Cys - Cys (-S-S-) disulphide bridges

A disulphide brdige arises when two non-adjacent cysteine (Cys) residues are brought together to form a covalent -S-S- bond. Disulphide bridges can form between residues hundreds of residues apart, or between subunit chains in the tertiary or quaternary structures.

Figure © 2012 TA Brown, Introduction to Genetics (1st ed.); additional text © 2015 by Steven M. Carr