Final Project: Hemagglutinin
Abstract
Hemagglutinin is membrane protein found on the influenza virus. This project focuses on hemagglutinin subtype H1, the one involved in the 1918 Spanish influenza. The project concentrates on explaining the structure and function of the protein, while trying to give an accurate account of the molecular interactions between the protein and the host cell membrane. Specifically, hemagglutinin is a protein composed of three monomer protein strands. Each monomer consists of three important subdomains called the fusion subdomain, the receptor binding subdomain, and the vestigial esterase subdomain. Each has an important function in a virus infection. This project hopes to provide info for future research into preventing and perhaps curing influenza.
Background
Viruses use simple mechanisms to attack and infect their hosts. One step in a virus attack is the binding of the virus to the host cell. The virus does this by using surface proteins that can recognize and attach to receptors on the cell membrane and somehow injects its genetic material into the host cell.3 Hemagglutinin is a kind of surface protein found on the lipid envelopes of the influenza virus.
Hemagglutinin gets its name from its effect on making red blood cells clump together and agglutinate. The influenza virus has many hemagglutinin proteins, and each can attach to a red blood cell, causing the red blood cells to come together around the virus. This causes thickening of the blood and affects the clotting ability of blood.2 There are 16 different subtypes of the protein, ranging from H1 to H16. The more important ones are H1, H2, and H3, the subtypes found on the human influenza virus.2 This proj...
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... - Wikipedia, the free encyclopedia. 3 Mar 2004. 2 Aug 2007 .
3. "Influenza." Main Page - Wikipedia, the free encyclopedia. 9 Apr 2002. 2 Aug 2007 .
4. Marcey, David, and Eric Mazur. "Influenza Hamagglutinin." California Lutheran University - Welcome. 22 Jan 2005. 2 Aug 2007 .
5. Woods, Heather. "Structural Analysis of Hemagglutinin from the 1918 Influenza Pandemic." SSRL- Stanford Synchrotron Radiation Laboratory. 30 Aug 2004. 2 Aug 2007 .
6. The Structure and Receptor Binding Properties of the 1918 Influenza Hemagglutinin
Science 303, 1838 (2004);
DOI: 10.1126/science.1093155
A brief review of the historical year of 1918 when people were informed to take precaution against influenza, while their children came up with a catchy tune for the "worst epidemic the United States has ever known"1 and comparing it with the influenza of today.
Bloodborne pathogens are viruses that deteriorate cells within the body. A virus is a submicroscopic parasitic organism that feeds on cells. Viruses are dependent on cells for their nutrients so the virus survive and reproduce. Every virus consists of either deoxyribonucleic acid (DNA) or ribonucleic acid (RNA). A virus can contain a strand of one or the other, but not both. This RNA or DNA is contained within a protein shell for protection. A virus is a parasite that is dependent upon cells for metabolic and reproductive requirements. By using the cell the virus makes the host very ill by redirecting cellular activity to make more viruses.
Nancy K. Bristow, American Pandemic, The Lost Worlds of the 1918 Influenza Epidemic (New York: Oxford University Press, 2012), 193
However due to globalization, import and export viruses is more easily transmitted. Over the past century the global community especially Asian has been affected with new strains of the influenza virus. The changes in the virus can occur in two ways “antigenic drift” which are gradual changes in the virus over time. This change produces new strains that the antibody may not recognize. “Antigenic shift” On the other is a sudden change in the influenza virus which ‘’ results in a new influenza A subtype or a virus with a hemagglutinin or a hemagglutinin and neuraminidase combination that has emerged from an animal population,” as seen with H5N1 virus. This change leaves people defenseless against this new virus. (CDC, 2013) Currently there is no vaccine to combat all strains therefore “Planning and preparedness for implementing mitigation strategies during a pandemic requires participation by all levels o...
--------------------------------------------------------------------- [1] Essen, G. A., "The Socio-Economic Impact of Influenza". http://www.eswi.org/Bulletin_October_1997.cfm [2] Frayha, Husn. " Influenza Vaccination: A Call for Action" http://www.kfshrc.edu.sa/annals/176/97-248R.html [3] "Influenza". http://www.caw.ca/whatwedo/health&safety/factsheet/hsfssubstanceno37.asp
"Pandemic Flu History." Home. U.S. Department of Health & Human Services, n.d. Web. 23 Mar.
The virus is primarily spherical shaped and roughly 200nm in size, surrounded by a host-cell derived membrane. Its genome is minus-sense single-stranded RNA 16-18 kb in length. It contains matrix protein inside the envelope, hemagglutinin and neuraminidase, fusion protein, nucleocapsid protein, and L and P proteins to form the RNA polymerase. The host-cell receptors on the outside are hemagglutinin and neuraminidase. The virus is allowed to enter the cell when the hemagglutinin/ neuraminidase glycoproteins fuse with the sialic acid on the surface of the host cell, and the capsid enters the cytoplasm. The infected cells express the fusion protein from the virus, and this links the host cells together to create syncitia.
For long before the 1918 pandemic, doctors had been trying to isolate the microorganism that causes influenza. In 1892, one man, Dr. Friedrich Johann Pfeiffer, believed he had the answer. His discovery, Pfeiffer’s bacillus or Hemophilus influenzae, was widely known as the culprit. However, during the first wave of the 1918 pandemic, doctors lost faith in Pfeiffer’s bacillus. They searched for it in patients, but rarely found it. In the second wave, the bacterium was present in many, but by no means all, cases of Spanish flu. If it was the cause of influenza, it should have been present in all cases (Kolata, Flu 64-65).
Kent, Susan Kingsley. The Influenza Pandemic of 1918-1919: A Brief History with Documents. Boston: Bedford/St. Martin's, 2013. Print.
Influenza is a major public health problem which has outbreaks all over the world. Resulting in considerable sickness and death rates. Furthermore, it is a highly infectious airborne disease and is caused by the influenza virus. Influenza is transmitted easily from one person to another person, which has a great impact on society. When a member of society becomes sick, it is more prone to spread to other people.
Billings, Molly. “The Influenza Pandemic of 1918.” virus.stanford.edu. Modified RDS, 2005. Web. 12 Nov. 2013.
At no time was a search for the cure for influenza more frantic than after the devastating effects of the pandemic of 1918. The pandemic killed somewhere between twenty and a hundred million people, making it twenty five times more deadly than the ordinary cough and sneeze flu. The symptoms of this flu were like something straight out of a horror movie: the victim’s facial complexion changed to a dark, brownish purple, the feet turned black, and they began to cough up blood. Eventually, death was caused, literally by drowning, when the victim’s lungs filled with their own blood. The first scientist to claim to solve the enigma of influenza was Dr. Friedrich Johann Pfeiffer. He isolated a bacterium he named Hemophilus influenzae from the respiratory tract of those who had the flu in the pandemic of 1890. He was believed to be correct in his discovery until the pandemic of 1918, when scientists searched the respiratory tracts of influenza victims and only sometimes found his bacterium. Robert E. Shope and his mentor Paul Lewis were the next to attempt to crack the code of influenza. They chose to study the disease in pigs, a controversial choice because many people believed that the swine influenza pigs were contracting was not the same as the human flu. The first experiment they ran was ba...
“The Influenza Pandemic of 1918.” Billings, Molly. Stanford University Virology. June 1, 1997. retrieved from http://virus.stanford.edu/uda/
The swine influenza or swine flu is a respiratory disease in pigs that is caused by the type A influenza viruses. These viruses are referred to as swine flu viruses but scientifically the main virus is called the swine triple reassortant (tr) H1N1 influenza virus. When the viruses infect humans they are called variant viruses. This infection has been caused in humans mainly by the H1N1v virus in the United States. The H1N1 virus originates in animals due to improper conditions and the food they ingest. The virus stays in latency form, thus harmless to the respective animal. The longer the animals survive the more likely the virus is to develop and strengthen making it immune to vaccines. The virus reproduced through the lytic cycle. The virus injects its own nucleic acids into a host cell and then they form a circle in the center of the cell. Rather than copying its own nucleic acids, the cell will copy the viral acids. The copies of viral acids then organize themselves as viruses inside of the cell. The membrane will eventually split leaving the viruses free to infect other cells.
Virus- An infectious agent found in virtually all life forms, including humans, animals, plants, fungi, and bacteria. Viruses touch us every day through water, food, physical contact, blood, animals, or even, the air you breathe. Although most are harmless, there are some that are not.... ...