H5N2亚型禽流感病毒血凝素裂解位点碱性氨基酸对应mRNA核苷酸的二级结构分析

以H5N2亚型禽流感病毒毒株血凝素蛋白裂解位点碱性氨基酸为研究对象，对其密码子偏好性和对应mRNA序列的折叠二级结构特点进行研究和分析。旨在探讨裂解位点氨基酸对应mRNA核苷酸片段的二级结构与病毒致病力的关系，希望能对禽流感病毒的研究提供一些基础性信息。将mRNA样本按照序列等步长递增的方法，用RNAstructure 4．1程序预测这些样本的动态延伸折叠二级结构。序列和结构的分析结果：裂解位点的碱性氨基酸对富含腺嘌呤的密码子有强烈偏好；与碱性氨基酸对应的mRNA片段上的核苷酸主要位于折叠二级结构的单链环区，少数位于配对螺旋区。结果表明：裂解位点氨基酸对应的mRNA核苷酸形成发夹端环的大小与其碱性氨基酸的多少具有正相关性。

Secondary structural analysis of the mRNA regions encoding the hemagglutinin cleavage site basic amino acids of the avian influenza virus H5N2 subtype samples

Here we report the codon bias and the mRNA secondary structural features of the hemagglutinin （HA） cleavage site basic amino acid regions of avian influenza virus H5N2 subtypes. After studying the relation between the secondary structure characteristics of the mRNA nucleotide segments and their pathogenicity, we hope this work can provide basic messages for the research of the avian influenza virus. We have developed a dynamic extended folding strategy to predict RNA secondary structure with RNAstmcture4.1 program in an iterative extension process. Statistical analysis of the sequences showed that the HA cleavage site basic amino acids favor the adenine - rich codons, and the corresponding mRNA fragments are mainly in the folding states of single - stranded loops. The result also showed that there is a relation between the size of the mR.NA hairpin loops and the number of the basic amino acids at the HA cleavage site.