Basic domains Basic helix-span-helix factors (bHSH) CLASSLINK:http\://www.edgar-wingender.de/class 1.3.html Class TRANSFAC class description C0032: Examining human AP-2 as paradigm of this structural class, a DNA-contacting domain was identified which comprises several clusters of basic amino acid side chains. C-terminally adjacent to it, a dimerization domain was found which consists of two putative alpha-helices separated by a span of over 80 amino acids. This HSH dimerization domain can functionally replace the ZIP dimerization domain of c-Jun. (PMID 1998122)