Peptide name : Varv peptide E (Varv E; Plant defensin)

Source/Organism : Field pansy

Linear/Cyclic : Cyclic

Chirality : L

Peptide length: 29

C-terminal modification: Cyclic

N-terminal modification : Cyclization (C termini to N termini)

Non-natural peptide information: None

Assay type : SRB assay

Assay time : 24h

Activity : IC50 : > 10 µg/mL

Cell line : BEL-7402

Cancer type : Not found

Other activity : Hemolytic activity

Amino acid composition bar chart :

Molecular mass : 2916.337 Dalton

Aliphatic index : 0.469

Instability index : 39.9483

Hydrophobicity (GRAVY) : 0.1586

Isoelectric point : 5.9623

Charge (pH 7) : -0.2965

Aromaticity : 0.034

Molar extinction coefficient (cysteine, cystine): (5500, 5875)

Hydrophobic/hydrophilic ratio : 1.9

hydrophobic moment : 0.111

Missing amino acid : H,Q,M,K,F,D,Y,A

Most occurring amino acid : C

Most occurring amino acid frequency : 6

Least occurring amino acid : L

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (0.0, 0.4, 0.3)

SMILES Notation: CC[C@H](C)[C@H](NC(=O)[C@@H]1CCCN1C(=O)[C@H](CC(C)C)NC(=O)CN)C(=O)N[C@@H](CS)C(=O)NCC(=O)N[C@@H](CCC(=O)O)C(=O)N[C@H](C(=O)N[C@@H](CS)C(=O)N[C@H](C(=O)NCC(=O)NCC(=O)N[C@H](C(=O)N[C@@H](CS)C(=O)N[C@@H](CC(N)=O)C(=O)N[C@H](C(=O)N1CCC[C@H]1C(=O)NCC(=O)N[C@@H](CS)C(=O)N[C@@H](CO)C(=O)N[C@@H](CS)C(=O)N[C@@H](CO)C(=O)N[C@@H](Cc1c[nH]c2ccccc12)C(=O)N1CCC[C@H]1C(=O)N[C@H](C(=O)N[C@@H](CS)C(=O)N[C@H](C(=O)N[C@@H](CCCNC(=N)N)C(=O)N[C@@H](CC(N)=O)C(=O)O)[C@@H](C)O)C(C)C)[C@@H](C)O)[C@@H](C)O)C(C)C)[C@@H](C)O

1 : Tang J, et al. Isolation and characterization of cytotoxic cyclotides from Viola tricolor. Peptides. 2010; 31:1434-40. doi: 10.1016/j.peptides.2010.05.004

Paper title : Isolation and characterization of cytotoxic cyclotides from Viola tricolor.

Doi : https://doi.org/10.1016/j.peptides.2010.05.004

Abstract : Many plants of the Violaceae plant family have been used in traditional remedies, and these plants often contain cyclotides, a particular type of plant cyclopeptide that is distinguished by a cyclic cystine knot motif. In general, bioactive plant cyclopeptides are interesting candidates for drug development. In the current study, a suite of 14 cyclotides, which includes seven novel cyclotides [vitri B, C, D, E, F, varv Hm, and He], together with seven known cyclotides [varv A, D, E, F, H, vitri A, and cycloviolacin O2], was isolated from Viola tricolor, a common flower. A chromatography-based method was used to isolate the cyclotides, which were characterized using tandem mass spectrometry and NMR spectroscopy. Several of the cyclotides showed cytotoxic activities against five cancer cell lines, U251, MDA-MB-231, A549, DU145, and BEL-7402. Three cyclotides, vitri A, vitri F, and cycloviolacin O2, were the most cytotoxic. The cytotoxic activity of the cyclotides did not correlate well with their hemolytic activity, indicating that different interactions, most likely with membranes, are involved for cytotoxic and hemolytic activities. Homology modeling of the structures was used in deriving structure-activity relationships.