Peptide name : IL-1

Source/Organism : Synthetic

Linear/Cyclic : Linear

Chirality : L

Peptide length: 16

C-terminal modification: Linear

N-terminal modification : Free

Non-natural peptide information:

Assay type : MTT assay

Assay time : 4-h

Activity : IC50 = 73.9 ± 13.6 μM

Cell line : HeLa

Cancer type : Cervical Cancer

Other activity : Anticancer

Amino acid composition bar chart :

Molecular mass : 1835.2415 Dalton

Aliphatic index : 1.1

Instability index : 39.3438

Hydrophobicity (GRAVY) : 0.4

Isoelectric point : 11.263

Charge (pH 7) : 3.7571

Aromaticity : 18.75

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

Hydrophobic/hydrophilic ratio : 2.2

hydrophobic moment : -0.896

Missing amino acid : C,D,E,H,M,N,P,Q,T,V,Y

Most occurring amino acid : K

Most occurring amino acid frequency : 3

Least occurring amino acid : I

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (50, 18., 43.)

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

1 : Fan R, et al. Isoleucine/leucine residues at "a" and "d" positions of a heptad repeat sequence are crucial for the cytolytic activity of a short anticancer lytic peptide. Amino Acids. 2017; 49:193-202. doi: 10.1007/s00726-016-2350-9

Paper title : Isoleucine/leucine residues at "a" and "d" positions of a heptad repeat sequence are crucial for the cytolytic activity of a short anticancer lytic peptide.

Doi : https://doi.org/10.1007/s00726-016-2350-9

Abstract : Many lytic peptides contain a heptad sequence with leucine or isoleucine residues at "a" and "d" positions. However, their roles in the peptide-induced cytolytic process remain unclear. We have recently reported an anticancer lytic peptide ZXR-2 (FKIGGFIKKLWRSLLA), which contains a shortened zipper-like sequence with Ile/Leu at "a" and "d" positions. To understand the roles of these Ile/Leu residues, a series of analogs were constructed by sequentially replacing the Ile or Leu residue with alanine (Ala). Significant reduction of the cytolytic activity was observed when the Ile (3rd and 7th) and Leu (10th and 14th) residues at the "a" and "d" positions were substituted, while the replacement of the separate Leu (15th) residue had less effect. Based on the quenching of the intrinsic fluorescence of the peptides and their induced surface pressure changes of lipid monolayer, it was conjectured that the peptide ZXR-2 might insert into cell membranes from the C-terminal and to a depth of the W₁₁ position. Accordingly, I₃, I₇, and L₁₀ residues which mainly exposed in aqueous solution were more responsible for the peptide self-association on cell membranes, while L₁₄, together with L₁₅, might help peptide insert and anchor to cell membranes. These results are significant to elucidate the crucial roles of such Ile/Leu residues at "a" and "d" positions in peptide-peptide and peptide-membrane interactions to exert the membrane disruption activity of lytic peptides. With further understanding about the structure-activity relationship of lytic peptides, it would be helpful for designing novel anticancer lytic peptides.