title: [Studies on the basis of molecular biology of the phase change of influenza A(H3N2) viruses].
abstract: The analysis of nucleotide sequences on HA1 domain of 35 strains of influenza A(H3N2) virus showed that their HA1 genes all were 984 nucleotides in length coding for a HA1 protein with 328 amino acids and there was not any occurrence of insertion or deletion of nucleotides on HA1 genes among them. The appearance of "O" phase strain of influenza A (H3N2) virus was closely related with substitution at 226 position of amino acid on HA1 protein molecule and the three-dimensional structural change of HA protein. The results in this paper indicated that the positions with multiple changes on HA1 protein molecule located at the top of HA protein, especially at antigenic determinant B site or receptor binding site. These further demonstrated that the substitution of amino acid on HA1 protein molecule was caused mainly by suppress of herd immunity. This study also showed that the position of the cysteine and proline residues on the HA1 protein molecule were conservative and that the glycosylation sites located at N and C terminals, especially at N terminal of the HA1 protein The significance of such a distribute delta of glycosylation sites in the evolution of viral genes and epidemiology still remain unknown.
authors.affiliation: Institute of Virology, Chinese Academy of Preventive Medicine, Beijing 100052.
authors.forename: Y
authors.initials: Y
authors.lastname: Guo
authors.forename: J
authors.initials: J
authors.lastname: Dong
authors.forename: M
authors.initials: M
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D053122:Influenza A Virus, H3N2 Subtype; D009980:Influenza A virus / Q000145:classification / Q000235:genetics*; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA