Effects of C-terminal amidation and heptapeptide ring on the biological activities and advanced structure of amurin-9KY, a novel antimicrobial peptide identified from the brown frog, Rana kunyuensis

作     者：Fen Zhang Zhi-Lai Guo Yan Chen Li Li Hai-Ning Yu Yi-Peng Wang 

作者机构：Department of Pharmaceutical SciencesCollege of Pharmaceutical SciencesSoochow UniversitySuzhou Jiangsu 215123China Department of Bioscience and BiotechnologyDalian University of TechnologyDalian Liaoning 116023China School of Life SciencesGuizhou Normal UniversityGuiyang Guizhou 550001China 

出 版 物：《Zoological Research》 (动物学研究（英文）)

年 卷 期：2019年第40卷第3期

页      面：198-204页

核心收录：

学科分类：0710[理学-生物学] 0830[工学-环境科学与工程（可授工学、理学、农学学位）] 07[理学] 0905[农学-畜牧学] 0906[农学-兽医学] 0833[工学-城乡规划学] 0713[理学-生态学] 0834[工学-风景园林学（可授工学、农学学位）] 

基　　金：supported by grants from the National Natural Science Foundation of China(31772455) Natural Science Foundation of Jiangsu Province(BK20160336and BK20171214) Natural Science Foundation of College in Jiangsu Province(16KJB350004) Suzhou Science and Technology Development Project(SYN201504 and SNG2017045) 

主　　题：Antimicrobial peptides Rana kunyuensis',Amurin-9KY Heptapeptide ring C-terminal amidation Structure activity relati on ship 

摘      要：Rana kunyuensis is a species of brown frog that lives exclusively on Kunyu Mountain,Yantai,China.In the current study,a 279-bp cDNA sequence encoding a novel antimicrobial peptide (AMP),designated as amurin-9KY,was cloned from synthesized double-strand skin cDNA of R.kunyuensis.The amurin-9KY precursor was composed of 62 amino acid (aa) residues,whereas the mature peptide was composed of 14 aa and contained two cysteines forming a C-terminal heptapeptide ring (Rana box domain) and an amidated C-terminus.These structural characters represent a novel amphibian AMP family.Although amurin-9KY exhibited high similarity to the already identified amurin-9AM from R.amurensis,little is known about the structures and activities of amurin-9 family AMPs so far.Therefore,amurin-9KY and its three derivatives (amurin-9KY1-3) were designed and synthesized.The structures and activities were examined to evaluate the influence of C-terminal amidation and the heptapeptide ring on the activities and structure of amurin-9KY..Results indicated that C-terminal amidation was essential for antimicrobial activity,whereas both C-terminal amidation and the heptapeptide ring played roles in the low hemolytic activity.Circular dichroism (CD) spectra showed that the four peptides adopted an α-helical conformation in THF/H2O (v/v 1∶1) solution,but a random coil in aqueous solution.Elimination of the C-terminal heptapeptide ring generated two free cysteine residues with unpaired thiol groups,which greatly increased the concentration-dependent anti-oxidant activity.Scanning electron microscopy (SEM) was also performed to determine the possible bactericidal mechanisms.