2. Membrane and cell surface proteins and peptides
  3. Heme-binding four-helical bundle

Heme-binding four-helical bundle Fold

Superfamily Families Domains
Transmembrane di-heme cytochromes 2 4
Fumarate reductase respiratory complex transmembrane subunits 2 7
Respiratory nitrate reductase 1 gamma chain 1 1