Chapter 6

Question 1

What is the result of amino acid tautomerization?

Answer 1

The double bond prevents free rotation

Question 2

What side of the alpha carbon is the psi angle?

Answer 2

C-terminal side

Question 3

What side of the alpha carbon is the phi angle on?

Answer 3

N-terminal side

Question 4

What are secondary structures?

Answer 4

Local structures with repeating favorable psi/phi angles that are stabilized by hydrogen bonds along the protein backbone

Question 5

What are the phi/psi angles of an alpha helix?

Answer 5

Phi = -60
Psi = -45

Question 6

How many residues are in each turn of an alpha helix?

Answer 6

3.6

Question 7

How much does an alpha relix rise per residue?

Answer 7

1.5 angstrom

Question 8

What is the dipole of an alpha helix?

Answer 8

Negative (COO-) pointing up
Positive (NH3+) pointing down

Question 9

What are the phi/psi angles for beta-strands?

Answer 9

Phi = -120
Psi = 120

Question 10

How many residues per turn are in beta-strands?

Answer 10

~2

Question 11

How much do beta-strands rise per turn?

Answer 11

3.5 angstrom

Question 12

What are random coils?

Answer 12

Secondary structures (not helices or sheets) that don’t conform to a recurring pattern

Question 13

What drives protein folding?

Answer 13

Hydrophobic Interactions

Question 14

What is alpha-keratin made of?

Answer 14

7 residue repeats where 1 and 4 are nonpolar (Rich in Cys)

Question 15

What is collagen made up of?

Answer 15

Repeats of Gly-Pro-Pro/HyP

Question 16

What is needed to make hydroxyproline?

Answer 16

Ascorbic acid (Vitamin C)

Question 17

What direction does collagen form?

Answer 17

Left-handed individual strands to make a right-handed complex when strands are connected

Question 18

What can predict localization within a protein?

Answer 18

Hydropathy plots