LAUSR

Antimicrobial peptides (AMPs) play a crucial role in the innate immune system of all living organisms, protecting them from the infections caused by pathogens [1]. AMPs exhibit various biological activities, including antibacterial, antifungal, antiviral, anti-parasitic, anticancer, and immunoregulatory activity [2]. Most cationic AMPs exert broad-spectrum antibacterial activity by interacting with negatively charged lipid membrane of bacteria through the electrostatic electricity. In comparison with normal cells, the increase of phosphatidylserine on the membrane of cancer cells contributes to more negative charges [3], which makes cationic AMPs promising alternative candidates for anti-tumor reagents. Furthermore, AMPs are less toxic to normal cells, and tumor cells are not likely to develop drug resistance against AMPs [4]. In our previous study, we cloned 14 antimicrobial peptides, including temporin-GHa (GHa) and GHb, from the skin of Hylarana guentheri frogs and identified their broad-spectrum antimicrobial activities [5]. The helical wheel projection and predicted structure show that GHa and GHb have a typical amphiphilic α -helix. Sec-ondary structure analyses by circular dichroism (CD) demonstrate that both are mainly in irregular coil structure in saline solution, and predominantly in helix in sodium dodecyl sulfonate (SDS, simu-lating the bacterial cell membrane) and