抗菌肽Protegrin基因的定点诱变改良研究

Study on Improvement and Site-directed Mutagenesis of Antibacterial Peptide Protegrin

通过对抗菌肽Protegrin成熟肽的氨基酸组成和作用机理分析,并根据已报道的Protegrin基因序列设计引物,PCR扩增获得定点诱变的突变体基因pg-g,其编码蛋白的末端相对于野生型增加1个非极性氨基酸Gly.利用表达载体pET-28a将突变体基因pg-g转化到大肠杆菌BL21(DE3),IPTG诱导表达后,经SDS-PAGE检测表明目的蛋白得到成功表达.通过对表达产物进行抑菌实验发现,定点突变基因pg-g表达产物对大肠杆菌的抑菌效果有明显提高.

According to the reported sequences of the mature peptide of protegrin and its gene,primers were designed to mutate its protein by adding a nonpolar amino acid （Gly） to its end. The mutant type protegrin gene pg-g was amplified by PCR. Then the pg-g gene was ligated with the expression vector pET-28a and transferred into the E. coli BL21 （DE3）. After inducing by IPTG and detecting by SDS-PAGE, the target protein was expressed successfully. Results of antibacterial experiment indicated that the expression product of pg-g gene exhibited a higher antibacterial activity on Escherichia coli than its wild type.