Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
2008678 | Peptides | 2005 | 8 Pages |
Abstract
Halocidin is an antimicrobial peptide, which is isolated from hemocytes from the tunicate, Halocynthia aurantium. In this study, we cloned the full-length cDNA of halocidin from pharyngeal tissue, using a combination of RT-PCR and 5â²-RACE-PCR. The observed cDNA structure indicated that halocidin is synthesized as a 10.37Â kDa prepropeptide. Based on the cDNA structure and the known amino acid sequence of the mature peptide, it was concluded that the precursor of halocidin contains a 21-residue signal peptide, followed by the 18 residues of the mature peptide, and a 56-residue anionic C-terminal extension, which is removed later on in the process. The signal sequence of halocidin exhibited a high degree of similarity with the corresponding portion of the Ci-META4 protein, which had been previously discovered in the coelomic cells of another tunicate, Ciona intestinalis, and is considered to play a role in metamorphosis. However, in several respects, the cDNA structure of Ci-META4 suggested that it might constitute a precursor for an antimicrobial peptide. Thus, we prepared a synthetic peptide, which was comprised of 19 N-terminal amino acid residues in the predicted mature region of Ci-META4, and tested it with regard to its antimicrobial activity. As a result, we confirmed that the synthetic peptide exhibited potent antimicrobial activity against Gram (+) and (â) bacteria, while evidencing no hemolytic activity toward human erythrocytes.
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Authors
Woong Sik Jang, Chong Han Kim, Min Sook Kang, Hee Jeong Chae, Seok Min Son, Sook Jae Seo, In Hee Lee,