Peptide name : Citropin 1.1

Source/Organism : Blue mountains tree frog

Linear/Cyclic : Linear

Chirality : L

Peptide length: 16

C-terminal modification: Linear

N-terminal modification : Amidation

Non-natural peptide information: None

Assay type : Sulforhodamine B assay

Assay time : Not found

Activity : IC50 : 5 M

Cell line : Liver tumor celline

Cancer type : Liver cancer

Other activity : Anti-bacterial activity

Amino acid composition bar chart :

Molecular mass : 1615.9536 Dalton

Aliphatic index : 1.581

Instability index : 14.1875

Hydrophobicity (GRAVY) : 1.2813

Isoelectric point : 8.5909

Charge (pH 7) : 0.7592

Aromaticity : 0.062

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

Hydrophobic/hydrophilic ratio : 3

hydrophobic moment : -0.312

Missing amino acid : C,R,W,H,Q,T,P,M,E,Y,N

Most occurring amino acid : G

Most occurring amino acid frequency : 3

Least occurring amino acid : F

Least occurring amino acid frequency : 1

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

SMILES Notation: CC[C@H](C)[C@H](NC(=O)[C@@H](NC(=O)[C@H](CO)NC(=O)[C@H](C)NC(=O)[C@@H](NC(=O)[C@H](CCCCN)NC(=O)[C@H](CCCCN)NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@H](CC(=O)O)NC(=O)[C@H](Cc1ccccc1)NC(=O)[C@H](CC(C)C)NC(=O)CN)C(C)C)[C@@H](C)CC)C(C)C)C(C)C)C(=O)NCC(=O)NCC(=O)N[C@@H](CC(C)C)C(=O)O

1 : Doyle J, et al. nNOS inhibition, antimicrobial and anticancer activity of the amphibian skin peptide, citropin 1.1 and synthetic modifications. The solution structure of a modified citropin 1.1. Eur J Biochem. 2003; 270:1141-53. doi: 10.1046/j.1432-1033.2003.03462.x

Paper title : nNOS inhibition, antimicrobial and anticancer activity of the amphibian skin peptide, citropin 1.1 and synthetic modifications. The solution structure of a modified citropin 1.1.

Doi : https://doi.org/10.1046/j.1432-1033.2003.03462.x

Abstract : A large number of bioactive peptides have been isolated from amphibian skin secretions. These peptides have a variety of actions including antibiotic and anticancer activities and the inhibition of neuronal nitric oxide synthase. We have investigated the structure-activity relationship of citropin 1.1, a broad-spectrum antibiotic and anticancer agent that also causes inhibition of neuronal nitric oxide synthase, by making a number of synthetically modified analogues. Citropin 1.1 has been shown previously to form an amphipathic alpha-helix in aqueous trifluoroethanol. The results of the structure-activity studies indicate the terminal residues are important for bacterial activity and increasing the overall positive charge, while maintaining an amphipathic distribution of residues, increases activity against Gram-negative organisms. Anticancer activity generally mirrors antibiotic activity suggesting a common mechanism of action. The N-terminal residues are important for inhibition of neuronal nitric oxide synthase, as is an overall positive charge greater than three. The structure of one of the more active synthetic modifications (A4K14-citropin 1.1) was determined in aqueous trifluoroethanol, showing that this peptide also forms an amphipathic alpha-helix.