DRAVP ID  DRAVPe02301

Peptide Name   Siamycin I

Sequence  CLGVGSCNDFAGCGYAVVCFW

Sequence Length  21

UniProt ID  No entry found

Taxon ID  None

Source  Streptomyces strain AA6532

Validation   Experimentally Validated

Gene Name/ID  Not Available

GenBank  Not Available

Amino Acid position  Not Available

Domain Accession ID  Not Available

Nucleotide sequence ID  Not Available

Molecular Type  Not Available

Chromosomal Position  Not Available

Target Organism  HIV-1,HIV-2

Assay  Antiviral Assay

Activity 

• [Ref:8787894]HIV-1 RF (CEM-SS, CPE XTT) ED₅₀ = 0.35 ± 0.26 mM, HIV-1 IIIB (CEM-SS, CPE XTT) ED₅₀ = 0.6 ± 0.10 mM, HIV-2 CBL-20 (CEM-SS, CPE XTT) ED₅₀ = 0.45 ± 0.25 mM, HIV RF (MT-2, p24) ED₅₀ = 0.05 ± 0.02 mM, HIV-1 NL4-3 (MT-2, p24) ED₅₀ = 0.26 ± 0.29 mM, HIV-1 Y181C/NL4-3 (MT-2, p24) ED₅₀ = 0.16 ± 0.09 mM, HIV-1 A71T/V82A/NL4-3 (MT-2, p24) ED₅₀ = 0.45 ± 0.22 mM, HIV-1 A018A (MT-2, p24) ED₅₀ = 0.89 ± 0.09 mM, HIV-1 A018C (MT-2, p24) ED₅₀ = 0.89 ± 0.12 mM, SIV mac 251 (MT-2, p24) ED₅₀ = 3.2 ± 0.48 mM, HIV-1 008-PRE-D4T SI (1) (PBMC, p24) ED₅₀ = 4.3 ± 1.9 mM, HIV-1 008-POST-D4T SI (111) (PBMC, p24) ED₅₀ = 5.7 ± 2.1 mM, HIV-1 002-PRE-D4T NSI (PBMC, p24) ED₅₀ = 3.6 ± 0.9 mM, HIV-1 002-POST-D4T SI (1/2) (PBMC, p24) ED₅₀ = 2.0 ± 1.1 mM.

Hemolytic Activity  No hemolysis information or data found in the reference(s) presented in this entry

Cytotoxicity  No cytotoxicity information found in the reference(s) presented

Binding Target  Not Found

Mechanism  Siamycin I acts as an HIV fusion inhibitor, specifically inhibiting the fusion between the HIV-1 gp160 envelope glycoprotein and CD4-expressing cells. It disrupts syncytium formation (fusion of infected cells with uninfected ones), which is a hallmark of HIV cytopathicity.In fusion assays, siamycin I at 0.08 µM reduced syncytium formation by 50% in a 4-hour coculture of HIV-1 RF-infected cells with uninfected T cells. It showed minimal effect on non-HIV fusion processes, indicating retrovirus-specific fusion inhibition.

PDB ID  None

Predicted Structure Download 

Linear/Cyclic  Cyclic

N-terminal Modification  Amidation

C-terminal Modification  Free

Other Modification   disulfide bonds link Cys1 with Cys13 and Cys7 with Cys19

Stereochemistry  L

Literature 1

Title   Siamycins I and II, new anti-HIV-1 peptides: II. Sequence analysis and structure determination of siamycin I

Pubmed ID   8557614

Reference   The Journal of antibiotics, 48(12), 1515–1517.

Author   Detlefsen, D. J., Hill, S. E., Volk, K. J., Klohr, S. E., Tsunakawa, M., Furumai, T., Lin, P. F., Nishio, M., Kawano, K., & Oki, T. (1995)

DOI   10.7164/antibiotics.48.1515