Peptide name : PTP-7b

Source/Organism : Synthetic peptide

Linear/Cyclic : Linear

Chirality : L

Peptide length: 13

C-terminal modification: Linear

N-terminal modification : Free

Non-natural peptide information: None

Assay type : MTT/MTS assay

Assay time : Not found

Activity : IC50 : 32 µM

Cell line : A-549

Cancer type : Lung cancer

Other activity : Anti-microbial activity

Amino acid composition bar chart :

Molecular mass : 1429.7469 Dalton

Aliphatic index : 1.653

Instability index : -8.8615

Hydrophobicity (GRAVY) : 1.5308

Isoelectric point : 8.7572

Charge (pH 7) : 0.8463

Aromaticity : 0.153

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

Hydrophobic/hydrophilic ratio : 3.33333333

hydrophobic moment : 0.7999

Missing amino acid : C,R,W,Q,T,P,M,I,E,D,Y,N,V

Most occurring amino acid : L

Most occurring amino acid frequency : 5

Least occurring amino acid : G

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (0.6, 0.1, 0.5)

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

1 : Chen L, et al. Peptide self-assembly on cell membranes to induce cell lysis. Biomacromolecules. 2012; 13:3327-33. doi: 10.1021/bm301106p

Paper title : Peptide self-assembly on cell membranes to induce cell lysis.

Doi : https://doi.org/10.1021/bm301106p

Abstract : Self-assembling into aggregates with defined structures is a common phenomenon for many peptides at high concentrations. In this study, we found that when PTP-7b (FLGALFKALSHLL), a concentration-dependent self-assembling peptide, bound to tissue cells and accumulated on cell surfaces, it migrated and self-assembled into exosome-like aggregates at certain locations on the cell membranes. Studies using confocal microscopy and scanning electron microscopy revealed that peptide PTP-7b induced cell tissue damage through a new cell lysis mechanism that involved peptide self-assembly on cell surfaces, extracting lipids from cell membranes, and transporting peptides into the cytoplasm. Peptide self-assembly attributed greatly to peptide-cell interactions and thus the biological activity of a peptide. Because peptide self-assembly was a slow process, PTP-7b-induced cell lysis showed a biphasic behavior: a gradual viability decrease was followed by a rapid decline. These results suggest that peptide self-assembly could be equally as important as charge and secondary structure of a peptide in determining the anticancer and antibacterial activities of therapeutic peptides.