• • DRAMP ID

  • DRAMP00878

• • Peptide Name

  • Circulin-B (CIRB; Plant defensin)

• • Source

  • Chassalia parviflora

• • Family

  • Belongs to the cyclotide family

• • Gene

  • Not found

• • Sequence

  • GVIPCGESCVFIPCISTLLGCSCKNKVCYRN

• • Sequence Length

  • 31

• • UniProt Entry

  • P56879

• • Protein Existence

  • Protein level

• • Biological Activity

  • Antimicrobial, Antibacterial, Anti-Gram+, Anti-Gram-, Antiviral, Antifungal

• • Target Organism

  • • [Ref.10430870]Gram-positive bacterium: (L-salt): Staphylococcus aureus (MIC=13.5 µM).
    • Gram-negative bacteria: (L-salt, H-salt) (MIC µM): Escherichia coli (0.41, >500), Pseudomonas aeruginosa (25.5, 48), Proteus vulgaris (6.8, >500), Klebsiella oxytoca (8.2, 15.6).
    • Fungi (H-salt): Candida kefyr (MIC=29 µM).
    • NOTE: L-salt = Medium with 10 mM phosphate buffer; H-salt = L-salt supplemented with 100 mM NaCl.
    • [Ref.18008336]Virus:HIV:inhibition the cytopathic effects of HIV-1 infection in cultured human T-lymphoblast (CEM-SS) cells(EC50=40-260 nM).

• • Hemolytic Activity

  • • [Ref.10430870] EC50 = 550 μM against blood type A human erythrocytes.

• • Cytotoxicity

  • • [Ref.10430870] It caused 50% cell growth inhibition of mouse fibroblasts at 820 μM.
    • [Ref.18008336]CEM-SS cells:IC50=500 nM.

• • Binding Target

  • Not found

• • Linear/Cyclic

  • Cyclic

• • N-terminal Modification

  • Cyclization (N termini to C termini)

• • C-terminal Modification

  • Cyclization (C termini to N termini)

• • Nonterminal Modifications and Unusual Amino Acids

  • [Ref.8920961] There are three disulfide bonds between Cys5 and Cys19, Cys9 and Cys21, Cys14 and Cys27.

• • Stereochemistry

  • L

• • Structure

  • Beta strand (5 strands; 10 residues)

• • Structure Description

  • Cyclotides are mini-proteins derived from plants that have the characteristic features of a head-to-tail cyclised peptide backbone and a knotted arrangement of their three disulfide bonds.

• • Helical Wheel Diagram

  • 

• • PDB ID

  • 2ERI resolved by NMR.
• 2ERI-> 

• Predicted Structure

• There is no predicted structure for DRAMP00878.

DRAMP00878

• • Function

  • Probably participates in a plant defense mechanism. Has antibiotic activity. Inhibits the cytopathic effects and replication of the human immunodeficiency virus. Active against both Gram-positive and Gram-negative bacteria.

• • PTM

  • This is a cyclic peptide which contains three disulfide bonds 5-21; 9-23; 14-28.

• ·Literature 1

• • Title

  • An unusual structural motif of antimicrobial peptides containing end-to-end macrocycle and cystine-knot disulfides.

• • Pubmed ID

  • 10430870

• • Reference

  • Proc Natl Acad Sci U S A. 1999 Aug 3;96(16):8913-8918.

• • Author

  • Tam JP, Lu YA, Yang JL, Chiu KW.

• ·Literature 2

• • Title

  • Cyclotides as natural anti-HIV agents.

• • Pubmed ID

  • 18008336

• • Reference

  • Biopolymers. 2008;90(1):51-60.

• • Author

  • Ireland DC, Wang CK, Wilson JA, Gustafson KR, Craik DJ.

• ·Literature 3

• • Title

  • Analysis of the disulfide linkage pattern in circulin A and B, HIV-inhibitory macrocyclic peptides

• • Pubmed ID

  • 8920961

• • Reference

  • Biochem Biophys Res Commun. 1996 Nov 12;228(2):632-8. doi: 10.1006/bbrc.1996.1708.

• • Author

  • R Derua 1, K R Gustafson, L K Pannell