Metal ions are paramount for metabolic processes in living organisms. The nature of metabolic processes depend on the proteins involved, that are formed from amino acids. Cysteine is special as it can form complexes with metal ions due to its thiol group at the end of the R chain. For example its ability to bind to nickel ions.
- ↑ A novel cysteine-rich sequence motif. Cell. 1991 Feb 8;64:483-4.