Protein Structure

Proteinaceous Infectious Particles, commonly known as Prions, are extremely rare misfolds of the protein PrPc, which cause fatally neurodegenerative diseases, and are theorized to be infectious only by the protein itself (U.S National Library of Medicine, 1998). This “protein-only theory” is still heavily debated today, as some scientists deny the theory, and there isn’t a significant amount of evidence on each side to qualify the theory or disprove it (Soto, C. 2011). The base “Prion” protein is encoded in the gene PRNP, while being non-infectious. Prions are most commonly found in human prion diseases, but they can also be in other animals in the form of Mad Cow Disease and Chronic Wasting Disease, classified as Bovine Spongiform Encephalopathies

Humans have to deal with many different diseases and the ones most disliked are the ones with no cures. Like cancer, transmissible spongiform encephalopathies have no cure, but they are more rare. These diseases are prion diseases which cause the brain to deteriorate. Prions are proteins that sometimes behave like viruses, which mean that they should have some form of nucleic acid, but since they don’t, they cause abnormalities. The nervous system contains many normal prions, but when an abnormal prion comes along, it transforms all the normal prions into abnormal ones. Bovine spongiform encephalopathy is found in cattle, but it can be transmitted to humans.

In bovine spongiform encephalopathy (BSE), the disease is caused by the misfolding of proteins that cause proteins and peptides to develop a fibrillary structure. The PrPc is a correctly folded prion and the misfolded form is called PrPSc. BSE occurs when the normal PrPc come into contact with the toxic PrPSc and the normal prion takes on the shape of the PrPSc. The normal chaperones are unable to convert the PrPSc back to the normal form. The PrPSc now takes on the role of chaperone and the conversion of PrPc prions continue over and over. PrPSc, now being hydrophobic avoids the water of the inner cell and begin to accumulate and form plaques along the neuronal cell membranes. The aggregation of the prions on the cell membrane eventually lead to cell death which produces the sponge-like appearance in the brain of cattle infected with BSE (Thompson, 2014).

their normal shape to an abnormal shape, however, the chemical composition of the protein remains

One wrong amino acid can change the shape of the protein and lead to a malfunctioning protein.

The U.S. Department of Agriculture (USDA) has tested hundreds of thousands of cattle for BSE. Researchers believe that the infectious agent that causes mad cow disease is an abnormal version of a protein normally found on cell surfaces, called a prion. For reasons still unknown, this protein becomes altered and destroys nervous system tissue (brain and spinal cord). There exists strong epidemiologic and laboratory evidence for a causal association between a new human prion disease called variant Creutzfeldt-Jakob disease (vCJD) that was first reported from the United Kingdom in 1996 and the BSE outbreak in cattle (http://www.cdc.gov). According to The National Creutzfeldt-Jakob Disease Surveillance Unit, by June 2014 it had killed 177 people in the United Kingdom, and 52 elsewhere. This essay will focus on the possible causes, effects, and treatment for this

The aggregation of prion proteins and their transmissibility from one cell to another has been shown to be evident (Cushman et al.; Goedert et al. 2010), therefore strongly suggesting that these events may play a role in pathogenesis for many diseases, including both AD and PD. While none of these diseases is infectious in an identical way as

While dysfunction of prion proteins remains the most widely accepted etiology of BSE, the USDA suggests there may be two other possible theories that could better explain the manifestation of BSE: the virino theory and the virus theory. However, both theories pale in comparison to the robust evidence in support of the prions theory. A major argument that works against both the virino theory and virus theory is that throughout several studies, the use of various treatments known to damage or inhibit nucleic acids have had no effect on the transmissibility of BSE. Interestingly, prion proteins lack nucleic acids – making them an excellent candidate as the infectious agent responsible for the development of bovine spongiform encephalopathy.

2. Ozonolysis of compound Z yields the products shown below. What is the structure of Z?

protein and it deletes a small amount of DNA from the CFTR gene. I am going to explain what

Now prions work in an odd way, prions replicate in conformation and are a form of peptide bond (The Dangers of Cannibalism: Ellington, Andy). Then, a

Transmissible spongiform encephalopathies (TSEs) are neurodegenerative diseases that are thought to be caused by the misfolding of prion proteins. Prions are able to replicate in the absence of nucleic acids. TSEs include: scrapie, bovine spongiform encephalopathy, Creutzfeldt-Jakob disease, kuru, Gerstmann-Straussler-Scheinker disease, and Fatal Familial Insomnia. They can affect many different animals, including humans. Currently, there are no ways to diagnose, treat, or cure TSEs, as much more research is needed before these diseases are completely understood.

One of the key factors affecting a molecule’s efficiency within an organism is its individual, particular structure. A molecule’s structure depends on many different components including the type of molecule and bonding forces present. A molecule’s structure is also based on a molecule’s purpose, and a molecule’s structure can be paramount to a function performing correctly within a cell. Since molecules are assigned specific structures they are expected to perform individual tasks for the body which allow an organism to function properly as a whole. The unique structure of proteins, water, and nucleic acids is essential to many imperative functions that allow an organisms to survive and prosper.

Bettelheim, Brown, Campbell and Farrell assert that polypeptide chains do not extend in straight lines but rather they fold in various ways and give rise to a large number of three-dimensional structures (594). This folding or conformation of amino acids in the localized regions of the polypeptide chains defines the secondary structure of proteins. The main force responsible for the secondary structure is the non-covalent

Molecular chaperones stabilize unfolded or misfolded proteins until native conformations have been obtained to promote cell survival during and after stress conditions. They do not change or add to the folding principles encoded by a protein because polypeptide chains inherently carry within them all the information that is necessary for achieving the native state of a protein. Instead, they optimize the folding process by stabilizing folding intermediates and are involved in every aspect of proteome maintenance including de novo folding, refolding of stress-induced misfolded proteins, and targeting proteins for degradation (Hartl 2009, Hartl 2011). Chaperones, many of which are induced or upregulated only during stress conditions, work in cooperative networks when protein-aggregate concentration