杂合抗菌肽CecA_mil的改造及在毕赤酵母中的分泌表达

Modification of hybrid antimicrobial peptide CecA-mil gene and its over-secretion expression in Pichia pastoris

参照毕赤氏巴斯德酵母 (Pichiapastoris)偏好密码子 ,改造并化学合成杂合抗菌肽CecA_mil基因 ,改造后的CecA_mil基因克隆到pPICZα_A载体中 ,构建分泌型重组酵母表达载体pPICZα_A_CM ,转化Pichiapastoris受体菌X_33。在醇氧化酶 (AOX)启动子调控下 ,分子量约 1 9kD的CecA_mil杂合抗菌肽获得表达 ,经表达条件优化 ,重组酵母菌的摇瓶发酵产率可达到 2 4 5 μg mL。抗菌特性研究表明 ,该表达产物具有广谱抗菌活性 ,对多数G- 菌及G+ 菌均有较好的抑菌活性 ,特别是对氨苄青霉素抗性菌和卡那霉素抗性菌抑杀效果更好 ;具有热稳定性和酸稳定性。这些特点使得重组抗菌肽CecA_mil在食品防腐、疾病防治和动物饲料添加剂等方面显露出很好的应用前景。

According to the partiality codon of Pichia pastoris, hybrid antimicrobial peptide CecA-mil gene was reconstructed, synthesized and cloned into pPICZα-A to construct the recombinant expression vector pPICZα-A-CM. The pPICZα-A-CM was transformed into yeast host strain X-33. Under the control of the promoter AOX1 (alcohol oxidase 1), a approximately 1.9 kD cecA-mil protein was expressed with the high level of 245μg/mL after optimized the requirements for the flask-shaking culture fermentation of the Pichia pastoris rX-33/pPICZα-A -CM. The hybrid antibacterial peptide had a broad spectrum antibacterial activity on both gram-positive and gram-negative bacteria, especially showed potent antibacterial activity against ampicillin-resistant and kanamycin- resistant bacteria, such as Staphylococcus aureus (cowan Ⅰ) and pathogenic E.coli (O1) from chicken. In addition, the hybrid antibacterial peptide showed an extreme heat-stable and acid-stable characteristic. Based on these characteristics, the recombinant antibacterial peptide CecA-mil display application foreground in the field of antisepsis of food, prevention of disease, additives of animal feedstuff and so on.