1b. Primary and Secondary Protein Structure

Question 1

Primary Structure (structure, bonds)

Answer 1

structure: linear arrangement of amino acids; polypeptide backbone
bonds: covalent (peptide) bonds provide the order

just the order from N-terminus to C-terminus

Question 2

Secondary structure (structure, bonds)

Answer 2

Structure: alpha helices or beta sheets

Bonds: hydrogen bonds between backbone Carbonyl oxygen and the backbone Amine’s Hydrogen determine secondary structure

Question 3

Describe the Alpha-helical structure

Answer 3

R-groups point outward; type of secondary structure; connected by H-bonds

Question 4

Beta-pleated sheets (structure)

Answer 4

structure: 1/2 R groups point up, 1/2 R groups point down

At the edges, you see beta-turns that allow for a single polypeptide to form the beta-sheets; a beta sheet is made of many strands and turns

Question 5

What role does PROLINE play in secondary structure?

Answer 5

Proline is used to create turns in a polypeptide chain;

Found on ends of alpha-helix and in turns between strands of beta-sheet

Question 6

Tertiary structure

Answer 6

Any interaction between R groups (side chains) on the same polypeptide chain

Question 7

Quaternary structure

Answer 7

Any interaction between the 2 or more diff’t polypeptides

Question 8

Which level of protein structure involves ONLY covalent bonds

Answer 8

Primary structure

Question 9

List all levels of protein structure and key takeaway

Answer 9