Cathelicidin-HR from Hoplobatrachus rugulosus: an antioxidant peptide that performs a protective effect against UV/H2O2 -induced DNA damage

Cathelicidins, a group of vertebrate multifunctional molecules, play a role in innate immunity. In this study, a cathelicidin was identified from the lungs of frogs, Hoplobatrachus rugulosus . A 474 base pairs complementary DNA sequence encoded a 157 amino acid residue prepropeptide of H. rugulosus cathelicidin (cathelicidin-HR), which consisting of a 20-residue signal peptide sequence, a 108-residue cathelin region, and a 29-residue cathelicidin-HR peptide. Amino acid sequence alignment and cladogram analysis illustrated that cathelicidin-HR have a high degree of similarity to other amphibian cathelicidins. The cathelicidin-HR peptide displays very low antimicrobial activity but exhibits dose-dependent antioxidant activity. Moreover, this peptide expresses DNA damage inhibition against UV/H 2 O 2 -induction. The molecular docking indicated that DNA damage protection of cathelicidin-HR might occur via DNA-peptide complex formation. This is the first amphibian cathelicidin peptide that possesses DNA damage inhibitory activity which might play a crucial role in oxidative stress.