rHBsAg 结合载脂蛋白 H 的机理研究

Study on the binding mechanism of rHBsAg with apo H

用酶免疫测定、配体印迹、酶水解、化学修饰等方法研究ｒＨＢｓＡｇ结合ａｐｏＨ的机理。实验结果表明，ｒＨＢｓＡｇ结合ａｐｏＨ是不依赖于Ｃａ＋＋、Ｍｇ＋＋等二价阳离子的，其最适ｐＨ在６．５～８．０。切除ａｐｏＨ上的神经氨酸和Ｎ－糖苷键，ａｐｏＨ结合力无变化，说明糖基不是ａｐｏＨ结合ｒＨＢｓＡｇ所必需的。化学修饰ａｐｏＨ的精氨酸残基对ａｐｏＨ的结合力无影响。然而，修饰其中几个赖氨酸残基即可减弱直至完全破坏ａｐｏＨ的结合力，说明赖氨酸残基与ａｐｏＨ结合ｒＨＢｓＡｇ有关。由于ａｐｏＨ与脂蛋白，特别是ＣＭ和ＨＤＬ结合，ＨＢＶ有可能通过ａｐｏＨ，结合ＣＭ、ＨＤＬ等，在脂蛋白代谢过程中进入肝细胞。

The enzyme immunoassay,ligand blotting,glycosidase digestion and chemical modification were used to study the binding mechanism of rHBsAg with apo H.Our results indicated that apo H binding with rHBsAg was not dependent on divalent cations and was optimal at pH 6 5￣8 0.Removal of sialic acid or complete removal of N linked carbohydrates from apo H did not change its ability to bind with rHBsAg,indicating that apo H carbohydrates were not involved in rHBsAg binding.Likewise,chemical modification of the arginine residues of apo H had no effect on binding.However,chemical modification of as few as three of the 29 lysine residues of apo H destroyed binding,indicating that one or a few lysines in apo H were involved in rHBsAg binding.Since apo H is associated with lipoproteins,particularly CM and HDL,it would be possible that HBV might bind to lipoproteins and be taken into hepatocytes.