Structure and Properties of Proteins
Start with the big picture
Protein structure is described at four levels: primary structure is the amino-acid sequence; secondary structure includes locally organized forms such as α-helices and β-sheets; tertiary structure is the three-dimensional fold of one chain; and quaternary structure is the arrangement of multiple subunits. Domains and motifs are folded units associated with particular functions. Protein properties also depend on charge, solubility, and interactions with light: proteins are amphoteric, have zero net charge at their isoelectric pH, and aromatic residues absorb ultraviolet light. The topic further introduces salting-in and salting-out, denaturation and coagulation, chaperone-assisted folding, and the consequences of misfolding. Together, these concepts provide a framework for understanding how protein structure relates to behavior.
What you'll learn
- Distinguish primary, secondary, tertiary, and quaternary protein structure.
- Describe how domains and motifs relate to protein function.
- Explain how pH and amino-acid composition influence protein properties.
- Summarize how salts, heat, and chemical agents affect protein folding and solubility.
- Identify the roles of chaperones and the consequences of protein misfolding.
Continue your study
Work through the complete notes and reinforce the topic with the study tools available in the full lesson.
