ABSTRACT:Objective To perform a comparative bioinformatics analysis of H9 hemagglutinin of different strains of H9N2 avian influenza virus,and to find out the important bioinformatics data. Methods The amino acid and nucleotide sequences of H9 hemagglutinin of different strains of H9N2 avian influenza virus were retrieved from GeneBank.Clustal X and Bioedit softwares were used to align different amino acid and nucleotide sequences and to calculate the homologues. AntheProt5.0 software was used to predict the secondary structures.Results The length of open reading frame of H9 hemagglutinin was 1683 bp,which encoded a peptide consisting of 560 amino acids.The nucleotide and amino acid identities of H9 hemagglutinin of different strains of H9N2 avian influenza virus ranged from 90.6% to 99.8% and from 93.0% to 99.4%,respectively. There were 84 mutation sites(15.03%)in the sequence.The cleavage sites resulting in production of A1 and A2 subunits were located at aa333-aa341region of PSRSSR↓ GLF.The A334T and R335G mutations occurred in two of the 18 H9 hemagglutinin proteins,respectively.H9 hemagglutinin was rich in α-helices(25%-27%),β-pleated sheets(29%-32%),β-turn(25%-27%) and coil structures (17%-19%).The receptor binding domain was composed of R100,W161, T163,N191,198 (A/V/T),L202 and Y203.Conclusion The sequence and conformation of domain with important function in H9 hemagglutinin of different strains of H9N2 avian influenza virus are conservative and stable.%目的：对不同来源的 H9N2亚型禽流感病毒血凝素蛋白进行生物信息学比较分析，以找出重要的生物信息学数据。方法从 Genebank 的基因数据库中获取18株 H9N2亚型禽流感病毒 H9血凝素蛋白的核苷酸和氨基酸序列，运用 Clustal X，Bioedit 等国际通用软件进行氨基酸和核苷酸的序列比对，计算核苷酸及氨基酸的同源性。在线软件 Antheprot 分析二级结构。结果 H9型血凝素蛋白编码框架长约1683 bp，编码含560个氨基酸的多肽。18株 H9N2亚型禽流感病毒血凝素基因同源率为90．6％～99．8％，血凝素蛋白的氨基酸同源率为93．0％～99．4％，多肽序列中有84个变异位点，变异率为15．03％。血凝素蛋白 A1和 A2裂解序列为位于 aa333-aa341的PSRSSR↓GLF 序列；其中1株出现 A334T 变异，另一株则出现 R335G 变异。 H9血凝素蛋白富含潜在α螺旋（25％～27％），β折叠（29％～32％），β转角（25％～27％）及无规则卷曲（17％～19％）等结构；H9型血凝素蛋白受体结合位点是由 R100、W161、T163、N191、198（A／V／T）、L202、Y203位氨基酸残基折叠构成。结论 H9N2亚型禽流感病毒血凝素蛋白重要功能结构域的序列和空间结构相对保守稳定。
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