新疆家蚕抗菌肽基因突变及其抗菌活性的研究  

Study on the Gene Modification and Antimicrobial Activity of Cecropin-XJ

作　　者：刘忠渊[1] 毛新芳[1] 张兰廷[1] 张富春[1] 

机构地区：[1]新疆大学生命科学与技术学院新疆生物资源基因工程重点实验室,乌鲁木齐830046

出　　处：《生物技术通报》2011年第9期147-156,共10页Biotechnology Bulletin

基　　金：新疆维吾尔自治区自然科学基金项目(200821120);科技支疆项目(200991130);博士启动基金项目(BS090126)

摘　　要：为了改变抗菌肽的结构参数,探讨其结构与活性的关系,采用PCR扩增和人工合成基因的方法,对新疆家蚕抗菌肽基因进行改造及原核表达蛋白的抑菌活性研究。结果表明,α-螺旋、两亲性、疏水性、净正电荷数和关键氨基酸的替换等参数是相互依赖、相互影响,协同发挥作用,任何一个参数的改变都会影响抗菌肽整体的活性。α-螺旋是抗菌肽功能有效性的结构基础,但其所处的位置可能并不影响抗菌活性;两亲性结构是抗菌肽与生物膜相互作用的重要结构;疏水性程度必须保持在一定的范围内;在一定范围内增加多肽的阳离子能够增加抗菌活性,但正电荷数和抗菌活性之间无绝对正相关性;色氨酸的存在及抗菌肽的C-末端酰胺化能增强抗菌活性。The purpose of this study is to modify the structural parameters of cecropin-XJ from Xinjiang Silkworm,and to investigate the structure-activity relationship of antimicrobial peptides.In this study,three Cecropin-XJ genes were modified by PCR and three other new genes were synthesized.The antimicrobial activity of the purified fusion protein was analyzed by agarose diffusion assay and minimal inhibitory concentration（MIC）.It showed that structural parameters including α-helix,amphipathicity,hydrophobicity,net positive charge,crucial amino acid substitution are interdependent,therefore,modification of one parameter often leads to significant changes to one or more of the others.Alpha-helix plays an important role in the function of antimicrobial,the location of which was of no importance to cecropin-XJ.Amphipathicity may play a predominant role in regarding interaction with target membranes.Hydrophobicity is an essential feature for interactions between antimicrobial peptide and membrane,but its degree must be kept in a certain range.Within the certain range,increasing peptide cationicity is generally associated with increasing antimicrobial potency.However,there is a limit beyond which increasing positive charge no longer confers increased activity.Tryptophan and C-terminal acylation play a crucial role in killing bacteria for Cecropin-XJ.

关 键 词：新疆家蚕抗菌肽 结构参数 基因突变 结构与活性 

分 类 号：S881[农业科学—特种经济动物饲养]