Protein Structure and Folding

Question 0

Double covalent bond

Answer 0

Atoms share multiple electrons

Can not rotate

Question 1

Single covalent bond

Answer 1

Both attached atoms can spin freely

Question 2

Peptide bond

Answer 2

Partial double bond characteristics
Twist but cannot rotate
Polypeptides are limited in the number of shapes they can make (rigid backbone)

Question 3

4 levels of protein structure

Answer 3

1. Primary
2. Secondary
3. Tertiary
4. Quarternary

Question 4

Primary level of protein structure

Answer 4

String of amino acids covalently linked together

Concerned with nonvariable region
Read structure left->right
N Terminus->carboxyl terminus

Question 5

Secondary level of protein structure

Answer 5

Alpha helix: formed when amino acid chain wraps into a coil
Held together by hydrogen bonds
Beta sheet: forms when amino acid chain repeatedly folds back upon itself
Flat structure
Held together by hydrogen bonds
Amino acids determine whether it is formed into an alpha helix or beta sheet

Question 6

Tertiary structure of protein structure

Answer 6

Overall fold of protein
Interaction of all the secondary structural elements

How does the structure form the same way every time? -> Hydrophobic collapse

Question 7

Hydrophobic collapse

Answer 7

Hydrophobic amino acid residues are buried inside the core of the protein, shielded from the solvent (water)

Hydrophobic residues collapse away from water molecules
Hydrophilic amino acids interact with water
—>these 2 factors are the driving force of protein folding

Question 8

Globular proteins

Answer 8

Take a spheroid or “globe-like” shape, usually due to its interaction with water

Question 9

Quaternary structure of protein structure

Answer 9

Multiple proteins bound together working towards the same function
Ex: hemoglobin; collagen

Not all proteins need to have a quaternary structure