Protein Structure and Function

These flashcards cover key concepts related to protein structure and function, including the functions of proteins, their diversity, interactions affecting their conformation, and the significance of chaperones and disulfide bonds.

What are the main functions of proteins?

Proteins can act as enzymes, storage proteins, structural proteins, transport proteins, signal proteins, motor proteins, gene regulatory proteins, and receptor proteins.

How do proteins attain diversity in structure and function?

Protein diversity comes from the length of polypeptide chains and the combination of the twenty different amino acids.

What types of interactions are responsible for the 3D conformation of proteins?

Covalent and non-covalent interactions, including hydrogen bonds, ionic bonds, Van der Waals forces, and hydrophobic interactions.

What role do chaperone proteins play in protein folding?

Chaperone proteins aid in proper protein folding by preventing newly synthesized polypeptides from aggregating into nonfunctional structures.

Explain how changes in temperature, pH, and salinity affect protein conformation.

Changes in these factors can disrupt the non-covalent interactions that stabilize the protein's 3D structure, leading to denaturation.

What is the significance of disulfide bonds in proteins?

Disulfide bonds stabilize the 3D conformation of proteins but do not change their structure.

What are the four common models used to visualize protein conformations?

Backbone model, ribbon model, wire model, and space-filling model.

Describe the structure of an alpha helix. What stabilizes it?

The alpha helix is stabilized by hydrogen bonds between the N-H and C=O of every fourth amino acid.

What is the difference between primary, secondary, tertiary, and quaternary protein structures?

Primary structure relates to the linear sequence of amino acids; secondary structure involves localized folding (e.g., alpha helixes, beta sheets); tertiary structure refers to the overall 3D shape; and quaternary structure consists of multiple polypeptides forming a complex.

What is a common example of a multimeric protein?

RAD51, a protein involved in the error-free repair of DNA double strand breaks.