secondary protein structural organization

Question 1

How is amino acid sequence arranged?

Answer 1

arranged into LOCAL conformations when rotate by same amount about the alpha carbon

Question 2

What are adjacent amide planes caused by

Answer 2

B resonance contributor shows we have partial double bond character, which creates two planes

Question 3

Angles created by amide planes

Answer 3

• occurs about 2 dihedral angles (3D angles) , Ψ (psi .. aC - N) and Φ (phi… aC - C = O)
• held together by hydrogen bonds

Question 4

important bond in primary structure

Answer 4

amide bond

Question 5

important bond in secondary structure

Answer 5

hydrogen bond

Question 6

a-helix hydrogen bonds

Answer 6

Hydrogen bonds are formed in a-Helix
- NH of any amino acid (n) will be hydrogen bonded to the carbonyl oxygen of the n+4 carbon
- side chains are pointing outward and downward

Question 7

B-pleated sheet

Answer 7

• two possible orientations
• can either run anti-parallel or parallel

Question 8

anti-parallel orientation

Answer 8

• N to C across top
• N to C across bottom, but flipped around (looks like C to N)
• to join together, need a loop to cause a bend

Question 9

Parallel orientation

Answer 9

• N to C on top and bottom in same direction
• need to use a crossover, uses a chiral crossover