Peptide name : Temporin-1RNb

Source/Organism : The black-spotted frog, Northeastern China, Asia

Linear/Cyclic : Not found

Chirality : Not found

Peptide length: 12

C-terminal modification: Not found

N-terminal modification : Amidation

Non-natural peptide information: None

Assay type : Cytotoxicity assay, MTT/MTS assay

Assay time : 18–24h

Activity : IC50 : 11.4 ± 2.3 µM

Cell line : MCF 7

Cancer type : Breast cancer

Other activity : Anti-bacterial activity; Hemolytic activity

Amino acid composition bar chart :

Molecular mass : 1444.8477 Dalton

Aliphatic index : 1.625

Instability index : 27.1167

Hydrophobicity (GRAVY) : 0.8583

Isoelectric point : 11.166

Charge (pH 7) : 2.7581

Aromaticity : 0.166

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

Hydrophobic/hydrophilic ratio : 3

hydrophobic moment : 0.3777

Missing amino acid : C,W,H,Q,T,M,I,E,S,D,Y,N,A,V

Most occurring amino acid : L

Most occurring amino acid frequency : 5

Least occurring amino acid : P

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (0.5, 0.1, 0.5)

SMILES Notation: CC(C)C[C@H](NC(=O)[C@H](CC(C)C)NC(=O)CNC(=O)[C@H](Cc1ccccc1)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CCCCN)NC(=O)[C@H](CCCCN)NC(=O)[C@H](CC(C)C)NC(=O)[C@@H]1CCCN1C(=O)[C@H](CC(C)C)NC(=O)[C@@H](N)Cc1ccccc1)C(=O)O

1 : Li A, et al. Purification, molecular cloning, and antimicrobial activity of peptides from the skin secretion of the black-spotted frog, Rana nigromaculata. World J Microbiol Biotechnol. 2013; 29:1941-9. doi: 10.1007/s11274-013-1360-y

Paper title : Purification, molecular cloning, and antimicrobial activity of peptides from the skin secretion of the black-spotted frog, Rana nigromaculata.

Doi : https://doi.org/10.1007/s11274-013-1360-y

Abstract : Antimicrobial peptides from a wide range of amphibian species, especially frogs of the genus Rana, have been characterised and are potential therapeutic agents. Here we describe the isolation, purification, and structural and biological characterisation of three novel antimicrobial peptides from the skin secretions of the black spotted frog, Rana nigromaculata, from Northeastern China. The peptides were identified as belonging to two known families: the temporin, which was first identified in R. nigromaculata from China, and the brevinin-2. Temporin-1RNa and temporin-1RNb both containing three positive charges and have a high potency against microorganisms (MIC: 3.13-8.3 μM against Gram-positive bacteria, 12.5-25.0 μM against Gram-negative bacteria, and 6.25-12.5 μM against Candida albicans) and a high haemolytic activity against human erythrocytes (HC50: 100-150 μM). Brevinin-2RNa contains a single intra-disulphide bridge at the C-terminus that is active towards the tested Gram-positive bacteria but is not active against E. coli and P. aeruginosa. The cDNAs encoding three novel peptide precursors were also subsequently cloned from an R. nigromaculata skin cDNA library and sequenced. The precursors contain 58-72 amino acid residues, which include a conserved signal peptide, acidic propeptide, and the mature temporin-1RNa, temporin-1RNb and brevinin-2RNa. The CD spectra of temporin-1RNa and temporin-1RNb in water, 30 mM SDS and 50 % trifluoroethanol (TFE) indicated that both peptides adopted an aperiodic structure in water and an organised structure with an α-helical conformation in TFE and SDS solution. The conformational transition induced by TFE or SDS reflects the potential ability of temporin-1RNa and temporin-1RNb to interact with anionic membranes.