Influenza hemagglutinin: Difference between revisions

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Eric Martz, Savannah Anderson, Eran Hodis, Tim Herman, David Canner, Michal Harel

Revision as of 23:40, 15 July 2009 view source Savannah Anderson (talk \| contribs) 115 edits No edit summary ← Older edit		Revision as of 23:53, 15 July 2009 view source Savannah Anderson (talk \| contribs) 115 edits No edit summary Newer edit →
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	After the virus has bound to the cell membrane, the cell engulfs the viral capsule through the process of endocytosis. Included on the lining of the endosome are ion pumps, were originally used to pump ions out of the cell and maintain a proper pH level. As a part of the endosomal lining, the pumps continue to pump ions, but now into the endsome. This causes the pH surrounding the viral capsule to become acidic.		After the virus has bound to the cell membrane, the cell engulfs the viral capsule through the process of endocytosis. Included on the lining of the endosome are ion pumps, were originally used to pump ions out of the cell and maintain a proper pH level. As a part of the endosomal lining, the pumps continue to pump ions, but now into the endsome. This causes the pH surrounding the viral capsule to become acidic.

	When the pH level reaches 5.5, the HA1 protien shifts its position, rearranging to allow the HA2 protein to access the endosomal membrane. The HA2 chain begins to rearrange, and the loop shown in blue refolds into a helix at pH5.		When the pH level reaches 5.5, the HA1 protien shifts its position, rearranging to allow the HA2 protein to access the endosomal membrane. The HA2 chain begins to rearrange, and the loop shown in blue refolds into a helix at pH5. This causes the HA2 chain to reform into the longest known alpha helix in nature. This allows the fusion peptide to become embedded in the endosomal membrane. The C-terminus of the HA2 also rearranges, positioning the viral membrane in close proximity to the endosomal membrane and allowing membrane fusion to occur. This allows the viral RNA to be released from the capsule and into the host cell cytoplasm.