The Protein: Hemagglutinin (HA), a protein involved in the viral infection process. Specifically, HA helps cells internalize the virus and eventually the viral RNA.
Structure: Hemagglutinin is a trimeric transmembrane protein that extends from the surface of viruses. There are two types of chains in the enzyme, which we can call HA I and HA II. HA I (shown in blue) sits on the top of the protein while HA II (shown in yellow) is partially covered by HA I at first. There are also various carbohydrates on the Hemagglutinin surface. The viral strain (H1,H2, etc) can change if the location of the carbohydrate chains on the HA surface changes.
Hemagglutinin extending from virus surface
You can view the various hemagglutinin structures on PYMOL using the following PDB IDs:
- 1RD8 – uncleaved hemagglutinin from the 1918 influenza virus
- 1RUZ – the active form of hemagglutinin from the 1918 influenza virus
Mechanism of Action:
Video 1 shows the whole influenza virus infection process
Video 2 (skip to minute 4) shows the membrane fusion process
The blue portion of the protein targets sialic acids, which are part of some glycoproteins found on the cell membrane. Once the virus is docked on the cell membrane surface the cell internalizes the entire virus via endocytosis and begins releasing acids meant to digest the endosomal contents. However, the acids actually help activate conformational changes in Hemagglutinin, which allow the red portion of the protein to attach to the endosomal membrane. The yellow portion of the protein then moves up the the protein and brings the viral and endosomal membranes together. The viral RNA can enter the cell after the two membranes fuse together.
Hemagglutinin conformational changes
Modeling Ideas:
Some combination of these
1.Different colored flowers made of tissue to represent the different parts of the protein joined together by pipe cleaners or wire or something similar since the protein looks like a flower bouquet from certain angles. And tissues are the only cold/flu related material I can think of.
2. Tissue flowers for the HA I portion and then spiral bracelets to represent the alpha helices on the inside. Show conformational changes by moving the different pieces. Use a safety pin/bobby pin structure to pull two “membranes” (pieces of cloth?) together to represent the fusion of the viral and cell membranes.
3. Play-doh model of the three different stages?
Tissue carnations
Spiral bracelet
