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Table. 1.

Table. 1.

Classification and characteristics of bacteriocins.

Bacteriocin class structure Characteristics Bacteriocin
The Lantibiotics (Class I) Class I are post-translationally modified peptides (<5 kDa). Extensive post-translational modifications occur in the pro-peptide region in the serine, threonine, and cysteine residues. Class Ia: linear lantibiotics Heat stable at 121℃ for prolonged heating at pH 2. Become less heat stable at pH 5-7. Nisin
Class Ib: globular lantibiotics Heat stable at 100°C for 60 min. Most stable at acid and neutral pH. Lacticin 3147A
Class Ic require two or more modified peptides to be functional. Resistant to pepsin, proteinase K, a-amylase, and lipase. Plantaricin C
The unmodified peptides (Class II) The class II bacteriocins are composed of translationally unmodified small peptides (< 10 kDa). Class IIa consist of a disulphide bridge formed by cysteine residues at their N- terminal region. Stable at pH 4 to 6, Heat stable at 100℃for 10 min. Pediocin PA-1
Class IIb require the aid of two or more non-modified peptides for eliciting antimicrobial activity. Stable at pH 3 to12, Heat stable at 100℃ for 60 min. Enterocin 1071
Class IIc are single peptide non-pediocin like bacteriocins which are a heterogeneous group Stable under mild heat conditions and sensitive to proteolytic enzymes Enterocin EJ97
Large proteins (Class III) Class III are large proteinaceous (>30 kDa) heat labile bacteriocins. Their primary structure consists of binding domain and an N-terminal catalytic domain. Class IIIa are considered as lytic bacteriocins. Class IIIa attack the peptidoglycan layer of the cell wall in susceptible gram-positive bacterial targets. Enterolysin A
Class IIIb are non-lytic heat labile bacteriocins. Class IIIb can hamper the glucose uptake by the cells and starves them and also disturbs the membrane potential. Helveticin J, Streptococcin A-M57, and Dysgalacticin
Circular peptides (Class IV) Class IV is a cyclization formed by the ligation of their N-terminus to the C-terminus via an amide bond, and they have a molecular weight of 5.5–7.5 kDa Active at pH 9.0 and in combination with moderate heat treatment. Inactivated by heated for 5 min at 65℃ in an alkaline (pH 9.0). Enterocin AS-48
J. Microbiol. Biotechnol. 2019;29:1341~1348 https://doi.org/10.4014/jmb.1905.05060
© J. Microbiol. Biotechnol.