Isolation and characterization of gomesin, an 18-residue cysteine-rich defense peptide from the spider Acanthoscurria gomesiana hemocytes with sequence similarities to horseshoe crab antimicrobial peptides of the tachyplesinfamily

We have purified a small size antimicrobial peptide, named gomesin, from th e hemocytes of the unchallenged tarantula spider Acanthoscurria gomesiana, Gomesin has a molecular mass of 2270.4 Ha, with 18 amino acids, including a pyroglutamic acid as the N terminus, a C-terminal arginine Lu-amide, and f our cysteine residues forming two disulfide bridges, This peptide shows mar ked sequence similarities to antimicrobial peptides from other arthropods s uch as tachyplesin and polyphemusin from horseshoe crabs and androctonin fr om scorpions, Interestingly, it also shows sequence similarities to protegr ins, antimicrobial peptides from porcine leukocytes, Gomesin strongly affec ts bacterial growth, as well as the development of filamentous fungi and ye ast. In addition, we showed that gomesin affects the viability of the paras ite Leishmania amazonensis.