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siamycin I   Click here for help

GtoPdb Ligand ID: 14232

Synonyms: Siamycin-I
Compound class: Peptide
Comment: Siamycin I is an antimicrobial lasso peptide produced by Streptomyces sp. AA6532 and originally isolated from soil samples [5]. Siamycin I exhibits both antibacterial activity against Gram-positive bacteria [2] and antiviral activity against the HIV virus, interacting with HIV-1 envelope glycoprotein 160 (gp160) which is essential for fusion of the viral envelope with the host cell membrane [3].
2D Structure
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2D Structure

An image of the ligand's 2D structure. For small molecules with SMILES these are drawn using the NCI/CADD Chemical Identifier Resolver. Click on the image to access the chemical structure search tool with the ligand pre-loaded in the structure editor. For other types of ligands, e.g. longer nucleotides and peptides, a manually drawn representation of the molecule may be provided.

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SMILES / InChI / InChIKey
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SMILES / InChI / InChIKey

SMILES (Simplified Molecular Input Line Entry Specification) A specification for unambiguously describing the structure of chemical molecules using short ASCII strings. Canonical SMILES specify a unique representation of the 2D structure without chiral or isotopic specifications. Isomeric SMILES include chiral specification and isotopes.

Standard InChI (IUPAC International Chemical Identifier) and InChIKey InChI is a non-proprietary, standard, textual identifier for chemical substances designed to facilitate linking of information and database searching. An InChIKey is a simplified version of a full InChI, designed for easier web searching.

Generated using the Chemistry Development Kit (CDK) (Willighagen EL et al. Journal of Cheminformatics vol. 9:33. 2017, doi:10.1186/s13321-017-0220-4; https://cdk.github.io/)

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Canonical SMILES CC[C@H](C)[C@H]1C(=O)N[C@@H](C(C)C)C(=O)N[C@@H](CSSC[C@H]2C(=O)N[C@@H](CC(=O)N)C(=O)N[C@H]3CC(=O)N[C@@H](CSSC[C@@H](C(=O)NCC(=O)N[C@@H](CC4=CC=C(C=C4)O)C(=O)N[C@@H](C)C(=O)N1)NC(=O)CNC(=O)[C@H](C)NC(=O)[C@H](CC5=CC=CC=C5)NC3=O)C(=O)N[C@@H](CC(C)C)C(=O)NCC(=O)N[C@@H](C(C)C)C(=O)NCC(=O)N[C@@H](CO)C(=O)N2)C(=O)N[C@@H](CC6=CC=CC=C6)C(=O)N[C@@H](CC7=CNC8=C7C=CC=C8)C(=O)O
Isomeric SMILES CC[C@H](C)[C@H]1C(=O)N[C@H](C(=O)N[C@@H](CSSC[C@H]2C(=O)N[C@H](C(=O)N[C@H]3CC(=O)N[C@@H](CSSC[C@@H](C(=O)NCC(=O)N[C@H](C(=O)N[C@H](C(=O)N1)C)CC4=CC=C(C=C4)O)NC(=O)CNC(=O)[C@@H](NC(=O)[C@@H](NC3=O)CC5=CC=CC=C5)C)C(=O)N[C@H](C(=O)NCC(=O)N[C@H](C(=O)NCC(=O)N[C@H](C(=O)N2)CO)C(C)C)CC(C)C)CC(=O)N)C(=O)N[C@@H](CC6=CC=CC=C6)C(=O)N[C@@H](CC7=CNC8=CC=CC=C87)C(=O)O)C(C)C
InChI InChI=1S/C97H131N23O26S4/c1-11-50(8)80-96(144)119-79(49(6)7)95(143)117-71(93(141)112-63(32-54-22-16-13-17-23-54)87(135)115-66(97(145)146)34-56-37-99-59-25-19-18-24-58(56)59)46-150-149-45-70-92(140)113-64(35-72(98)123)88(136)114-65-36-73(124)108-69(91(139)110-60(30-47(2)3)83(131)101-41-77(128)118-78(48(4)5)94(142)103-40-75(126)107-67(42-121)90(138)116-70)44-148-147-43-68(109-76(127)38-100-81(129)51(9)104-86(134)62(111-89(65)137)31-53-20-14-12-15-21-53)84(132)102-39-74(125)106-61(33-55-26-28-57(122)29-27-55)85(133)105-52(10)82(130)120-80/h12-29,37,47-52,60-71,78-80,99,121-122H,11,30-36,38-46H2,1-10H3,(H2,98,123)(H,100,129)(H,101,131)(H,102,132)(H,103,142)(H,104,134)(H,105,133)(H,106,125)(H,107,126)(H,108,124)(H,109,127)(H,110,139)(H,111,137)(H,112,141)(H,113,140)(H,114,136)(H,115,135)(H,116,138)(H,117,143)(H,118,128)(H,119,144)(H,120,130)(H,145,146)/t50-,51-,52-,60-,61-,62-,63-,64-,65-,66-,67-,68-,69-,70-,71-,78-,79-,80-/m0/s1
InChI Key TXYRKTDGDMHVHR-NEKRQKPVSA-N

Generated using the Chemistry Development Kit (CDK) (Willighagen EL et al. Journal of Cheminformatics vol. 9:33. 2017, doi:10.1186/s13321-017-0220-4; https://cdk.github.io/)
References
1. Boudrioua A, Baëtz B, Desmadril S, Goulard C, Groo AC, Lombard C, Gueulle S, Marugan M, Malzert-Fréon A, Hartke A et al.. (2025)
Lasso peptides sviceucin and siamycin I exhibit anti-virulence activity and restore vancomycin effectiveness in vancomycin-resistant pathogens.
iScience, 28 (3): 111922. [PMID:40034853]
2. Daniel-Ivad M, Hameed N, Tan S, Dhanjal R, Socko D, Pak P, Gverzdys T, Elliot MA, Nodwell JR. (2017)
An Engineered Allele of afsQ1 Facilitates the Discovery and Investigation of Cryptic Natural Products.
ACS Chem Biol, 12 (3): 628-634. [PMID:28075554]
3. Lin PF, Samanta H, Bechtold CM, Deminie CA, Patick AK, Alam M, Riccardi K, Rose RE, White RJ, Colonno RJ. (1996)
Characterization of siamycin I, a human immunodeficiency virus fusion inhibitor.
Antimicrob Agents Chemother, 40 (1): 133-8. [PMID:8787894]
4. Tan S, Ludwig KC, Müller A, Schneider T, Nodwell JR. (2019)
The Lasso Peptide Siamycin-I Targets Lipid II at the Gram-Positive Cell Surface.
ACS Chem Biol, 14 (5): 966-974. [PMID:31026131]
5. Tsunakawa M, Hu SL, Hoshino Y, Detlefson DJ, Hill SE, Furumai T, White RJ, Nishio M, Kawano K, Yamamoto S et al.. (1995)
Siamycins I and II, new anti-HIV peptides: I. Fermentation, isolation, biological activity and initial characterization.
J Antibiot (Tokyo), 48 (5): 433-4. [PMID:7797448]