Structures and Functions of Proteins: Amino acids

Question 1

Proline

Why is it unique?

Answer 1

-Has a secondary amino acid group, side chain forms rigid ring structure

-INTERRUPT THE ALPHA-HELICAL STRUCTURE (breaks it)
(glycine can also do so)

Question 2

Nonpolar amino acids

Answer 2

1) glycine
2) valine
3) alanine
4) Leucine
5) Isoleucine
6) Proline
7) Methionine

Aromatic (nonpolar):

1) Phenylalanine
2) Tryptophan
3) Tyrosine

Question 3

Uncharged, Polar amino acids

Answer 3

1) Cysteine
2) Asparagine
3) Glutamine
4) Serine
5) Threonine

Question 4

Positive Charge (Basic) amino acids

Answer 4

1) Arginine
2) Lysine
3) Histidine

Question 5

Negative Charged amino acids

Answer 5

1) Aspartate

2) Glutamate

Question 6

What amino acid synthesizes serotonin

Answer 6

Tryptophan

Question 7

How are catecholamines synthesized

Answer 7

Catecholamines:

1) Dopamine
2) Norepinephrine
3) Epinephrine

Formed from TYROSINE

Question 8

How are peptide hormones formed

Answer 8

-Cleavage from larger precursor protein

Question 9

How can Alpha-helix be interrupted?

Answer 9

1) Electrostatic repulsion or attraction between amino acids
2) Steric hinderance
3) Bulky side chains

Question 10

Quaternary Structure of Hemoglobin (Hb)

Answer 10

• Only in RBC
• Alpha beta dimers
• Hydrophobic interactions
• Weak ionic and hydrogen bonds

Question 11

Functions of Hsp 70 and Hsp 60

Answer 11

Hsp 70
-Prevents premature folding of protein

Hsp 60

• Corrects folding of cellular proteins
• Refolds
• Needs ATP

Question 12

Ubiquitin-Proteasome Complex

Answer 12

• Misfolded/defective proteins tagged by ubiquitin (Needs ATP)
• Degraded in ubiquitin-proteasome system
• Ubiquitin proteins degraded, ubiquitin recycled
• Proteasome unfolds and cuts the target protein into fragments

Question 13

Prions Disease

• Nature of disease
• Transmission

Answer 13

• Usually founds in brain

- More B-sheets (PrPsc)