Cartoons view of Cytochrome b562, a 4-helix bundle. N-terminus is colored blue, C-terminus is red.
Cytochrome b562 transfer electrons by using a heme group. The heme binding site is found between the helices.
The heme is tightly packed between the N-terminus and the C-terminus.
Lederer, F., Glatigny, A., Bethge, P. H., Bellamy, H. D., Mathews, F. S.: Improvement of the 2.5 Angstroms Resolution Model of Cytochrome B562 by Redetermining the Primary Structure and Using Molecular Graphics J.Mol.Biol. 148 pp. 427 (1981) (PubMed)
256b (PDB)