Peptide name : C18G

Source/Organism : Derivative of the carboxyl terminus of human platelet factor IV, animal-derived, natural derivative

Linear/Cyclic : Linear

Chirality : Not found

Peptide length: 18

C-terminal modification: Linear

N-terminal modification : Free

Non-natural peptide information: None

Assay type : Not specified

Assay time : Not found

Activity : Not found

Cell line : Not found

Cancer type : Not found

Other activity : Anti-bacterial activity

Amino acid composition bar chart :

Molecular mass : 2043.6246 Dalton

Aliphatic index : 1.411

Instability index : -14.138

Hydrophobicity (GRAVY) : -0.188

Isoelectric point : 10.477

Charge (pH 7) : 6.7879

Aromaticity : 0.055

Molar extinction coefficient (cysteine, cystine): (1490, 1490)

Hydrophobic/hydrophilic ratio : 1

hydrophobic moment : -1.552

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

Most occurring amino acid : K

Most occurring amino acid frequency : 7

Least occurring amino acid : Y

Least occurring amino acid frequency : 1

Secondary structure fraction (Helix, Turn, Sheet): (0.8, 0.1, 0.3)

SMILES Notation: CC(C)C[C@H](NC(=O)[C@H](C)N)C(=O)N[C@@H](Cc1ccc(O)cc1)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](CC(C)C)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](CC(C)C)C(=O)N[C@@H](CCCCN)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](CC(C)C)C(=O)NCC(=O)O

1 : Darveau RP, et al. Peptides related to the carboxyl terminus of human platelet factor IV with antibacterial activity. J Clin Invest. 1992; 90:447-55. doi: 10.1172/JCI115880

Paper title : Peptides related to the carboxyl terminus of human platelet factor IV with antibacterial activity.

Doi : https://doi.org/10.1172/JCI115880

Abstract : A peptide (C13) corresponding to the last 13 amino acids of the carboxyl terminus of human platelet factor IV was found to be antibacterial. Amino acid substitutions predicted to disrupt either the amphipathic or alpha-helical nature of C13 rendered the peptide inactive. Antibacterial activity was demonstrated in normal human serum on bacteria which had been previously exposed to low levels of cefepime, a beta-lactam antibiotic. Peptide analogues were examined for more potent antibacterial activity in an antibacterial assay that employed normal human serum and low levels of cefepime. A peptide analogue (C18G) with 80-fold more antibacterial activity than C13 was identified. Studies in C8-deficient sera confirmed an essential role of human serum complement for optimal antibacterial activity. Additional studies showed low levels of cefepime, although not essential, enhanced the antibacterial activity of C18G. Animal protection experiments demonstrated that either peptide C18G or an analogue with all D amino acids (C18X) significantly increased the survival of neutropenic mice when coadministered with a low level of cefepime. This work has resulted in the identification of a new group of antibacterial peptides.