溶剂环境对乙肝表面抗原 (HBsAg) 结构的影响

Effects of solvent environment on the structure of hepatitis B surface antigen (HBsAg)

摘要:

HBsAg作为乙肝疫苗的主要成分，是一种病毒样颗粒，由蛋白质和脂类通过非共价键作用形成。HBsAg保持完整结构对其功能非常重要，而目前未见对其在溶液中结构变化的研究。考察了不同溶剂环境 (温度、pH值、离子类型和盐浓度) 对HBsAg结构的影响。实验发现，HBsAg在常温下比较稳定，但在温度超过60℃时稳定性明显下降；pH值小于4.0时引起不可逆聚集，但在pH 5.0时的聚集部分可逆；不同离子对HBsAg的影响基本符合Hofmeister序列，不同之处是SO42?比F?更易引起HBsAg颗粒的聚集，在所考察的盐中，(NH4)2SO4对HBsAg有着较大的影响，0.4 mol/L时就会引起HBsAg聚集，随着浓度增加，聚集现象更加严重，所以在HBsAg的疏水层析中要谨慎使用 (NH4)2SO4。

Abstract:

As a virus-like particle, hepatitis B surface antigen (HBsAg) was the primary component of hepatitis B vaccine. HBsAg was maintained by the non-covalent interaction of proteins and lipids. The intact structure of HBsAg particle was vital to its function. However, there was no report about the effects of solvent environment on HBsAg structure. In this paper, we studied the effects of temperature, pH, ionic type and salt concentration on HBsAg structure. The results showed that HBsAg was stable at normal temperature, but began to denature above 60oC. The aggregation of HBsAg at pH 3.0 and 4.0 was nearly irreversible, but partly reversible at pH 5.0. The influence of ionic type on HBsAg was generally in accordance with Hofmeister sequence, except that SO42? caused more aggregation than F?. HBsAg aggregates started to be visible in 0.4 mol/L (NH4)2SO4, and the extent of aggregation increased with the salt concentration. Therefore, caution must be taken when using (NH4)2SO4 in the hydrophobic chromatography purification of HBsAg.