>gnl|CDD|99788 cd06191, FNR_iron_sulfur_binding, Iron-sulfur binding Ferredoxin Reductase (FNR) proteins combine the FAD and NAD(P) binding regions of FNR with a C-terminal iron-sulfur binding cluster domain. FNR was intially identified as a chloroplast reductase activity catalyzing the electron transfer from reduced iron-sulfur protein ferredoxin to NADP+ as the final step in the electron transport mechanism of photosystem I. FNR transfers electrons from reduced ferredoxin to FAD (forming FADH2 via a semiquinone intermediate) and then transfers a hydride ion to convert NADP+ to NADPH. FNR has since been shown to utilize a variety of electron acceptors and donors and has a variety of physiological functions including nitrogen assimilation, dinitrogen fixation, steroid hydroxylation, fatty acid metabolism, oxygenase activity, and methnae assimilation in a variety of organisms. FNR has an NAD(P)-binding sub-domain of the alpha/beta class and a discrete (usually N-terminal) flavin sub-domain which vary in orientation with respect to the NAD(P) binding domain. The N-terminal moeity may contain a flavin prosthetic group (as in flavoenzymes) or use flavin as a substrate. Because flavins such as FAD can exist in oxidized, semiquinone (one- electron reduced), or fully reduced hydroquinone forms, FNR can interact with one and 2 electron carriers. FNR has a strong preference for NADP(H) vs NAD(H).. Length = 231

 Score = 64.9 bits (158), Expect = 2e-11
 Identities = 35/111 (31%), Positives = 53/111 (47%), Gaps = 3/111 (2%)

Query: 26  RLFRFCITRPKSFRFRSGEFVMLGLIVNGRPIFRAYSIASPCRDDKLEFCSIKVDKGFFT 85
               F +  P  + FR G+ V L L  +G  + R YS+ S    D++     +V  G  +
Sbjct: 14  VTIVFAVPGPLQYGFRPGQHVTLKLDFDGEELRRCYSLCSSPAPDEISITVKRVPGGRVS 73

Query: 86  TYL-QNIQPGDTILLHKKSTGDLILDSLIPGNRLYLFSMGTGIAPFASMIR 135
            YL ++IQPG T+ +     G  +     PG R  L + G+GI P  +MIR
Sbjct: 74  NYLREHIQPGMTVEV-MGPQGHFVYQPQPPG-RYLLVAAGSGITPLMAMIR 122