Understanding the evolutionary relationship of hemagglutinin protein from influenza viruses using phylogenetic and molecular modeling studies.

The existing H1N1 (2009) swine flu is pandemic in nature and is responsible for global economic losses and fatalities. Among the eight gene segments of H1N1, hemagglutinin (HA) plays a major role in the attachment of the virus to the host cell surface and entry of viral RNA into the host cell leads to infection. In this study, sequence and phylogenetic analysis of the H1N1 (2009) HA, from Mexico City along with 1952 sequences, from different subtypes of pandemic influenza A virus were studied and results showed that the closest relationship of H1N1 (2009) Mexico strain was with the H1N1 (2007) Mallard Norway strain. Analysis of secondary structures predicted from the protein sequence revealed that diminishing of alpha helixes was observed in many areas of the sequences between the years 2005 to 2010. Conversely, analysis at the structural level is necessary to critically assess the functional significance. Structural level investigation was therefore done for the above said proteins by constructing the 3D...