具强杀菌活性的兔Ⅱ型磷脂酶A2互补DNA克隆及其顺序确定的研究

目的:确定具强杀菌活性的兔Ⅱ型磷脂酶A2(PLA2)cDNA和蛋白质的一级结构,了解其杀菌功能与蛋白质一级结构的关系.方法:用PCR方法从兔骨髓cDNA库中克隆出Ⅱ型磷脂酶A2 cDNA并确定DNA顺序,推断出它的蛋白质一级结构;并与其它一些动物PLA2的结构进行比较.结果:成功获得了该磷脂酶A2的cDNA和蛋白质一级结构.它是目前上百种已知蛋白质一级结构的磷脂酶A2中碱性最强的蛋白,氨基酸组成中碱性氨基酸较丰富.其它具杀菌活性的哺乳动物Ⅱ型磷脂酶A2也都是碱性强的蛋白.结论:磷脂酶A2一级结构中富于碱性氨基酸是其具有杀菌功能的关键,而杀菌活性的强弱与其分子碱性强度呈正相关.

A STUDY OF COMPLEMENTARY DNA CLONING AND SEQUENCE DETERMINATION OF RABBIT TYPE PLA2 WITH POTENT BACTERICIDAL ACTIVITY

Objective: To determine cDNA and protein primary structure of rabbit type PLA2 with potent bactericidal activity,and to understand the relationship of bactericidal function and protein primary structure Methods: Cloning cDNA of rabbit type PLA2 from bone marrow cDNA library by PCR and determining DNA sequence;deducing protein primary sequence from cDNA sequence;comparing the primary structure with some others PLA2 structure Results: cDNA and protein primary structure of rabbit type PLA2 were obtained sucessfully;the PLA2 is the most basic protein among one hundred different PLA2s which protein primary structure were known;other PLA2s with bactericidal activity from mammal are very basic protein,too;amino acid compositions of the protein are rich in basic residues Conclusion: Amino acid compositions which are rich in basic residues are critically important for bactericidal activity and the potency of PLA2 bactericidal activity is positively correlating to basicity of the protein=