The Analysis of the Structure of Receptor Binding Site of Hemagglutin in Molecule of Influenza A Virus and of the Characteristics of Receptor.

我们用两种不同的方法研究了甲型流感病毒血凝素（HA）蛋白的受体结合结构：首先，我们合成了7种不同亚型的甲型流感病毒HA基因的cDNA，其核苷酸序列直到1989年才被报道。我们比较了13种血清型HA蛋白中与受体结合的氨基酸序列，并讨论了其受体结合位点的结构特征（参考文献10）。其次，我们利用定点突变技术构建了几种突变型HA cDNA，并在哺乳动物细胞中进行了表达。我们发现H1亚型HA蛋白上的氨基酸残基226对于受体结合是重要的我们还研究了H1和H3亚型人A型流感病毒HA蛋白在各亚型进化过程中的氨基酸变化，并讨论了这些氨基酸变化对受体结合位点的影响（参考文献2，4，9）。我们研究了13种不同亚型之间HA蛋白的受体特异性。我们发现除H3亚型外的所有HA蛋白在氨基酸残基226处具有维生素B1，但它们结合Neu 2 - 6 Gal或Neu 2 - 3Gal（参考文献10）。

We have studied the receptor binding structure on the hemagglutinin (HA) protein of the influenza A virus using two different methods.First, we synthesized cDNAs of the HA genes of influenza A virus which belong to seven different subtypes and whose nucleotide sequences were not reported until 1989. We compared the amino acid sequences which are composing the putative receptor binding structure among 13 serotype HA proteins and discussed the structural feature of the receptor binding site (ref 10).Secondly, we constructed several mutant HA cDNAs by site-directed mutagenesis and expressed them in mamalian cells. We found that the amino acid residue 226 on the HA protein of the H1 subtype was important for the receptor binding (ref 3, 10).We also investigated the amino acid changes on the HA proteins of the H1 and H3 subtypes of human influenza A virus during the evolution of each subtype and discussed the influence of these amino acid changes to the receptor binding site (ref 2, 4, 9).We have investigated the receptor specificity of HA proteins among 13 different subtypes. We found all HA proteins except H3 subtype have glutamin at the amino acid residue 226, but they bind to Neu2-6Gal or Neu2-3 Gal (ref. 10)