Hetero-dimer of fos (pink) and MafB (cyan)

MafB has been engineered with several mutations to make it prefer dimerization with fos.

Asp and Glu residues are colored red
Arg and Lys residues are colored blue

Design of a bZip Transcription Factor with Homo/Heterodimer-Induced DNA-Binding Preference.
Pogenberg V, Consani Textor L, Vanhille L, Holton SJ, Sieweke MH, Wilmanns M.
Structure. 2014 Feb 11. pii: S0969-2126(14)00009-4. doi: 10.1016/j.str.2013.12.017. [Epub ahead of print]
(PubMed)

2wt7 (PDB)

Homo-dimer of MafB

The potential ion pairing between any two monomers will largely determine whether homo-dimers or hetero-dimers will be favored

2wty (PDB)