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.:4.2 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.:4.2
- 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).:3 Hybrid ACPs based on Cecropin A have been studied for anticancer properties.:7.1
- Cecropins at the US National Library of Medicine Medical Subject Headings (MeSH)
- Lauwers A, Twyffels L, Soin R, Wauquier C, Kruys V, Gueydan C (January 2009), "Post-transcriptional regulation of genes encoding anti-microbial peptides in Drosophila", J. Biol. Chem., 284 (13): 8973–83, PMC , PMID 19176529, doi:10.1074/jbc.M806778200.
- Boman HG, Hultmark D (1987), "Cell-free immunity in insects", Annu. Rev. Microbiol., 41: 103–126, PMID 3318666, doi:10.1146/annurev.mi.41.100187.000535.
- Boman HG (1991), "Antibacterial peptides: key components needed in immunity", Cell, 65 (2): 205–207, PMID 2015623, doi:10.1016/0092-8674(91)90154-Q.
- Boman HG, Faye I, Lee JY, Gudmundsson GH, Lidholm DA (1991), "Cell-free immunity in Cecropia. A model system for antibacterial proteins", Eur. J. Biochem., 201 (1): 23–31, PMID 1915368, doi:10.1111/j.1432-1033.1991.tb16252.x.
- Hoskin, D.W.; Ramamoorthy, A. (February 2008), "Studies on anticancer activities of antimicrobial peptides", Biochimica et Biophysica Acta (BBA) - Biomembranes, 1778 (2): 357–375, PMC , PMID 18078805, doi:10.1016/j.bbamem.2007.11.008
- Loraine Susan Silvestro, "Function and structure of cecropin A" (January 1, 2000). Dissertations available from ProQuest. Paper AAI9965567. http://repository.upenn.edu/dissertations/AAI9965567
- cecropin family OPM
- Protein Data Bank (1930), Solution structure of CB1a, a novel anticancer peptide derived from natural antimicrobial peptide cecropin B [<http://www.rcsb.org/pdb/explore/explore.do?structureId=2IGR> <Protein Data Bank>]
- Hoskin 2008 (above) section 4.2
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