1918 Influenza Hemagglutinin
PDB ID: 1RUZ
Hemagglutinin, a trimeric transmembrane protein found on viral membranes, helps viruses enter and release their viral RNA into cells. The outer portion of the protein targets sialic acid chains (present on glycoproteins) on cell membranes to “dock” the virus on the cell surface. Once the virus is internalized via endocytosis, the cell releases acids to digest the endosomal contents. However, the lower pH induces a conformational change in the protein, allowing the internal portions (initially folded and hidden under the outer parts) to attach to the endosomal membrane. The protein then pulls the viral and endosomal membranes together, allowing them to fuse together and to release viral RNA into the cell. I chose to model Hemagglutinin using tissues (folded into carnations) since this particular Hemagglutinin model was from the 1918 influenza virus. The tissue flowers were colored by spraying food coloring onto them; the alpha helices on the inside were represented by curled pipecleaners; and the part of the protein that attaches to the endosomal membrane was represented by paperclips.