2.7.5 Quaternary Structure

Question 1

quaternary structure

Answer 1

• the final structure of a protein that results from interactions between polypeptides
• results when polypeptides interact to form a functional multi-subunit protein
• An example of quaternary structure is hemoglobin. Hemoglobin is a protein that can transport oxygen in the blood. The hemoglobin protein is made up of four
  polypeptide chains linked together.

Question 2

protein confirmation

Answer 2

• the shape of a protein that spontaneously takes place after the polypeptide chain has been released from the RNA that directed its synthesis
• The final conformation of a protein depends on its unique sequence of amino acids (its primary structure). RNA directs the sequence of amino acids in a protein, and DNA codes for RNA.

Question 3

mutation

Answer 3

• A change in DNA
• If the DNA changes, the RNA will also be different,
  often leading to a different sequence of amino acids in the polypeptide chain. If the sequence of amino acids changes, then the conformational shape could change. When the conformational shape changes, the function of the protein can be lost.

Question 4

Imagine the strand of DNA that codes for hemoglobin is mutated so that in the resulting polypeptide, a cysteine is substituted by a glutamine. What is the most likely result in the structure of the hemoglobin?

Answer 4

• There will likely be shape changes at all levels of structure

Question 5

Proteins with multiple subunits may consist of

Answer 5

• any combination of secondary structures

Question 6

The quaternary structure of a protein

Answer 6

• consists of multiple subunits

Question 7

The conformation of a protein

Answer 7

• spontaneously occurs as the polypeptide comes off the RNA that creates it

Question 8

Quaternary structure

Answer 8

• determines the oxygen transport capabilities of hemoglobin, only applies to proteins that have multiple subunits, gives a protein a characteristic shape.