chapter  2
Protein Structure and Properties
ByPhilip L. R. Bonner
Pages 18

Amino acids are organic acids that form the basic building blocks of a protein's structure. The vast majority of proteins in nature are constructed from amino acids containing twenty different functional groups. Individually these non-covalent forces present within a protein structure are weak but collectively they are strong enough to hold a protein in its three-dimensional shape. The attachment of the negatively charged phosphate group will cause conformational changes in the protein structure by attracting or repelling any amino acid functional group with positive or negative charges in the near vicinity. Identification of the isomeric forms of any organic compound is difficult because the properties of isomers are essentially the same. The majority of peptide bonds in proteins are in present in a trans-configuration, wherein the functional groups of amino acids attached to the a-carbon atom are on opposite sides of the peptide chain. The tertiary structure of a protein describes the final three-dimensional shape the folded protein finally assumes.