Peptide name : CA-MA2

Source/Organism : Ceropin-African clawed frog hybrid peptides

Linear/Cyclic : Linear

Chirality : L

Peptide length: 18

C-terminal modification: Linear

N-terminal modification : Amidation

Non-natural peptide information: None

Assay type : MTT/MTS assay

Assay time : 72h

Activity : IC50 : 25 µM

Cell line : A-549

Cancer type : Lung cancer

Other activity : Anti-microbial activity

Amino acid composition bar chart :

Molecular mass : 2274.8352 Dalton

Aliphatic index : 0.705

Instability index : -9.9389

Hydrophobicity (GRAVY) : -0.638

Isoelectric point : 10.778

Charge (pH 7) : 6.8403

Aromaticity : 0.222

Molar extinction coefficient (cysteine, cystine): (5500, 5500)

Hydrophobic/hydrophilic ratio : 1

hydrophobic moment : 1.424

Missing amino acid : C,R,Q,T,M,E,D,Y,N,V,G

Most occurring amino acid : K

Most occurring amino acid frequency : 7

Least occurring amino acid : W

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (0.5, 0.1, 0.3)

SMILES Notation: CC[C@H](C)[C@H](NC(=O)[C@H](CCCCN)NC(=O)[C@H](CCCCN)NC(=O)[C@H](Cc1ccccc1)NC(=O)[C@H](CC(C)C)NC(=O)[C@H](CCCCN)NC(=O)[C@H](Cc1c[nH]c2ccccc12)NC(=O)[C@@H](N)CCCCN)C(=O)N1CCC[C@H]1C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](Cc1ccccc1)C(=O)N[C@@H](CC(C)C)C(=O)N[C@@H](Cc1c[nH]cn1)C(=O)N[C@@H](CO)C(=O)N[C@@H](C)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](Cc1ccccc1)C(=O)O

1 : Shin SY, et al. Effects of the hinge region of cecropin A(1-8)-magainin 2(1-12), a synthetic antimicrobial peptide, on liposomes, bacterial and tumor cells. Biochim Biophys Acta. 2000; 1463:209-18. doi: 10.1016/s0005-2736(99)00210-2

Paper title : Effects of the hinge region of cecropin A(1-8)-magainin 2(1-12), a synthetic antimicrobial peptide, on liposomes, bacterial and tumor cells.

Doi : https://doi.org/10.1016/s0005-2736(99)00210-2

Abstract : A 20-residue hybrid peptide (CA(1-8)-MA(1-12): KWKLFKKIGIGKFLHSAKKF-NH(2)) incorporating 1-8 residues of cecropin A (CA) and 1-12 residues of magainin 2 (MA) has potent antibiotic activity without hemolytic activity. In order to investigate the effects of the flexible hinge sequence, Gly-Ile-Gly of CA(1-8)-MA(1-12) (CA-MA) on antibiotic activity, CA-MA and its three analogues, CA-MA1, CA-MA2 and CA-MA3 were synthesized. The Gly-Ile-Gly sequence of CA-MA was deleted in CA-MA1 and replaced with Pro and Gly-Pro-Gly in CA-MA2 and CA-MA3, respectively. CA-MA1 and CA-MA3 caused a significant decrease in the bactericidal rate against Escherichia coli and Bacillus subtilis and the tumoricidal activity against four different tumor cells, and the PC/PS (4:1, w/w) vesicle-aggregating and disrupting activities. However, CA-MA2 showed a similar bactericidal rate and antitumor, vesicle-aggregating and disrupting activities, as compared with CA-MA. These results suggested that the flexibility or beta-turn induced by Gly-Ile-Gly or Pro in the central part of CA-MA may be important in the electrostatic interaction of the cationic short alpha-helical region in the N-terminus with the cell membrane surface and the hydrophobic interaction of amphipathic alpha-helical region in the C-terminus with the hydrophobic acyl chains in the cell membrane. CA-MA3 exhibited lower activity in antibacterial, antitumor, and vesicle-aggregating and disrupting activities than CA-MA and CA-MA2. This result suggested that the excessive beta-turn structure by Gly-Pro-Gly in CA-MA3 seems to interrupt the ion channel/pore formation on the lipid bilayer. It was concluded that the appropriate flexibility or beta-turn structure provided by the central hinge is responsible for the effective antibiotic activity of the antimicrobial peptides with the helix-hinge-helix structure.