Peptide name : Frenatin 2.1S

Source/Organism : Skin secretions, the Orinoco lime frog, north central Guyana, South America

Linear/Cyclic : Not found

Chirality : Not found

Peptide length: 16

C-terminal modification: Not found

N-terminal modification : Amidation

Non-natural peptide information: None

Assay type : Cytotoxicity assay, Cell Titer-Glo Luminescent Cell Viability assay

Assay time : 24h

Activity : LC50 : 80 ± 6 μM

Cell line : A549

Cancer type : Lung adenocarcinoma

Other activity : Anti-bacterial activity

Amino acid composition bar chart :

Molecular mass : 1518.8418 Dalton

Aliphatic index : 1.706

Instability index : 32.9562

Hydrophobicity (GRAVY) : 1.275

Isoelectric point : 8.7572

Charge (pH 7) : 0.8463

Aromaticity : 0

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

Hydrophobic/hydrophilic ratio : 4.33333333

hydrophobic moment : -1.334

Missing amino acid : C,R,W,Q,P,M,E,F,S,D,Y,N

Most occurring amino acid : G

Most occurring amino acid frequency : 5

Least occurring amino acid : V

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](C)NC(=O)[C@H](CCCCN)NC(=O)CNC(=O)[C@@H](NC(=O)[C@H](Cc1c[nH]cn1)NC(=O)CNC(=O)[C@H](CC(C)C)NC(=O)[C@H](CC(C)C)NC(=O)[C@@H](NC(=O)CNC(=O)[C@@H](NC(=O)[C@H](CC(C)C)NC(=O)CN)C(C)C)[C@@H](C)O)[C@@H](C)CC)C(=O)N[C@@H](CC(C)C)C(=O)NCC(=O)O

1 : Conlon JM, et al. A family of antimicrobial and immunomodulatory peptides related to the frenatins from skin secretions of the Orinoco lime frog Sphaenorhynchus lacteus (Hylidae). Peptides. 2014; 56:132-40. doi: 10.1016/j.peptides.2014.03.020

Paper title : A family of antimicrobial and immunomodulatory peptides related to the frenatins from skin secretions of the Orinoco lime frog Sphaenorhynchus lacteus (Hylidae).

Doi : https://doi.org/10.1016/j.peptides.2014.03.020

Abstract : Peptidomic analysis of norepinephrine-stimulated skin secretions of the Orinoco lime tree frog Sphaenorhynchus lacteus (Hylidae, Hylinae) revealed the presence of three structurally related host-defense peptides with limited sequence similarity to frenatin 2 from Litoria infrafrenata (Hylidae, Pelodryadinae) and frenatin 2D from Discoglossus sardus (Alytidae). Frenatin 2.1S (GLVGTLLGHIGKAILG.NH2) and frenatin 2.2S (GLVGTLLGHIGKAILS.NH2) are C-terminally α-amidated but frenatin 2.3S (GLVGTLLGHIGKAILG) is not. Frenatin 2.1S and 2.2S show potent bactericidal activity against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MIC ≤16μM) but are less active against a range of Gram-negative bacteria. Frenatin 2.1S (LC50=80±6 μM) and 2.2S (LC50=75±5 μM) are cytotoxic against non-small cell lung adenocarcinoma A549 cells but are less hemolytic against human erythrocytes (LC50=167±8 μM for frenatin 2.1S and 169±7 μM for 2.2S). Weak antimicrobial and cytotoxic potencies of frenatin 2.3S demonstrate the importance of C-terminal α-amidation for activity. Frenatin 2.1S and 2.2S significantly (P<0.05) increased production of proinflammatory cytokines IL-1β and IL-23 by lipopolysaccharide (LPS)-stimulated mouse peritoneal macrophages and frenatin 2.1S also enhanced production of TNF-α. Effects on IL-6 production were not significant. Frenatin 2.2S significantly downregulated production of the anti-inflammatory cytokine IL-10 by LPS-stimulated cells. The data support speculation that frenatins act on skin macrophages to produce a cytokine-mediated stimulation of the adaptive immune system in response to invasion by microorganisms. They may represent a template for the design of peptides with therapeutic applications as immunostimulatory agents.