Protein Folding- Review Of Protein Structure

Question 1

What forces are involved in maintaining the primary structure of a protein?

Answer 1

Covalent (Peptide) Bonds

Question 2

What forces are involved in maintaining the secondary protein structure?

Answer 2

Hydrogen bonds

Question 3

What forces are involved in maintaining the tertiary structure of a protein?

Answer 3

Covalent (disulfide) bonds,
Ionic bonds, 
Hydrogen bonds, 
Van der Waals, 
Hydrophobic effect

Question 4

What forces are involved in maintaining the quaternary structure of a protein?

Answer 4

Covalent (disulphide) bonds, 
Ionic bonds, 
Hydrogen bonds, 
Van der Waals, 
Hydrophobic effect

Question 5

What amino acids are disulphide bonds created between and how can these be broken?

Answer 5

They are created between two cysteine molecules and they are broken using reducing agents.
Most proteins with disulphide bonds are secreted.

Question 6

What drives the hydrophobic effect?

Answer 6

The interaction between hydrophobic side chains due to the displacement of water.

Question 7

What causes protein denaturation?

Answer 7

Heat- because of increased vibrational energy.
pH- because it alters the ionisation state of amino acids (their charge)
Detergents or Organic solvents because they disrupt hydrophobic interactions.

Question 8

How do proteins fold?

Answer 8

The folding process must be ordered. Each step involved localised folding and with stable conformations maintained. It is driven by the need to find the most stable conformation.

Question 9

What are Amyloid fibres?

Answer 9

Misfolded, insoluble form of a normally soluble protein. This occurs when beta sheets form instead of alpha helix’s