Peptide name : Cecropin B

Source/Organism : Chinese oak silk moth

Linear/Cyclic : Linear

Chirality : Not found

Peptide length: 35

C-terminal modification: Linear

N-terminal modification : Not found

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 : 3817.6158 Dalton

Aliphatic index : 1.171

Instability index : 22.08

Hydrophobicity (GRAVY) : 0.0029

Isoelectric point : 10.729

Charge (pH 7) : 6.7587

Aromaticity : 0.057

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

Hydrophobic/hydrophilic ratio : 1.69230769

hydrophobic moment : 0.8564

Missing amino acid : C,H,Q,T,M,S,D,Y

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): (0.4, 0.2, 0.3)

SMILES Notation: CC[C@H](C)[C@H](NC(=O)CNC(=O)[C@H](CC(N)=O)NC(=O)[C@H](CCCNC(=N)N)NC(=O)[C@@H](NC(=O)[C@H](CC(N)=O)NC(=O)[C@H](CCCNC(=N)N)NC(=O)CNC(=O)[C@@H](NC(=O)[C@H](CCCCN)NC(=O)[C@H](CCC(=O)O)NC(=O)[C@@H](NC(=O)[C@H](CCCCN)NC(=O)[C@H](CCCCN)NC(=O)[C@H](Cc1ccccc1)NC(=O)[C@@H](NC(=O)[C@H](CCCCN)NC(=O)[C@H](Cc1c[nH]c2ccccc12)NC(=O)[C@@H](N)CCCCN)[C@@H](C)CC)[C@@H](C)CC)C(C)C)[C@@H](C)CC)C(=O)N[C@H](C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](C)C(=O)NCC(=O)N1CCC[C@H]1C(=O)N[C@@H](C)C(=O)N[C@H](C(=O)N[C@@H](C)C(=O)N[C@H](C(=O)N[C@@H](CC(C)C)C(=O)NCC(=O)N[C@@H](CCC(=O)O)C(=O)N[C@@H](C)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](C)C(=O)N[C@@H](CC(C)C)C(=O)O)C(C)C)C(C)C)[C@@H](C)CC

1 : Qu Z, et al. Insect immunity: isolation and structure of cecropins B and D from pupae of the Chinese oak silk moth, Antheraea pernyi. Eur J Biochem. 1982; 127:219-24. doi: 10.1111/j.1432-1033.1982.tb06858.x

Paper title : Insect immunity: isolation and structure of cecropins B and D from pupae of the Chinese oak silk moth, Antheraea pernyi.

Doi : https://doi.org/10.1111/j.1432-1033.1982.tb06858.x

Abstract : The immune system in the Chinese oak silk moth, Antheraea pernyi, has been compared with that of the Cecropia moth which has been characterized earlier. Antibacterial activity against Escherichia coli was induced in diapausing pupae by injection of viable E. coli or Enterobacter cloacae. The activity reached a maximum on day 7-8 after which the response gradually declined. The pupae produced a set of immune proteins with P4 and P5 as major labelled components similar to that earlier found in Cecropia. The major antibacterial factor in A. pernyi was cecropin D. A procedure is described for the isolation of cecropin B and D, which is in principle similar to the one used for the isolation of the corresponding cecropins from Cecropia pupae. Amino acid sequence analyses of the A. pernyi cecropins show the D form to contain 36 amino acid residues and that both cecropins have blocked C-termini. The general structure of cecropins having a charged N-terminal region (residues 1-21) followed by a long hydrophobic stretch (residues 22-32) is well conserved. Cecropin B and D from A. pernyi differ from the corresponding proteins in Cecropia by four and three conservative amino acid replacements, respectively. The homology between the cecropins from the two insects suggests that they orginate from a single ancestral gene. The antibacterial activity was tested against nine different bacterial species. Evolutionary aspects of the cecropins are discussed.