乙型肝炎表面抗原124aa分子在大肠杆菌中的高效表达

EXPRESSION OF THE HEPATITIS B SURFACE ANTIGEN FRAGMENT WITH 124 AMINO ACIDS IN E.coli

利用聚合酶链反应特异性扩增编码乙型肝炎表面抗原（ＨＢｓＡｇ）羧基末端１２４个氨基酸的基因片段，并将其在大肠杆菌中获得了高效表达。表达产物氨基末端有１个含６组氨酸肽段的２０氨基酸融合部分，分子量１６１７８Ｄａ，以包含体形式存在，约占细菌总蛋白的２２％。以ＨｉＴｒａｐ亲和层析纯化，纯度可达９５％以上。分别用抗ＨＢｓＡｇ多克隆抗体和抗ＨＢｓＡｇａ单克隆抗体进行ＥＬＩＳＡ检测表明，该蛋白具有ＨＢｓＡｇ反应原性。

The gene fragment coding the 124 amino acids of the carboxyl terminus of hepatitis B surface antigen(HBsAg)was amplified by polymerase chain reaction(PCR)and the shorted HBsAg was expressed in E.coli in a fusion protein fashion.The fusion protein was 16178Da in molecular weight and contained a 20 amino acid fusion portion at its amino terminus which contained a six histidine peptide segment.The expressed proteins aggregated into inclusion bodies weigh about 22% of the total bacteria proteins.It was easily purified with the HiTrap affinity matrix with a purity up to 95%.ELISA detection showed that the protein could be recognized by polyclonal antibodies against HBsAg and monoclonal antibody against HBsAg a determinant.