Table 9.

A universal classification of antimicrobial peptides

Class	Chain linkage	Subclass	Link type	Class symbol	Examples
I	Linear & open chains^a	1. One chain	None	UCLL1^a	LL-37, magainins
I	Linear & open chains^a	2. Two chains	None	UCLL2	Enterocin L50
II	Sidechain- Sidechain	1. One chain	C^β-S-S-C^β (Disulfide- bond)	UCSS1a^a	Defensin-like
		1. One chain	C^β-S-C^β (thioether)	UCSS1b^a	lantibiotics
		2. Two chains	Inter-chain C^β-S-S-C^β	UCSS2a	Distinctin, halocidin, centrocin
		2. Two chains	Intra-chain C^β-S-C^β	UCSS2b	Lacticin-3147, Smb
III	Sidechain- Backbone	One chain	CO-NH amide	UCSB1a	Microcin J25, Lariatins
			CO-O ester	UCSB1b	Fusaricidin A
			C^β-S-C^α	UCSB1c	Thuricin CD
IV	Backbone- Backbone	One chain	CO-NH amide	UCBB1a^a	AS-48, subtilosin A, cyclotides, θ- defenins

Further classifications are provided in Tables 10-13.