Brittany Mascarenhas (ID: 20471654)
Tuesday October 23, 2012
In an organism, almost every dynamic function relies on proteins. A protein's function is a direct result of their intricate folding, the simplest level of which is the sequence of amino acids. (Fitzpatrick et al, 2011). Each amino acid has a unique characteristic because of the physical and chemical properties in their side chains, which affects the function of a protein. (Alberts et al, 2010). After a cell synthesizes a polypeptide chain, it will take on the structure of a specific protein and fold through the formation of bonds between the various side chains. (Fitzpatrick et al, 2011). Proteins can share four levels of structure: primary, secondary and tertiary or quaternary forms. (Reece, 2011).
The primary structure of a protein contains the distinct chain of amino acids. (Reece, 2011). The secondary structure refers to segments of polypeptide chains which are folded or coiled, as a result of hydrogen bonding on the polypeptide backbones. (Reece, 2011). The electrognetaive oxygen and nitrogen atoms both have a partial negative charge and attach to the weakly positive hydrogen atom. (Reece, 2011). There are two secondary structures that can form: an ɑ helix, with hydrogen bonding every fourth amino acid, and a β pleated sheet when the polypeptided backbones bond to form parallel or anti-parallel sheets.(Reece, 2011). The tertiary structure creates the overall shape of a polypeptides produced by interactions between the amino acid’s side chains. (Fitzpatrick et al, 2011). This interaction plays an important role in stabilizing the protein.(Reece, 2011). The non polar side chains will move, away from water, to the core of the protein, as a because of hydrophobic interactions (Reece, 2011). Once the non polar amino acids are close by they are held together by van der Waals interactions. Other interactions include more hydrogen...
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