Hemagglutinin (HA) protein plays an important role in binding the influenza virus to infected cells and therefore mediates infection. Deposited HA sequences of 86 Asian strains of influenza A (H1N1) viruses during the first outbreak were obtained from the NCBI database and compared. Interaction of the HA protein of influenza A (H1N1) virus with the human sialic acid receptor was also studied using bioinformatics.
The surface of the dengue virus is composed of 180 copies of a multifunctional envelope glycoprotein that acts at several stages of viral infection. When the virus is in the endosome, these glycoproteins undergo major conformational rearrangements owing to the protonation of histidine side chains. This protonation allows for the formation of trimers, thereby triggering fusion between the viral and the host membranes.