Domain architecture of FRD superfamily members.

<p>Models of domain architectures are mapped to the phylogenetic gene trees of bacterial (A) and eukaryotic (B) FRD homologs. Tree branch colors correspond to the color code of the models (see highlight color of model identifiers). The three conserved domains of the ‘eukaryotic structural core’ are colored, and other predicted domains are given in black. Domain forms indicate their function; rounded rectangle = binding of electron donor/hydrogen acceptor: FAD-binding, NADPH-binding (M3), FMN (M4); triangle = electron transfer agent: Ferredoxin/Fer2 (M8), Rieske (M4), DOMON (M10), peroxidase-like domain (M15); circle = regulation of enzyme activity: EF-hands (M14–M16); hexagon = protein-protein interaction: NADPH-oxidase-like domain (M16), SH3 (M17); ellipse = transport of small solutes: MSF (M6).