GENEALOGY OF REGULATION OF HUMAN SEX AND ADRENAL-FUNCTION, PROSTAGLANDIN ACTION, SNAPDRAGON AND PETUNIA FLOWER COLORS, ANTIBIOTICS, AND NITROGEN-FIXATION - FUNCTIONAL DIVERSITY FROM 2 ANCESTRAL DEHYDROGENASES

Metabolism of steroid hormones by dehydrogenases is an important mechanism for regulating steroid hormone action. Analysis of recently reported amino acid sequences of 11-beta-hydroxysteroid dehydrogenase, 17-beta-hydroxysteroid dehydrogenase, and 3-alpha,20-beta-hydroxysteroid dehydrogenase reveals that they are descended from a common ancestor. Unexpectedly, this superfamily of dehydrogenases has other interesting relatives: 15-hydroxyprostaglandin dehydrogenase, proteins found in nitrogen-fixing bacteria, and enzymes important in the synthesis of antibiotics. The novel lineage of these proteins and the actions of flavonoids in regulating gene transcription in nitrogen-fixing bacteria and mammals provide new insights into the evolution of regulation of gene transcription by intercellular signals in multicellular animals.