Protein Structure, Ligand Binding And Conformational Change- Amino Acid Sequence Determines Protein Structure

Question 1

What are proteins?

Answer 1

Polymers of amino acid monomers

Question 2

What are amino acids linked by?

Answer 2

Peptide bonds to form polypeptides

Question 3

How do amino acids differ in structure?

Answer 3

The R group present

Question 4

What do R groups vary in?

Answer 4

-size
-shape
-charge
-hydrogen bonding capacity
-chemical reactivity

Question 5

What are the different types of R group?

Answer 5

-basic (positively charged)
-acidic (negatively charged)
-polar
-hydrophobic

Question 6

What happens as a result from diversity of R groups?

Answer 6

There is a wide range of different functions

Question 7

What is the primary structure?

Answer 7

The sequence in which the amino acids are synthesised into the polypeptide

Question 8

What is the secondary structure?

Answer 8

Hydrogen bonding along the backbone of the protein strand

Question 9

What are the different types of secondary structures?

Answer 9

-Alpha helices
-Parallel or anti-parallel beta-pleated sheets
-turns

Question 10

What is the tertiary structure?

Answer 10

The folded polypeptide

Question 11

What is the conformation of the tertiary structure stabilised by?

Answer 11

Interactions between R groups

Question 12

What are the different types of interactions between R groups?

Answer 12

-hydrophobic interactions
-ionic bonds
-ldf
-hydrogen bonds
-disulphide bridges (covalent bonds between R groups containing sulphur)

Question 13

What is a quaternary structure?

Answer 13

They exists in proteins with two or more connected polypeptide subunits.

Question 14

What does the quaternary structure describe?

Answer 14

The spatial arrangement of the subunits

Question 15

What is a prosthetic group?

Answer 15

A non-protein unit tightly bound to a protein and necessary for it’s function

Question 16

What is the ability of haemoglobin to bind oxygen dependent upon?

Answer 16

The non-protein haem group

Question 17

What can interactions of the R groups be influenced by?

Answer 17

Temperature and pH

Question 18

How is interactions of the R group influenced by temperature?

Answer 18

Increasing the temperature disrupts the interactions that hold the protein in shape, the protein then begins to unfold, eventually becoming denatured.

Question 19

How is interactions of the R group influenced by pH?

Answer 19

The charges on acidic and basic R groups are effectived by pH. As pH increases or decreases from the optimum the normal ionic interactions between charged groups are lost which gradually changes the conformation of the protein until it becomes denatured