... Homeodomain is a DNA-binding domain presented in a number of eukariotic transcription factors that are resposible for regulation of key developmental processes. Homeodomains contain three alpha-helixes forming helix-turn-helix (HTH) topology and a flexible, enriched with basic amino acids N-terminal "hand" (residues 1?9), which changes its conformation during DNA binding. ... Such complexes gain in high specific binding and affinity to DNA. ...