A novel 40-residue antimicrobial peptide, aurelin, exhibiting activity against Gram-positive and Gram-negative bacteria, was purified
from the mesoglea of a scyphoid jellyfish Aurelia aurita by preparative gel electrophoresis and RP-HPLC. Molecular mass
(4296.95 Da) and complete amino acid sequence of aurelin (AACSDRAHGHICESFKSFCKDSGRNGVKLRANCKKTCGLC)1
were determined. Aurelin has six cysteines forming three disulfide bonds. The total RNA was isolated from the jellyfish mesoglea,
RT-PCR and cloning were performed, and cDNA was sequenced. A 84-residue preproaurelin contains a putative signal peptide
(22 amino acids) and a propiece of the same size (22 amino acids). Aurelin has no structural homology with any previously identified
antimicrobial peptides but reveals partial similarity both with defensins and K+ channel-blocking toxins of sea anemones and belongs
to ShKT domain family.
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