TABLE 1.

Chemical structures of the naturally occurring polymyxins

Reprinted by permission from the Springer Nature: Springer, Adv Exp Med Biol, History, chemistry and antibacterial spectrum, Velkov T. et al. Copyright © 2019.

Polymyxin	Fatty Acyl Group	Position 3	Position 6	Position 7	Position 10
A1	(S)-6-Methyloctanoyl	d-Dab	d-Leu	l-Thr	l-Thr
A2	6-Methylheptanoyl	d-Dab	d-Leu	l-Thr	l-Thr
B1	(S)-6-Methyloctanoyl	l-Dab	d-Phe	l-Leu	l-Thr
B2	6-Methylheptanoyl	l-Dab	d-Phe	l-Leu	l-Thr
B3	Octanoyl	l-Dab	d-Phe	l-Leu	l-Thr
B4	Heptanoyl	l-Dab	d-Phe	l-Leu	l-Thr
B5	Nonanoyl	l-Dab	d-Phe	l-Leu	l-Thr
B6	3-Hydroxy-6-methyloctanoyla	l-Dab	d-Phe	l-Leu	l-Thr
B1-Ile	(S)-6-Methyloctanoyl	l-Dab	d-Phe	l-Ile	l-Thr
B2-Ile	6-Methylheptanoyl	l-Dab	d-Phe	l-Ile	l-Thr
Dab3-B1	(S)-6-Methyloctanoyl	d-Dab	d-Phe	l-Leu	l-Thr
Dab3-B2	6-Methylheptanoyl	d-Dab	d-Phe	l-Leu	l-Thr
C1b	6-Methyloctanoyla	l/d-Dab	d-Phe	l-Thr	l-Thr
C2b	6-Methylheptanoyl	l/d-Dab	d-Phe	l-Thr	l-Thr
D1	(S)-6-Methyloctanoyl	d-Ser	d-Leu	l-Thr	l-Thr
D2	6-Methylheptanoyl	d-Ser	d-Leu	l-Thr	l-Thr
E1 (Colistin A)	(S)-6-Methyloctanoyl	l-Dab	d-Leu	l-Leu	l-Thr
E2 (Colistin B)	6-Methylheptanoyl	l-Dab	d-Leu	l-Leu	l-Thr
E3	Octanoyl	l-Dab	d-Leu	l-Leu	l-Thr
E4	Heptanoyl	l-Dab	d-Leu	l-Leu	l-Thr
E7	7-Methyloctanoyl	l-Dab	d-Leu	l-Leu	l-Thr
E1-Ile	(S)-6-Methyloctanoyl	l-Dab	d-Leu	l-Ile	l-Thr
E1-Val	(S)-6-Methyloctanoyl	l-Dab	d-Leu	l-Val	l-Thr
E1-Nva	(S)-6-Methyloctanoyl	l-Dab	d-Leu	l-Nva	l-Thr
E2-Ile	6-Methylheptanoyl	l-Dab	d-Leu	l-Ile	l-Thr
E2-Val	6-Methylheptanoyl	l-Dab	d-Leu	l-Val	l-Thr
E8-Ile	7-Methylnonanoyl	l-Dab	d-Leu	l-Ile	l-Thr
Fb	6-Methyloctanoylc	l/d-Dab	d-Leu/d-Ile	l-Leu/l-Ile/l-Ser	l-Leu/l-Ile/l-Ser
Fb	6-Methylheptanoyl	l/d-Dab	d-Leu/d-Ile	l-Leu/l-Ile/l-Ser	l-Leu/l-Ile/l-Ser
Fb	Octanoyl	l/d-Dab	d-Leu/d-Ile	l-Leu/l-Ile/l-Ser	l-Leu/l-Ile/l-Ser
M1 (Mattacin)	(S)-6-Methyloctanoyl	d-Dab	d-Leu	l-Thr	l-Thr
M2 (Mattacin)	6-Methylheptanoyl	d-Dab	d-Leu	l-Thr	l-Thr
P1	(S)-6-Methyloctanoyl	d-Dab	d-Phe	l-Thr	l-Thr
P2	6-Methylheptanoyl	d-Dab	d-Phe	l-Thr	l-Thr
S1	6-Methyloctanoylc	d-Ser	d-Phe	l-Thr	l-Thr
T1	6-Methyloctanoylc	l-Dab	d-Phe	l-Leu	l-Leu
T2	6-Methylheptanoyl	l-Dab	d-Phe	l-Leu	l-Leu

^aStereochemistry at C3 and C6 not confirmed.

^bPosition of amino acid residues is speculative.

^cStereochemistry at C6 not confirmed.