The basic structure of a protein is a polypeptide chain made up of amino acids linked together by peptide bonds.
Key points:
- Amino acid structure:
Each amino acid has:- An amino group (-NH₂)
- A carboxyl group (-COOH)
- A hydrogen atom (H)
- A variable side chain (R group) that determines the amino acid’s properties
- Peptide bond formation:
- Amino acids are linked by peptide bonds between the carboxyl group of one amino acid and the amino group of the next.
- This forms a linear chain called a polypeptide.
- Levels of protein structure:
- Primary structure: Sequence of amino acids in a chain
- Secondary structure: Local folding into α-helix or β-pleated sheet stabilized by hydrogen bonds
- Tertiary structure: 3D folding of the entire polypeptide
- Quaternary structure (if present): Association of multiple polypeptide chains
In short:
The basic structure of a protein is a chain of amino acids linked by peptide bonds, which folds into specific shapes to carry out various functions in the body.