The Tertiary Structure is Stabilized by R-Group Interactions
Definition
Tertiary structure
The tertiary structure of a protein refers to the complete three-dimensional folding of a single polypeptide chain.
- The tertiary structure of a protein refers to the complete three-dimensional folding of a polypeptide chain.
- This structure is stabilized by specific interactions between the R-groups (side chains) of amino acids.
Hydrogen Bonds
- Form between slightly positive hydrogen atoms (e.g., in -OH groups) and electronegative atoms like oxygen in C=O groups.
- These bonds are weak individually but collectively provide significant stability.
Hydrogen bonds are highly sensitive to changes in temperature and pH. Extreme conditions can disrupt these bonds, leading to protein denaturation.
Ionic Bonds
Definition
Ionic bonds
- Definition:
Ionic bonds form between R-groups that carry opposite charges.
- Occur between positively charged R-groups (e.g., -NH3⁺) and negatively charged R-groups (e.g., -COO⁻).
- Stronger than hydrogen bonds but sensitive to pH changes, which can disrupt charges.
- Students often confuse ionic bonds in proteins with salt bridges in inorganic chemistry.
- Remember, in proteins, ionic bonds depend on R-group charges, which can change with pH.
Disulfide Bonds
Definition
Disulfide
Disulfide bonds are covalent bonds that form between two cysteine amino acids.
