Lacticin 3147 is a lantibiotic with seven lanthionine bridges across its two component peptides, Ltn alpha and Ltn beta Although it has been proposed that the eponymous lanthionine and (beta-methyl)lanthionine (Lan and meLan) bridges present in lantibiotics make an important contribution to protecting the peptides from thermal or proteolytic degradation, few studies have investigated this link We have generated a bank of bioengineered derivatives of lacticin 3147, in which selected bridges were removed or converted between Lan and meLan, which were exposed to high temperature or proteolytic enzymes Although switching Lan and meLan bridges has variable consequences, it was consistently observed that an intact N-terminal lanthionine bridge (Ring A) confers Ltna with enhanced resistance to thermal and proteolytic degradation