text: A fourth and final C-terminal helix, extending from residue 184 to the C-terminus, forms a long domainswapped helix that is significantly kinked at residues 211– 213 and is packed against its symmetry mate, forming an amphipathic two-helix bundle structure and inter-subunit contacts that closely resemble an antiparallel coiled-coil peptide fold (23) (Figure 2B).