO conformation. In this conformation, the disulfide of FFTR is reduced by FAD. Dashed arrows indicate hypothetical reducing equivalent flow for monomer A.