Table 5.

Overview on naturally occurring actinomycins^a,b

	α-ring	β-ring
(1) Actinomycin D as core structure
Actinomycin D	Thr-D-Val-Pro-Sar-MeVal	Thr-D-Val-Pro-Sar-MeVal
(2) N-demethyl actinomycins
Actinomycin D0	Thr-D-Val-Pro-Sar-MeVal	Thr-D-Val-Pro-Gly-MeVal
N,N′-Didemethyl- actinomycin D	Thr-D-Val-Pro-Gly-MeVal	Thr-D-Val-Pro-Gly-MeVal
(2) C-type actinomycins
Actinomycin C2	Thr-D-Val-Pro-Sar-MeVal	Thr-D-aIle-Pro-Sar-MeVal
Actinomycin C2a	Thr-d-aIle-Pro-Sar-MeVal	Thr-D-Val-Pro-Sar-MeVal
Actinomycin C3	Thr-D-aIle-Pro-Sar-MeVal	Thr-D-aIle-Pro-Sar-MeVal
(3) F-type actinomycins
Actinomycin F8	Thr-D-Val-Sar-Sar-MeVal	Thr-D-Val-Sar-Sar-MeVal
Actinomycin F9	Thr-D-Val-Sar-Sar-MeVal Thr-D-Val-Pro-Sar-MeVal	Thr-D-Val-Pro-Sar-MeVal Thr-D-Val-Sar-Sar-MeVal
(4) X-type actinomycins
Actinomycin X0α	Thr-D-Val-Sar-Sar-MeVal	Thr-D-Val-Hyp-Sar-MeVal
Actinomycin X0β	Thr-D-Val-Pro-Sar-MeVal	Thr-D-Val-Hyp-Sar-MeVal
Actinomycin X0δ	Thr-D-Val-Pro-Sar-MeVal	Thr-D-Val-aHyp-Sar-MeVal
Actinomycin X1a	Thr-D-Val-Sar-Sar-MeVal	Thr-D-Val-OPro-Sar-MeVal
Actinomycin X2	Thr-D-Val-Pro-Sar-MeVal	Thr-D-Val-OPro-Sar-MeVal
(5) Z-type actinomycins
Actinomycin Z1	Thr-D-Val-HMPro-Sar-MeVal	HThr-D-Val-MOPro-Sar-MeAla
Actinomycin Z2	Thr-D-Val-HMPro-Sar-MeVal	Thr-D-Val-MOPro-Sar-MeAla
Actinomycin Z3	Thr-D-Val-HMPro-Sar-MeVal	ClThr-D-Val-MOPro-Sar-MeAla
Actinomycin Z4	Thr-D-Val-MPro-Sar-MeVal	Thr-D-Val-MOPro-Sar-MeAla
Actinomycin Z5	Thr-D-Val-MPro-Sar-MeVal	ClThr-D-Val-MOPro-Sar-MeAla
Actinomycin Zp $(\mathbf{5})$	Thr-D-Val-MPro-Sar-MeVal	Thr-D-Val-MPro-Sar-MeVal
(6) G-type actinomycins
Actinomycin G1	Thr-D-Val-Pro-Sar-MeVal	HThr-D-Val-HMPro-Sar-MeAla
Actinomycin G2	Thr-D-Val-HMPro-Sar-MeVal	ClThr-D-Val-Pro-Sar-MeAla
Actinomycin G3	Thr-D-Val-HMPro-Sar-MeVal	HThr-d-Val-Pro-Sar-MeAla
Actinomycin G4	Thr-D-Val-HMPro-Sar-MeVal	Thr-D-Val-Pro-Sar-MeAla
Actinomycin G5	Thr-D-Val-HMPro-Sar-MeVal	cHThr-D-Val-Pro-Sar-MeAla
Actinomycin G6	Thr-D-Val-HMPro-Sar-MeVal	rHThr-D-Val-Pro-Sar-MeAla
(7) novel Y-type actinomycins
Actinomycin Y1	Thr-D-Val-HMPro-Sar-MeVal	ClThr-D-Val-OPro-Sar-MeAla
Actinomycin Y2	Thr-D-Val-HMPro-Sar-MeVal	ClThr-D-Val-Hyp-Sar-MeAla
Actinomycin Y3	Thr-D-Val-HMPro-Sar-MeVal	rHThr-D-Val-OPro-Sar-MeAla
Actinomycin Y4	Thr-D-Val-HMPro-Sar-MeVal	rHThr-D-Val-Hyp-Sar-MeAla
Actinomycin Y5	Thr-D-Val-HMPro-Sar-MeVal	cThr-D-Val-OPro-Sar-MeAla
Actinomycin Y6 $(\mathbf{1})$	Thr-D-Val-HMPro-Sar-MeVal	crThr-D-Val-OPro-Sar-MeAla
Actinomycin Y7 $(\mathbf{2})$	Thr-D-Val-HMPro-Sar-MeVal	HThr-D-Val-OPro-Sar-MeAla
Actinomycin Y8 $(\mathbf{3})$	Thr-D-Val-HMPro-Sar-MeVal	Thr-D-Val-OPro-Sar-MeAla
Actinomycin Y9 $(\mathbf{4})$	Thr-D-Val-MPro-Sar-MeVal	Thr-D-Val- OPro -Sar-MeAla

Differences to actinomycin D are shown in bold letters. All amino acids are L-configuration except when indicated otherwise. Abbreviations: MeVal=N-methylvaline, MeAla=N-methyl-L-alanine, aIle=allo-isoleucine, Sar=sarcosine, MPro=cis-5-methylproline, HMPro=trans-3-hydroxy-cis-5-methylproline, Hyp=trans-4-hydroxyproline, OPro=4- oxoproline, MOPro=cis-5-methyl-4-oxoproline, aHyp=cis-4-hydroxyproline, HThr=4-hydroxythreonine, ClThr=4-chlorothreonine, cThr/cHThr=cyclic Thr or HThr, i.e. forming an additional ring closure to the chromophore, rHThr= rearrangement of the HThr (β-ring) connectivity.

^aThis table was updated based on previous overview on naturally occurring actinomycins (ref. 3).

^bThe numbers in red indicated compounds identified in this study