中文摘要：

为了解牛蛙皮肤抗菌肽的多样性及结构特点,根据GenBank数据库中蛙属抗菌肽基因信号肽序列设计简并引物,以RT-PCR技术扩增牛蛙皮肤抗菌肽基因,克隆得到cDNA全长序列并进行测序和序列分析。用生物信息学软件分析其cDNA序列特点,预测成熟肽的理化性质。结果得到48个完整的cDNA序列,分别编码24种抗菌肽前体,它们均由信号肽、前导肽和成熟肽3部分组成。对序列测定结果的预测分析表明,牛蛙皮肤抗菌肽前体核苷酸序列与已报道的其他蛙类抗菌肽具有较高的同源性,同源性达到80%以上,但成熟肽的序列变异很大,具有物种特异性,其中6个为新的抗菌肽序列。牛蛙皮肤抗菌肽成熟肽的二级结构主要以α-螺旋和β-折叠为主,均为疏水性短肽。

英文摘要：

To analyze the diversity and construction features of the skin antibacterial peptides of Rana catesbeiana,the degenerate primers were designed based on the signal peptide of Rana antibacterial peptides and subjected to RT-PCR amplification of corresponding cDNAs from Rana catesbeiana mRNA.cDNAs were cloned and sequenced.Properties of matured peptides were predicted by using informatics software tools.48 complete cDNAs were found to encode 19 antimicrobial peptides precursor including the signal peptide,prodomain peptide and mature peptide.The predicted results indicated that the precursor antibacterial peptides of Rana catesbeiana were high homology（more than 80 percent） with the other Rana antibacterial peptides reported previously,but hypervariable mature peptides possessed the species specificity.In which 6 show little amino acid sequence similarity to previously reported antimicrobial peptides,which could be a new family of Rana antibacterial peptide.The mature antibacterial peptides of Rana catesbeiana are all hydrophobic short peptides and the secondary structure is mainly α-helix and beta structure.All the above information will contribute to the further investigation of the physiology and biochemistry character,medical activity and the genetic expression of antibacterial peptides of Rana catesbeiana.