01Protein Structure & Function
Primary structure
This section covers the amino acid sequence of a polypeptide and how it influences protein shape and function.
The primary structure is the particular sequence of amino acids in a polypeptide chain. Adjacent amino acids are joined by covalent peptide bonds.
Genetic information determines the order in which amino acids are assembled during protein synthesis. Different proteins therefore have different amino acid sequences.
The sequence affects how the polypeptide can fold and which interactions can develop later. Changing even part of the sequence can consequently alter the final three-dimensional shape and may affect protein function.
- Sequence: the order of the amino acids in the chain.
- Number: different proteins can contain very different numbers of amino acids.
- Peptide bonds: covalent links join neighbouring amino acids.