Structural domains comprising this superfamily share the structure of the N-terminal helical oligemrization domain of Malonyl-CoA decarboxylase (MCD), enzyme which catalyzes the conversion of malonyl-CoA to acetyl-CoA and CO2 and is localized in peroxisomes, and more abundantly in the cytoplasm. MCD is found from bacteria to humans and it has important roles in regulating fatty acid metabolism and food intake. This N-terminal helical domain is involved in the oligomerization of MCDs, although there are important differences in the organization of the dimers and tetramers among MCD orthologs PMID:23791943.