Final answer:
Protein folding is assisted by chaperones and governed by attractive interactions such as hydrophobic interactions, ionic bonding, hydrogen bonding, and disulfide linkages.
Step-by-step explanation:
Protein folding is critical to its function. It was originally thought that the proteins themselves were responsible for the folding process. Only recently was it found that often they receive assistance in the folding process from protein helpers known as chaperones (or chaperonins) that associate with the target protein during the folding process. They act by preventing aggregation of polypeptides that make up the complete protein structure, and they disassociate from the protein once the target protein is folded.
The shape and stability of the tertiary structure of proteins are determined by four major types of attractive interactions. These interactions include:
- Hydrophobic interactions: Nonpolar amino acids tend to be buried inside the protein, away from water. This interaction helps to fold the protein into a compact structure.
- Ionic bonding: Charged amino acids can form ionic bonds by exchanging electrons. These electrostatic attractions also contribute to the folding of proteins.
- Hydrogen bonding: Hydrogen atoms in polar amino acids can form hydrogen bonds with other hydrogen or oxygen atoms. These bonds stabilize the folded structure of proteins.
- Disulfide linkages: Two cysteine amino acids can form a covalent bond called a disulfide linkage. These bonds provide extra stability to the protein structure.