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Hemagglutinin ThePROTEIN

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					Hemagglutinin:   The PROTEIN
          Jason Zhang
    COSMOS            Cluster 8
            8/2/2007
                       Outline

•   Background
•   Structure
•   Function
•   Current Research and Importance
•   Conclusion
                    Background Info
• Virus structure and membrane glycoproteins1




                                                http://www.scientificpsychic.c
                                                om/health/virus.html
• Hemagglutinin: an antigen




                                            http://cache.eb.com/eb/image?id
                                            =20896&rendTypeId=4



• Hema - blood, glutinin – agglutination2
                More Background Info
• 16 different subtypes

• Subtypes H1, H2, and H3 attack humans2

• Subtype H1 and the 1918 Spanish influenza3
            Structure of Hemagglutinin5
• Cylindrical, about 135 Angstroms long




• Composed of three monomers, each with 3 binding “heads”
  The Hemagglutinin Monomer Subdomains6
• The receptor binding

• The vestigial esterase

• The fusion helix


                                   Rasmol
                          Function
• Two basic functions:

   – Recognition and binding

   – Membrane fusion
               Recognition and Binding
• Proteins bind to cell receptors(currently still unknown)



• Sialic acid binding sites




                     http://publications.nig
                     ms.nih.gov/findings/m
                     ar06/agbandje-
                     mckenna_files/textmos
                     tly/slide4.html
            Protein-Receptor Complex
• The 130-loop,
the 220-loop,
and the 190–helix

• Hydrogen bonding
between carbonyl
or nitrogen6


                                       http://www.sciencemag.o
                                       rg/cgi/reprint/sci;303/566
                                       5/1838.pdf
                  Membrane Fusion
• Endocytosis and formation of the endosome

• Digestion lowers pH, hemagglutinin changes conformation2

• “Grappling Hook” Model6




                                                     http://faculty.virginia.edu/tamm/i
                                                     mages/fusion_sequence.jpg
                  Hemagglutinin Today
• There is still no cure for the flu

• Birds, pigs, and humans – subtype H5N11




                                            http://www.fontcraft.
                                            com/BirdFlu.jpg
                     Key Questions
• What cell receptor does hemagglutinin bind to?

• What are the intermolecular interactions between the
  receptor binding domain and the cell receptor?
                 Conclusion/Summary
• Hemagglutinin is found on the influenza virus, with 16
  different subtypes
• Consists of 3 monomers each with receptor binding, vestigial
  esterase, and fusion subdomains
• The threat of a hemagglutinin mutation
                                                      Works Cited

1.   "CDC - Influenza (Flu) | The Influenza (Flu) Viruses." Centers for Disease Control and Prevention. 23 Oct 2006. 2 Aug 2007
     <http://www.cdc.gov/flu/about/fluviruses.htm>.
2.   "Hemagglutinin - Wikipedia, the free encyclopedia." Main Page - Wikipedia, the free encyclopedia. 3 Mar 2004. 2 Aug 2007
     <http://en.wikipedia.org/wiki/Hemagglutinin>.
3.   "Influenza." Main Page - Wikipedia, the free encyclopedia. 9 Apr 2002. 2 Aug 2007 <http://en.wikipedia.org/wiki/Influenza>.
4.   Marcey, David, and Eric Mazur. "Influenza Hamagglutinin." California Lutheran University - Welcome. 22 Jan 2005. 2 Aug 2007
     <http://www.callutheran.edu/BioDev/omm/jmol/flu_div/start.html#intro>.
5.   Woods, Heather. "Structural Analysis of Hemagglutinin from the 1918 Influenza Pandemic." SSRL- Stanford Synchrotron Radiation
     Laboratory. 30 Aug 2004. 2 Aug 2007 <http://www-ssrl.slac.stanford.edu/research/1918flu_summary.html>.
6.   The Structure and Receptor Binding Properties of the 1918 Influenza Hemagglutinin
     Science 303, 1838 (2004);
     DOI: 10.1126/science.1093155
                   Special Thanks
• Professor Toby Allen
• Mr. Wayne Raymond
Thank You, Thank You.

				
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