Lanthionine is formed by cysteine and dehydrated serine, while methyl-lanthionine derives from the coupling of cysteine and threonine . The inclusion of lanthionine enables lantibiotics to form mono-sulfide bridges, contributing to a partially cyclic, rigid macrocyclic structure that "cages" the pyrophosphate moiety of lipid II, as shown in Figure . Lantibiotics may also have more than one mono-sulfide bridge, that result in complex macrocyclic structures (e.g., Nisin in Figure with the monosulfide bridges marked in blue).