This basic domain is found in the MyoD family of muscle specific proteins that control muscle development. The bHLH region of the MyoD family includes the basic domain and the Helix-loop-helix (HLH) motif. The bHLH region mediates specific DNA binding [1]. With 12 residues of the basic domain involved in DNA binding [2]. The basic domain forms an extended alpha helix in the structure.

1: The basic domain of myogenic basic helix-loop-helix (bHLH) proteins is the novel target for direct inhibition by another bHLH protein, Twist. Hamamori Y, Wu HY, Sartorelli V, Kedes L; Mol Cell Biol 1997;17:6563-6573. PMID:9343420

2: Combinatorial control of muscle development by basic helix-loop-helix and MADS-box transcription factors. Molkentin JD, Olson EN; Proc Natl Acad Sci U S A 1996;93:9366-9373. PMID:8790335