Peptide name : Viphi E

Source/Organism : Chinese Violet herb

Linear/Cyclic : Not found

Chirality : L

Peptide length: 31

C-terminal modification: Not found

N-terminal modification : Free

Non-natural peptide information: None

Assay type : Not specified

Assay time : Not found

Activity : Not found

Cell line : Not found

Cancer type : Not found

Other activity : Immunomodulatory activity; Antihypertensive; Anti-microbial activity; Antiviral activity

Amino acid composition bar chart :

Molecular mass : 3182.7556 Dalton

Aliphatic index : 0.816

Instability index : 30.2355

Hydrophobicity (GRAVY) : 0.7161

Isoelectric point : 7.769

Charge (pH 7) : 0.7005

Aromaticity : 0.064

Molar extinction coefficient (cysteine, cystine): (1490, 1865)

Hydrophobic/hydrophilic ratio : 1.81818181

hydrophobic moment : -0.099

Missing amino acid : R,W,H,Q,T,M,D,L

Most occurring amino acid : C

Most occurring amino acid frequency : 6

Least occurring amino acid : E

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (0.1, 0.3, 0.2)

SMILES Notation: CC[C@H](C)[C@H](NC(=O)[C@H](CS)NC(=O)[C@@H]1CCCN1C(=O)[C@@H](NC(=O)[C@H](Cc1ccccc1)NC(=O)[C@@H](NC(=O)[C@H](CS)NC(=O)[C@H](CO)NC(=O)[C@H](CCC(=O)O)NC(=O)CNC(=O)[C@H](CS)NC(=O)[C@@H]1CCCN1C(=O)[C@@H](NC(=O)[C@H](CO)NC(=O)CN)[C@@H](C)CC)C(C)C)[C@@H](C)CC)C(=O)N[C@@H](CO)C(=O)N[C@@H](C)C(=O)N[C@H](C(=O)N[C@H](C(=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](CC(N)=O)C(=O)N[C@@H](CCCCN)C(=O)N[C@H](C(=O)N[C@@H](CS)C(=O)N[C@@H](Cc1ccc(O)cc1)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC(N)=O)C(=O)O)C(C)C)[C@@H](C)CC)C(C)C

1 : Wang G, et al. APD2: the updated antimicrobial peptide database and its application in peptide design. Nucleic Acids Res. 2009; 37:D933-7. doi: 10.1093/nar/gkn823

2 : He W, et al. Isolation and characterization of cytotoxic cyclotides from Viola philippica. Peptides. 2011; 32:1719-23. doi: 10.1016/j.peptides.2011.06.016

Paper title : APD2: the updated antimicrobial peptide database and its application in peptide design.

Doi : https://doi.org/10.1093/nar/gkn823

Abstract : The antimicrobial peptide database (APD, http://aps.unmc.edu/AP/main.php) has been updated and expanded. It now hosts 1228 entries with 65 anticancer, 76 antiviral (53 anti-HIV), 327 antifungal and 944 antibacterial peptides. The second version of our database (APD2) allows users to search peptide families (e.g. bacteriocins, cyclotides, or defensins), peptide sources (e.g. fish, frogs or chicken), post-translationally modified peptides (e.g. amidation, oxidation, lipidation, glycosylation or d-amino acids), and peptide binding targets (e.g. membranes, proteins, DNA/RNA, LPS or sugars). Statistical analyses reveal that the frequently used amino acid residues (>10%) are Ala and Gly in bacterial peptides, Cys and Gly in plant peptides, Ala, Gly and Lys in insect peptides, and Leu, Ala, Gly and Lys in amphibian peptides. Using frequently occurring residues, we demonstrate database-aided peptide design in different ways. Among the three peptides designed, GLK-19 showed a higher activity against Escherichia coli than human LL-37.

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

Doi : https://doi.org/10.1016/j.peptides.2011.06.016

Abstract : Cyclotides are a large family of plant peptides characterized by a macrocyclic backbone and knotted arrangement of three disulfide bonds. This unique structure renders cyclotides exceptionally stable to thermal, chemical and enzymatic treatments. They exhibit a variety of bioactivities, including uterotonic, anti-HIV, cytotoxic and hemolytic activity and it is these properties that make cyclotides an interesting peptide scaffold for drug design. In this study, eight new cyclotides (Viphi A-H), along with eight known cyclotides, were isolated from Viola philippica, a plant from the Violaceae family. In addition, Viba 17 and Mram 8 were isolated for the first time as peptides. The sequences of these cyclotides were elucidated primarily by using a strategy involving reduction, enzymatic digestion and tandem mass spectroscopy sequencing. Several of the cyclotides showed cytotoxic activities against the cancer cell lines MM96L, HeLa and BGC-823. The novel cyclotides reported here: (1) enhance the known sequence variation observed for cyclotides; (2) extend the number of species known to contain cyclotides; (3) provide interesting structure-activity relationships that delineate residues important for cytotoxic activity. In addition, this study provides insights into the potential active ingredients of traditional Chinese medicines.