Structural comparison among the 2013-2017 avian influenza A H5N6 hemagglutinin proteins: A computational study with epidemiological implications.

Avian influenza viruses easily spread allowing viral re-assortment to simply occur which in-turn increases the potential for a pandemic. A novel 2013 H5N6 influenza strain was detected among the avian population and was reported to continuously evolve, however, this was never structurally demonstrated. Here, we elucidated the putative structural evolution of the novel H5N6 influenza strain. Throughout this study, we analyzed 2013-2017 H5N6 HA protein models. Model quality was first verified before further analyses and structural comparison was made using superimposition. We found that Leu was inserted at position 1291 among the 2013-2015 models while Leu was not inserted among the 2016-2017 models. Moreover, presence of Leu at position 1291 shifts residue E1261 by 159.6° affecting nearby residues which may explain the difference between the 2013-2015 and 2016-2017 HA structural groups. Similarly, we believe that our results would support the hypothesis that the current H5N6 strain is still continuously evolving.