Box A-6: Hydrophobic Interactions

Some amino acids are hydrophobic. When a part of a protein, these amino acids tend to cluster on the inside of the protein in their attempt to avoid water. That pulls on the amino acid chain of the protein and contributes to the protein shape. Other amino acids are hydrophilic. They are readily soluble in water, and they tend to be on the outside of proteins. Hydrophobic interactions also affect the capability of molecules to come together. For example, enzymes are often composed of several separate proteins. The surfaces where the subunits of an enzyme touch are frequently composed of hydrophobic amino acids. Hydrophobic interactions also affect the structure of DNA and RNA. For example, a part of each nucleotide of DNA and RNA is a plana....