Neha Patil


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Symbol  Cecropin
InterPro  IPR000875
SCOP  1f0d
Pfam  PF00272

Cecropins are antimicrobial peptides. They were first isolated from the hemolymph of Hyalophora cecropia, whence the term cecropin was derived. Cecropins lyse bacterial cell membranes; they also inhibit proline uptake and cause leaky membranes.


Cecropins constitute a main part of the cell-free immunity of insects. Cecropins are small proteins of about 31 - 37 amino acid residues active against both Gram-positive and Gram-negative bacteria. Cecropins isolated from insects other than Hyalophora cecropia (Cecropia moth) have been given various names; bactericidin, lepidopterin, sarcotoxin, etc. All of these peptides are structurally related.


Members include :

Cecropin A
Peptide Sequence (KWKLFKKIEKVGQNIRDGIIKAGPAVAVVGQATQIAK). Secondary structure includes two α helices. At low peptide to lipid ratios ion channels are formed, at high peptide to lipid ratios pores are formed.
Cecropin B
Peptide Sequence (KWKVFKKIEKMGRNIRNGIVKAGPAIAVLGEAKAL). Secondary structure includes two α helices.
from Aedes aegypti (Yellowfever mosquito).
(A lepidopteran) from Papilio xuthus an Asian swallowtail butterfly.
Cecropin P1
Peptide Sequence (SWLSKTAKKLENSAKKRISEGIAIAIQGGPR). An antibacterial peptide from Ascaris suum, a parasitic nematode that resides in the pig intestine, also belongs to this family.


A derivative of Cecropin B is an anticancer polypeptide(L). Structure consists of mainly alpha helixes, determined by solution NMR. Protein molecular weight = 4203.4g/mol.

Some of the cecropins (e.g. cecropin A, and cecropin B) have anticancer properties and are called anticancer peptides (ACPs). Hybrid ACPs based on Cecropin A have been studied for anticancer properties.


Cecropin Wikipedia

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