POU Domain (Molecular Biology)

The POU "domain" is a conserved sequence motif defining a family of eukaryotic transcription factors that contains two structurally independent DNA-binding domains connected by a flexible linker of variable length and sequence. Both domains make sequence-specific contacts with DNA and together bind with high affinity to a conserved octameric binding site, ATGCAAAT. The N-terminal domain, POUS, is a four-helix bundle similar in structure to the bacterial helix-turn-helix domain, while the distal domain, POUH, is structurally homologous to the homeobox domain.