Proteins-Higher Orders of structure

Question 1

a-helix

Answer 1

H bonds nearby. Between amide and carbonyl groups.
Disrupted by proline, bulky, like charges

3.6 per turn, 5.4 ang. 6 ang diameter

Question 2

b-sheet

Answer 2

H bonds NOT nearby.
Parallel (bent,weak)
Antiparallel (straight H bonds, stronger)

Question 3

Random coil

Answer 3

Irregular arrangement of polypeptide chain

Question 4

Strong helix formers

Answer 4

Ala and Val

Question 5

Helix breakers

Answer 5

Pro and Gly

Question 6

B-turns

Answer 6

180 degrees over 4 AAs.
H bind from carbonyl oxygen to amide proton 3 residues down.
Proline forces turns, glycine present at position 3 often

Question 7

Domain

Answer 7

Sufficient to perform a chemical or physical task. Tertiary structure

Question 8

Tertiary and Quarternary structure stabilized by

Answer 8

Hydrophobic, hydrophilic, salt bridges, hydrogen bonds, disulfide bonds

Question 9

X-ray crystallography

Answer 9

Determine secondary and tertiary structure.
Pros: no size limit
Cons: difficult for membrane proteins, can’t see hydrogen’s

Question 10

NMR

Answer 10

Determine secondary and tertiary structures.
Pros: can see many hydrogen’s and don’t have to crystallize.
Cons: difficult for insoluble proteins, works best with small proteins

Question 11

Endosome -lysosomes pathway

Answer 11

Degrades extracellular and surface proteins

Question 12

Uniquitin-proteasome pathway

Answer 12

Degrades proteins from cytoplasm, nucleus, and ER

Question 13

Collagen

Answer 13

Fibrous in ECM, holds cells together, provides thermal stability and strength. Adhesion.
Gly-X-Y
Hydroxypro and Lys occur post translation

Question 14

Adds hydroxyl groups to Pro and Lys in collagen

Answer 14

Metal containing enzymes, happens post translationally

Facilitates intrachain H bonds and stabilizes

Question 15

Lysyl Oxidase

Answer 15

Catalyze formation of covalent cross links between collagen and elastin. Uses Cu2+

Question 16

A-ketoglutarate,O2, Fe2+, ascorbate (vitamin c)

Answer 16

Required to add hydroxyl groups to collagen.

Question 17

Ascorbic Acid deficiency

Answer 17

Scurvy. Formation of stable triple helix in collagen is I,paired. Bruise like discolorations, gum and teeth problems

Question 18

Cu2+ deficiency

Answer 18

Menkes Disease

Question 19

Ehlers-Danlos syndrome

Answer 19

Heterogenous group of connective tissue disorders from heritable defects in metabolism of fibrillar collagen molecules

Question 20

Osteogenesis imperfecta

Answer 20

Collagen type 1. Brittle bones

Question 21

Elastin.

Answer 21

Fibrous. lungs, arteries, ligaments, skin, and bladder.

Help blood flow in arteries and abundant in large vessels such as aorta

Question 22

Elastin cross links

Answer 22

Tropoelastin is basic soluble unit.

Formed between amino groups of side chains and catalyze by Lysyl oxidase

Question 23

a-1 antitrypsin

Answer 23

—Inhibits elastase that destroys elastin of alveolar walls of lungs.
—Protects for emphysema and COPD.
—Smoking inactivates it by oxidizing Met resided 351 and 358