Many proteins that have crucial roles in cellular physiology require iron to function.
- Heme proteins
- Components of the mitochondrial electron-transport chain
- ferrochelatase?? which is indispensable for haem synthesis
- Enzymes involved in DNA synthesis, replication, repair and transcription
- ribonucleotide reductase
- DNA primase
- DNA helicases, bind iron
- ATPase ABCE1, which is needed for mRNA translation, incorporates iron.
Many of these proteins are highly conserved across prokaryotes and eukaryotes, and the central position of iron in cellular metabolism is maintained in almost all forms of life.
Cellular iron deficiency abrogates the activity of iron-dependent proteins and disrupts the proper functioning of cellular processes.
The widespread use of iron can be accounted for by
- its ability to shuttle electrons,
- its flexibility for binding ligands in diverse orientations
- its high bioavailability during the early stages of evolution under the reducing conditions of a sulphur-rich atmosphere.