A short linker and nucleotide binding a/b domains (NBD) that contain conserved Walker boxes A (p-loop 155-161) and B (239-243) follow the N-terminal CARD domain. The Walker boxes A/B are critical for dATP/ATP and Mg2+ binding. Following the NBD is a small helical domain (HD1), a second linker and a conserved winged helix domain (WHD). The NOD region comprises NBD, HD1 and WHD, creating an ATPase domain that is part of the AAA+ family of ATPases. There is a super helical domain (HD2) present in the junction between the NOD and the WD-40 repeats. The WD40 repeats are in groups of eight and seven with linkers connecting them.