Primary structures of representative class II bacteriocins isolated/studied in our laboratory. Enterocin NKR-5-3C (Ent53C) is a novel class IIa (pediocin-like) bacteriocin. The conserved YGNGV (but in the case of Ent53C, V is replaced with L, shown in gray residue) and cysteine residues involved in disulfide bridges are highlighted in black (A). Lactococcin Q is a novel class IIb (two-peptide) bacteriocin, which is comprised of two peptides (Qα and Qβ) that show synergistic activity with each other (B). Lactocyclicin Q (LycQ) and leucocyclicin Q (LcyQ) are novel class IIc (circular) bacteriocins. Residues in red represent the replaced residues to constitute for LcyQ. N- and C- terminal residues involved in the head-to-tail cyclization are shown in dark residues (C). Lacticin Q and lacticin Z are leaderless (class IId) bacteriocins with a formylated methionine residue (fM) at the first N-terminal residue. Residues in red represent the replaced residues to constitute for lacticin Z (D).