A Recommended Numbering Scheme for Influenza A HA Subtypes

Comparisons of residues between sub-types of influenza virus is increasingly used to assess the zoonotic potential of a circulating strain and for comparative studies across subtypes. An analysis of N-terminal cleavage sites for thirteen subtypes of influenza A hemagglutinin (HA) sequences, has previously been described by Nobusawa and colleagues. We have expanded this analysis for the eighteen known subtypes of influenza. Due to differences in the length of HA, we have included strains from multiple clades of H1 and H5, as well as strains of H5 and H7 subtypes with both high and low pathogenicity. Analysis of known structures of influenza A HA enables us to define amino acids which are structurally and functionally equivalent across all HA subtypes using a numbering system based on the mature HA sequence. We provide a list of equivalences for amino acids which are known to affect the phenotype of the virus.流感病毒亚型间的残基比较，正日益被用于评估流行毒株的人畜共患潜力，以及开展跨亚型的比较研究。此前，野泽（Nobusawa）及其同事曾针对13种甲型流感血凝素（hemagglutinin，HA）序列的N端切割位点展开分析并报道相关成果。本研究将该分析拓展至目前已知的全部18种流感病毒亚型。鉴于HA蛋白长度存在差异，本研究纳入了H1和H5亚型的多个进化枝（clade）毒株，同时纳入了兼具高致病性与低致病性的H5及H7亚型毒株。通过对已知甲型流感HA蛋白结构的分析，我们可基于成熟HA序列的编号体系，确定所有HA亚型间结构与功能均等价的氨基酸残基。我们整理了一批经证实可影响病毒表型的等价氨基酸残基列表。