Rubredoxin (PDB 2rxn) ribbon diagram, with non-heme Fe. Hand-drawn by Jane Richardson in 1981.
<a href="//commons.wikimedia.org/wiki/User:Dcrjsr" title="User:Dcrjsr">Dcrjsr</a>
CC BY 3.0
<span class="int-own-work" lang="en">Own work</span>