basic Helix-Loop-Helix-zipper (bHLHzip) domain found in protein Max-associated protein 1 (Mad1) and similar proteins
Mad1, also termed Max dimerization protein 1 (MXD1), or Max dimerizer 1, or protein MAD, is a bHLHZip transcriptional repressor that binds with MAX to form a sequence-specific DNA-binding protein complex which recognizes the core sequence 5'-CAC[GA]TG-3'. It thus antagonizes MYC transcriptional activity by competing for MAX.