摘要
目的:研究人ⅡA型磷脂酶A2(groupⅡA phospholipase A2,PLA2GⅡA)碳末端衍生多肽的分子结构与杀菌活性的关系。方法:以人PLA2GⅡA一级结构碳末端的26个氨基酸残基为模板,分别合成3条多肽如下:①直链肽P1-26;②将其中一半的碱性氨基酸替换成中性氨基酸的P2-26;③碱性氨基酸(组氨酸和赖氨酸)全被替换成精氨酸的P3-26。采用琼脂铺板计数法测定多肽的杀菌活性。将不同浓度的3种多肽分别与G+菌(枯草杆菌)和G-菌(大肠杆菌)在37℃孵育2h,然后铺板并置于37℃恒温箱培养18～24h,记录每一琼脂板上的菌落数(CFU),并计算多肽作用后的杀菌率。结果:①碱性氨基酸减少的P2-26杀G+菌活性降低,仅为P1-26的1/4,但对G-菌杀菌效应稍增高;②碱性氨基酸全为精氨酸的P3-26杀G+菌和G-菌的活性与P1-26相比均明显降低。结论:人PLA2GⅡA衍生杀菌多肽P1-26的杀菌作用与其所含有的碱性氨基酸密切相关,减少碱性氨基酸的量可以减低它杀G+菌的活性,改变碱性氨基酸的类型也可以影响它的杀菌活性。
Objective：To study the relationship between bactericidal activity and molecular structure of the polypeptides derived from the C-terminal of human group ⅡA phospholipase A2（PLA2GⅡA）.Methods： According to the C-terminal 26 amino acid residues sequence of Human PLA2GⅡA,three polypeptides were synthesized respectively as follow： ①P1-26（pep10101321）： natural straight chain polypeptide;②P2-26（pep10101322）： half of the basic amino acids（3Lysine/1Argine） were substituted by neutral amino acids（3Leucine/1Serine）;and ③ P3-26（pep10101324）： basic amino acids（Histidine and Lysine） were all substituted by argine.The bactericidal activity was determined by agar plating-method.Three polypeptides in different concentration were incubated with Gram positive bacteria（Bacillus subtilis） and Gram negative bacteria（Escherichia coli） at 37℃ for 2 hours in a water bath respectively.Then diluted the reaction solution and poured agar plates.After incubation for 18-24 hours in the thermostated container at 37℃,counted the colony formed unit and calculated the bactericidal rates.Results： ① the bactericidal activity on Gram positive bacteria of P2-26 decreased about 4 times compared to P1-26,but the bactericidal activity on Gram negative bacteria of P2-26 increased slightly;② the bactericidal activity both on Gram positive bacteria and Gram negative bacteria of P3-26 decreased dramatically,compared to P1-26.Conclusion： The bactericidal activity of the polypeptide P1-26 which derived from the C-terminal of PLA2GⅡA is closely related to the basic amino acids in the peptide molecule.The bactericidal activity on Gram positive bacteria is decreased as basic amino acid residues are reduced,the type of basic amino acid can also impact its bactericidal activity.
出处
《广西医科大学学报》
CAS
2012年第2期172-175,共4页
Journal of Guangxi Medical University
基金
广西自然科学基金资助项目(No.2010GXNSFA013246)
广西医疗卫生重点科研课题(No.重2011075)
关键词
ⅡA型磷脂酶A2
衍生肽
杀菌活性
分子结构
构效关系
group ⅡA phospholipase A2； derived peptides； bactericidal activity； molecular structure； structure-activity relationship
