Biochemistry Task 2: Amino Acids and Peptide Bonds, Protein Structure
Western Governors University
Amino Acids and Peptide Bonds, Protein Structure
The essential amino acid that I chose for this experiment is lysine. This acid has a positive charged primary amine that has about 10.5 polypetides making it have a high pKa. Because of this high pKa, the lysyl side chains are much less nucleophilic. It can become reactive if environmental effects lowers the pKa of the lysyl side chain.
The side chain does not have significant hydrophobic character because the side chain has three methylene groups. Even though the terminal amino group will be charged under physiological conditions, the a-amino group will often be exposed to the solvent but the lysines will be buried (as cited in The Biology Project et al, 2003).
There are four forces that stabilize a protein’s structure at the tertiary level. The first is hydrogen bonding, which are interactions between R groups. The second is hydrophobic interactions in which R groups tend to clump toward the center of a protein away from water. Van de Waals interactions also will result when these R groups are packed tightly between hydrophobic side branches. Hydrophobic interactions can be either polar or nonpolar. The third force that stabilized the structure are disulfide bridges. These are bonds between two cysteine R groups. The fourth force are ionic bonds between oppositely charged R groups (Wolfe, N.D.).
Bovine spongiform encephalopathy (BSE) is an infectious disease otherwise known as mad cow disease. This disease is caused by an infectious protein called a prion. The disease is transmitted by feeding cattle contaminated meat and bone meal from the remains of other cattle and sheep (Helmenstine, N.D.).
A prion is a misfolded form of a harmless protein. Misfolding means the protein takes on a different shape. The prion in BSE takes...