摘要
目的:构建人血清白蛋白(HSA)-胸腺五肽(TP5)融合蛋白表达载体,并在毕赤酵母中表达,阐明其生物学活性。方法:利用基因重组技术构建HSA-TP5融合基因,并转染至毕赤酵母中从而构建其真核表达体系,通过琼脂糖凝胶电泳分离及试剂盒纯化获得PPICZαC-HSA-TP5真核重组表达质粒;采用两步发酵法对HSA-TP5基因工程菌进行高密度发酵,对发酵液上清蛋白沉淀浓缩,通过SDS-聚丙烯酰胺凝胶电泳法、阳离子交换层析及疏水层析等方法分离纯化蛋白;采用MTT法检测该融合蛋白促淋巴细胞增殖活性。结果:PCR法获得HSA目的基因片段长度为1 845bp。酶切鉴定融合质粒HSA-TP5-pPICZαC得到片段长度为707bp。测序分析,目的基因HSA和TP5序列与GenBank公布的基因序列完全一致,并正向连接融合。PCR法鉴定PPICZαC-HSA-TP5真核重组质粒与酵母基因组DNA整合,与对照组比较,转化组出现基因片段长度为1 860bp。SDS-PAGE分析,在甲醇诱导后72h内,随着诱导时间延长,HSA-TP5融合蛋白表达量逐步升高。利用阳离子交换层析及AKTA多功能蛋白纯化系统纯化得到HSA-TP5融合蛋白。MTT法检测,HSA-TP5融合蛋白与TP5蛋白具有一致的促淋巴细胞增殖活性。结论:通过构建HSA-TP5毕赤酵母真核表达体系可获得HSA-TP5融合蛋白并具有生物学活性。
Objective：To construct the expression vector of the fusion protein of human serum albumin（HSA）and thymopentin（TP5）and to express it in Pichia pastoris,and to elucidate the biological activity of fusion protein.Methods：The HSA-TP5 fusion gene was constructed by gene recombination and transfected into Pichia pastoris to construct the eukaryotic expression system of HSA-TP5.The recombinant eukaryotic expression plasmid of PPICZα-HSA-TP5 was obtained by agarose gel electrophoresis and purification reagent.The two step fermentation method was used to ferment gene engineering bacteria of HSA-TP5 in high density,and the fermentation supernatant protein was precipitated and concentrated;the purified fusion protein was obtained by cation exchange chromatography and hydrophobic chromatography and analyzed by SDS-polyacrylamide gel electrophoresis.The effect of the fusion protein on the proliferation of lymphocytes was detected by MTT assay.Results：The HSA target gene fragment with length of 1 845 bp was achieved by PCR method.The HSA-TP5-pPICZαC fusion plasmid was identified by restriction endonuclease digestion,and the fragment length was 707 bp.The sequence analysis showed that the HSA and TP5 sequences of the target genes were identical with the gene sequences reported in GenBank and were fused by forward fusion.PCR method confirmed that the eukaryotic recombinant plasmid PPICZαC-HSA-TP5 was integrated into the yeast genome,and compared with control group,the target gene PCR product length was found to be 1 860 bp.SDS-PAGE analysis showed that the expression level of HSA-TP5 fusion protein was gradually increased with the induction time within 72 h.HSA-TP5 fusion protein was purified by cation exchange chromatography and AKTA multifunctional protein purification system.The MTT assay results showed that HSA-TP5 fusion protein was consistent with TP5 protein in promoting lymphocyte proliferation activity.Conclusion： HSA-TP5 fusion protein can be obtained by constructing the eukaryotic expression system of Pichia pastoris and owns the biological activity.
出处
《吉林大学学报（医学版）》
CAS
CSCD
北大核心
2017年第5期948-952,I0005,共6页
Journal of Jilin University：Medicine Edition
基金
吉林省教育厅"十二五"科学技术研究项目资助课题(吉教科合字[2014]第173号)
吉林省科技厅分子老年医学重点实验室项目资助课题(20130624003JC)
吉林省吉林市科技计划项目资助课题(201437024
2015233007)
