Cathelicidins, a group of vertebrate multifunctional molecules, play a role in innate immunity. Cathelicidins are antimicrobial peptides (AMPs) that are involved in protection against microbial invasion. Presently, cathelicidin peptides have been identified from only 14 amphibian species. In the study, a novel cathelicidin was identified from the lungs of frogs, Hoplobatrachus rugulosus. A 474 base pairs (bp) complementary DNA (cDNA) 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 peptide (PC29). Amino acid sequence alignment and cladogram analysis illustrated that cathelicidin-HR have a high degree of similarity to further amphibian cathelicidins. The PC29 peptide displays antimicrobial activity only against Bacillus subtilis and Enterococcus faecalis. However, the PC29 peptide performed dose-dependent antioxidant activity. This is the first cathelicidin antioxidant peptide identified from the lung which provided a template for the development of potent bi-functional peptide therapeutic agents.

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.

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 (bp) complementary DNA (cDNA) 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 further 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/H2O2-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.