An HLH dimer in which both subunits are of the bHLH type can bind DNA, but a dimer in which one subunit lacks the basic region cannot bind DNA.

• DNA结合蛋白有两个共同特征；即存在结合DNA的螺旋区和形成蛋白质二聚体的能力.；螺旋-环-螺旋蛋白同时具有这两特征