乙肝表面抗原结合蛋白SBP在毕赤酵母中的表达纯化及功能鉴定

Expression, purification and characterization of HbsAg binding protein in Pichia pastoris

摘要:

乙肝表面抗原结合蛋白(HBsAg binding protein, SBP)是本实验室发现的一种人源蛋白, 该蛋白与人乙型肝炎病毒HBV表面抗原HBsAg存在特异性的结合能力。此前的研究证实SBP具有增强乙肝疫苗免疫效果的作用。为进一步研究该蛋白的生理功能和作用机制, 利用毕赤酵母表达系统进行了SBP的表达菌株构建, 筛选得到了SBP的高效表达菌株。发酵产物经过分离纯化, 最终得到了大量高纯度的真核来源的目的蛋白。通过SDS-PAGE、高效液相色谱、Western blotting和质谱鉴定, 证实所得到的蛋白具有较高的纯度和完整性。通过ELISA方法初步证实了其与乙肝表面抗原具有较好的结合能力。该研究为进一步进行SBP的体内外功能研究及免疫增效研究打下了基础。

Abstract:

Human hepatitis B virus surface antigen (HBsAg) binding protein(SBP) shows a specific binding ability to HBV surface antigen HBsAg. Previous work proved an ability of SBP to enhance the immune response of HBsAg vaccine. To investigate the function and mechanism of this protein, we constructed SBP-expression strains with Pichia pastoris expression system. We screened these strains and have got an expression strain with high protein expression quantity. Fermentation product was collected and purified to gain a large amount of purified protein. Identification of purified SBP with SDS-PAGE, High performance liquid chromatography, Western blotting and mass spectrometry suggested that the protein was highly purified and with a good integrity. ELISA test of purified SBP showed a significant binding ability to HBsAg, suggesting a good protein activity. This work offers a solid foundation to the research of SBP function and mechanism of immune enhancement.