Levels of protein Organization

definition

Organization of proteins

Proteins have four levels of organization: primary, secondary, tertiary, and quaternary.

1. The primary level of organization is simply the order of amino acids in the peptide chain. For example, Phe-Ala-Met-Leu-Gln-Trp-Glu-Ile.
2. Secondary structures are 2-dimensional structures formed due to hydrogen bonding between the hydrogen of amine groups and oxygen of the carbonyl groups. The two common secondary structures are the alpha-helix and the beta-sheet.
3. The tertiary structure involves the three-dimensional folding of a protein due to interactions of amino acid side chains. Where secondary structure was a result of hydrogen bonds between peptide groups, tertiary structure is a result of side chains interactions.
4. Quaternary structure involves the association of two or more polypeptides into functional proteins.