Peptide name : NKL-MUT

Source/Organism : Trematomus bernacchii

Linear/Cyclic : Linear

Chirality : L

Peptide length: 27

C-terminal modification: Linear

N-terminal modification : Free

Non-natural peptide information:

Assay type : luciferase-based ATPlite assay

Assay time : 12-h

Activity : ATP level = 0.023 ± 0.007 at 40 μM

Cell line : B16-F10

Cancer type : Skin Cancer

Other activity : Antimicrobial

Amino acid composition bar chart :

Molecular mass : 3037.7964 Dalton

Aliphatic index : 1.263

Instability index : 1.6111

Hydrophobicity (GRAVY) : 0.1148

Isoelectric point : 11.471

Charge (pH 7) : 7.8403

Aromaticity : 3.703

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

Hydrophobic/hydrophilic ratio : 1.0769

hydrophobic moment : 0.0914

Missing amino acid : C,D,E,P,Q,T,W,Y

Most occurring amino acid : K

Most occurring amino acid frequency : 7

Least occurring amino acid : M

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (55., 18., 37.)

SMILES Notation: CC[C@H](C)[C@H](NC(=O)[C@H](CCCCN)NC(=O)[C@H](CC(N)=O)NC(=O)[C@H](C)NC(=O)[C@@H](NC(=O)[C@@H](NC(=O)[C@H](CCSC)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CCCCN)NC(=O)[C@H](CO)NC(=O)[C@H](CCCCN)NC(=O)[C@H](CC(C)C)NC(=O)[C@@H](N)CCCCN)C(C)C)C(C)C)C(=O)NCC(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CO)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](C)C(=O)N[C@@H](CCCNC(=N)N)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](Cc1ccccc1)C(=O)N[C@H](C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CO)C(=O)N[C@@H](Cc1c[nH]cn1)C(=O)O)C(C)C

1 : Buonocore F, et al. Antibacterial and anticancer activity of two NK-lysin-derived peptides from the Antarctic teleost Trematomus bernacchii. Fish Shellfish Immunol. 2023; 142:109099. doi: 10.1016/j.fsi.2023.109099

Paper title : Antibacterial and anticancer activity of two NK-lysin-derived peptides from the Antarctic teleost Trematomus bernacchii.

Doi : https://doi.org/10.1016/j.fsi.2023.109099

Abstract : The NK-lysin antimicrobial peptide, first identified in mammals, possesses both antibacterial and cytotoxic activity against cancer cell lines. Homologue peptides isolated from different fish species have been examined for their functional characteristics in the last few years. In this study, a NK-lysin transcript was identified in silico from the head kidney transcriptome of the Antarctic teleost Trematomus bernacchii. The corresponding amino acid sequence, slightly longer than NK-lysins of other fish species, contains six cysteine residues that in mammalian counterparts form three disulphide bridges. Real time-PCR analysis indicated its predominant expression in T. bernacchii immune-related organs and tissues, with greatest mRNA abundance detected in gills and spleen. Instead of focusing on the full T. bernacchii derived NK-lysin mature molecule, we selected a 27 amino acid residue peptide (named NKL-WT), corresponding to the potent antibiotic NK-2 sequence found in human NK-lysin. Moreover, we designed a mutant peptide (named NKL-MUT) in which two alanine residues substitute the two cysteines found in the NKL-WT. The two peptides were obtained by solid phase organic synthesis to investigate their functional features. NKL-WT and NKL-MUT displayed antibacterial activity against the human pathogenic bacterium Enterococcus faecalis and the ESKAPE pathogen Acinetobacter baumannii, respectively. Moreover, at the determined Minimum Inhibitory Concentration and Minimum Bactericidal Concentration values against these pathogens, both peptides showed high selectivity as they did not exhibit any haemolytic activity on erythrocytes or cytotoxic activity against mammalian primary cell lines. Finally, the NKL-MUT selectively triggers the killing of the melanoma cell line B16F10 by means of a pro-apoptotic pathway at a concentration range in which no effects were found in normal mammalian cell lines. In conclusion, the two peptides could be considered as promising candidates in the fight against antibiotic resistance and tumour proliferative action, and also be used as innovative adjuvants, either to decrease chemotherapy side effects or to enhance anticancer drug activity.