Bovine Spongiform Encephalopathy:
A look at the molecular level
COMPETENCY 208.5.2: AMINO ACIDS AND PEPTIDE BONDS, PROTEIN STRUCTURE
BY: MELANIE MANGER
Bovine Spongiform Encephalopathy
Commonly know as Mad Cow Disease Although the United States has strict standards when it comes to food, BSE is absolutely an international issue
A cow will ingest a food (usually a protein) that is contaminated, we as humans then in turn become infected when we eat food products made up from that particular cow
Prions are an infectious agent that cause a protein in the body to fold abnormally form. Those proteins then replicate within the body and lead to brain degeneration and ultimately will cause ...view middle of the document...
We rely on our diet to provide us with the recommended amounts of these acids. Leucine is one of those 10 essential amino acids. Leucine is non-polar (meaning that it has no charge) and hydrophobic (meaning that it avoids contact with water). The carbon side chain increases the level of hydrophobicity.
BSE: The Molecular Level
Leucine is usually found buried in the folds of a protein. “A protein fold is defined by the way the secondary structure elements of the structure are arranged relative to each other in space” (S. Al Karadaghi). Should a protein not fold appropriately, the shape will change and the function of that protein will be lost
What is the function of Leucine? “Leucine is one of three essential amino acids that increase muscle mass and help muscles recover after exercise. It also regulates blood sugar and supplies the body with energy” (A. Darrow). Leucine has also been found to promote healing.
BSE: The Molecular Level Dehydration & Hydrolysis
Dehydration is the process by which 2 amino acids are joined together The first amino acid will lose a OH from the carboxyl group The second amino acid will lose Hydrogen (H) from the amine group The OH and H that were lost, will combine to form water (H2O) Now that each amino acid has let go of those molecules, there is now a place for peptide bonding to occur
Hydrolysis is the process by which the peptide bond between 2 amino acids is broken down Water (H2O) is added, breaking the site where bonding had occurred The OH attaches itself to the carboxyl group of the first amino acid, while the H attaches itself to the amine group of the second amino acid It is at this point that there are now two complete amino acids
BSE Diagram of Dehydration and Hydrolysis
BSE: The Molecular Level Protein structure
RNA will determine the sequence of amino acids in a polypeptide. This sequence is known as primary structure. Secondary structure is the shape that the polypeptide takes as a result of hydrogen bonding. There are 2 different shapes, alpha helix and beta pleated sheet. Tertiary structure is the 3 dimensional shape that occurs due to a series of interactions between the R groups.
Hydrophilic R groups will form hydrogen bonds Hydrophobic R groups will tend to fold in towards the center of the protein, while Van der Waals interactions will keep them closely packed together.
Ionic bonds will form between R groups of opposing charge.
Disulfide bond (bridges) is a strong bond that occurs between the 2 sulfhydryl groups in cysteine
Quaternary structure is where several polypeptides interact with one another to take their final shape (and function). Hemoglobin is one example of quaternary structure. In hemoglobin, 4 polypeptides interact with one another to give way to the final 3 dimensional shape.
BSE: The Molecular Level Diagram of Protein Structures
BSE: The Molecular Level Protein Misfolding and Aggregation