Peptide name : CPF-ST3

Source/Organism : Diploid clawed frog, Western clawed frog,Africa

Linear/Cyclic : Not found

Chirality : L

Peptide length: 18

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 : Skin cancer

Other activity : Anti-bacterial activity; Anti-fungal activity; Hemolytic activity

Amino acid composition bar chart :

Molecular mass : 1777.1989 Dalton

Aliphatic index : 1.788

Instability index : -9.4222

Hydrophobicity (GRAVY) : 1.1222

Isoelectric point : 10.002

Charge (pH 7) : 1.7581

Aromaticity : 0

Molar extinction coefficient (cysteine, cystine): (0, 0)

Hydrophobic/hydrophilic ratio : 3.5

hydrophobic moment : -1.516

Missing amino acid : C,R,W,H,Q,T,M,E,F,D,Y

Most occurring amino acid : L

Most occurring amino acid frequency : 6

Least occurring amino acid : P

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (0.5, 0.3, 0.4)

SMILES Notation: CC[C@H](C)[C@H](NC(=O)[C@H](CCCCN)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CC(C)C)NC(=O)[C@@H]1CCCN1C(=O)CNC(=O)[C@H](CC(C)C)NC(=O)[C@H](CC(C)C)NC(=O)CN)C(=O)N[C@@H](C)C(=O)N[C@@H](C)C(=O)N[C@@H](CCCCN)C(=O)N[C@H](C(=O)NCC(=O)N[C@@H](CO)C(=O)N[C@@H](CC(N)=O)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CC(C)C)C(=O)O)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 : Ali MF, et al. Antimicrobial peptides isolated from skin secretions of the diploid frog, Xenopus tropicalis (Pipidae). Biochim Biophys Acta. 2001; 1550:81-9. doi: 10.1016/s0167-4838(01)00272-2

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 : Antimicrobial peptides isolated from skin secretions of the diploid frog, Xenopus tropicalis (Pipidae).

Doi : https://doi.org/10.1016/s0167-4838(01)00272-2

Abstract : Seven peptides (XT-1-XT-7) with antimicrobial activity were isolated from norepinephrine-stimulated skin secretions of the diploid clawed frog, Xenopus tropicalis. Structural characterization of the peptides demonstrated that amino acid sequence similarity to antimicrobial peptides previously isolated from Xenopus laevis was low, suggesting that the species are not closely related phylogenetically. Peptides XT-5 and XT-3 are probably the orthologs of X. laevis peptide glycine-leucine amide (PGL(a)) and the N-terminal spacer region of prolevitide, respectively. XT-1, XT-6 and XT-7 show limited structural similarity to the spacer region of X. laevis procaeruleins and the paralogs XT-2 and XT-4 are similar to corresponding regions of proxenopsin. Orthologs of the magainins were not identified. The C-terminally alpha-amidated peptide XT-7 (GLLGPLLKIAAKVGSNLL.NH2) showed the lowest minimum inhibitory concentrations against reference microorganisms (Staphylococcus aureus 5 microM, Escherichia coli 5 microM, and Candida albicans 40 microM) and was also active against clinical isolates of methicillin-resistant S. aureus, Staphylococcus epidermidis, Staphylococcus saprophyticus, Streptococcus group C, Shigella sonnei, Pseudomonas aeruginosa and Enterobacter cloacae. The peptide was, however, hemolytic against human erythrocytes (50% lysis at 70 microM). Circular dichroism studies showed that XT-7 has a random structure in aqueous solution, pH 7.0 but adopts an alpha-helical conformation in the presence of 50% trifluoroethanol. Decreasing the cationicity of XT-7 either by replacement of the C-terminal CONH2 group by COOH or by deletion of the Lys(8) residue produced analogs with greatly (>10-fold) decreased antimicrobial potencies.