The hotdog fold seen in FabA and FabZ consists of a central alpha helix with beta sheets wrapped around. This allows the formation of a homodimer, with the two proteins forming an active site with conserved histidine and glutamate residues on the central alpha helix.
This fold allows the protein to form an active site between the two subunits, forming a binding tunnel and alkyl chain pocket, allowing the fatty acid to be synthesised efficiently.