Isolation and synthesis of falcitidin, a novel myxobacterial-derived
acyltetrapeptide with activity against the malaria target falcipain-2
Brinda Somanadhan1, Santosh R. Kotturi2, Chung Yan Leong1, Robert P. Glover1, Yicun Huang1,
Horst Flotow1, Antony D. Buss1, Martin J. Lear2, and Mark S. Butler1
1
MerLion Pharmaceuticals, 41 Science Park Road, The Gemini #04-03B, Singapore Science Park II,
Singapore 117610, Singapore
2
Department of Chemistry and Medicinal Chemistry Programme, National University of Singapore,
Singapore 117543, Singapore
Supporting information
S1. 7 day subculture of the Chitinophaga sp. Y23 in VY/2 agar media (page 2)
S2. Direct injection (+)-ESI-MS of falcitidin (1) with internal calibration to sodium formate (page 3)
S3. Direct injection (-)-ESI-MS of falcitidin (1) with internal calibration to sodium formate (page 4)
S4. 1H NMR spectrum (500 MHz) of falcitidin (1) in DMSO-d6 (page 5)
S5. 1H (300 MHz) and 13C NMR (75 MHz) of dipeptide 6 in DMSO-d6 (page 6)
S6. 1H (500 MHz) and 13C NMR (125 MHz) of tripeptide 7a in DMSO-d6 (page 7)
S7. 1H (300 MHz) and 13C NMR (75 MHz) of Fmoc–tetrapeptide 8 in CDCl3 (page 8)
S8. 1H (500 MHz) and 13C NMR (125 MHz) of tetrapeptide 9 in CDCl3 (page 9)
S9. 1H (300 MHz) and 13C NMR (75 MHz) of Trt-falcitidin (10) in CDCl3 (page 10)
S10. 1H (500 MHz) and 13C NMR (125 MHz) of synthetic falcitidin (1) in DMSO-d6 (page 11)
S11. 1H (500 MHz) and 13C NMR (125 MHz) of synthetic All-L 1b in DMSO-d6 (page 12)
S12. HPLC chromatograms of the Marfey-derivatized amino acids derived from derivatized L and D
amino acids, synthetic all-L 1b and the natural product falcitidin (1). (Page 13)
1
S1. 7 day subculture of the Chitinophaga sp. Y23 in VY/2 agar media
2
S2. Direct injection (+)-ESI-MS of falcitidin (1) with internal calibration to sodium formate
3
S3. Direct injection (-)-ESI-MS of falcitidin (1) with internal calibration to sodium formate
4
S4. 1H NMR spectrum (500 MHz) of falcitidin (1) in DMSO-d6
5
S5. 1H (300 MHz) and 13C NMR (75 MHz) of dipeptide 6 in DMSO-d6
6
S6. 1H (500 MHz) and 13C NMR (125 MHz) of tripeptide 7a in DMSO-d6
7
S7. 1H (300 MHz) and 13C NMR (75 MHz) of Fmoc-tetrapeptide 8 in CDCl3
8
S8. 1H (500 MHz) and 13C NMR (125 MHz) of tetrapeptide 9 in CDCl3
9
S9. 1H (300 MHz) and 13C NMR (75 MHz) of Trt-falcitidin (10) in CDCl3
10
S10. 1H (500 MHz) and 13C NMR (125 MHz) of synthetic falcitidin (1) in DMSO-d6
11
S11. 1H (500 MHz) and 13C NMR (125 MHz) of synthetic all-L 1b in DMSO-d6
L-Ile
12
L-Ile
D-Ile
21.755
20.459
s
D-Val
19.105
13.718
(a)
0.5
L-Val
17.070
17.265
17.623
FDAA
re
ih r
mAU(x1,000)
340nm,4nm (1.00)
1.0
L-Pro D-Pro
L-His
14.544
D-His
0.0
L-Val
L-Ile
20.692
L-Pro
L-His
2.5
22.5
19.416
(b)
20.0
min
L-Val-L-Ile
21.961
17.5
17.589
5.0
15.0
14.399
10.0
12.5
mAU(x1,000)
7.5 340nm,4nm (1.00)
0.0
12.5
15.0
17.5
20.0
22.5
L-Ile
20.265
20.553
20.0
min
L-Val-L-Ile
21.516
L-Val
19.009
L-Pro
17.638
16.992
D-His
0.0
10.0
17.5
13.083
(c)
1.0
15.0
16.254
10.0
12.5
mAU(x1,000)
340nm,4nm (1.00)
22.5
min
Figure S12. HPLC chromatograms of the Marfey-derivatized amino acids derived from derivatized L
and D amino acids, synthetic all-L 1b and the natural product falcitidin (1). (a) Derivatized L and D
amino acids of the constituent amino acids; (b) Derivatized amino acids of the hydrolyzed peptide
mixture of synthetic isovaleric acid-L-His-L-Ile-L-Val-L-Pro-NH2; (c) Derivatized amino acids of the
hydrolyzed peptide mixture of natural material, falcitidin (1).
The HPLC runs a (amino acid standards) and b (synthetic 1b) were run on the same day but c (natural
product 1) was run on a different day. The identity of the peaks was confirmed by co-injection and MS
as follows:
13