Tertiary structure of fibrous proteins

Question 1

what secondary structure dominates the structure of fibroin

Answer 1

beta sheets

Question 2

what are alpha-keratins enriched for

Answer 2

cysteine and alanine

Question 3

what are the structures of alpha-keratins reinforced by ?

Answer 3

disulfides

Question 4

what does “harder: refer to in a keratin structure?

Answer 4

more disulfides

Question 5

what are the 2 chains in a dimer twisted into in an alpha ketain

Answer 5

left-handed coiled coil

Question 6

what percent of protein mass in mammals is collagen

Answer 6

25-35%

Question 7

where is collagen found

Answer 7

skin bones teeth

Question 8

what is collagen composed of? (in terms of structure)

Answer 8

regular, helical structure

Question 9

what is tthe handedness of collagen

Answer 9

left handed

Question 10

how many residues per turn of collagen

Answer 10

3

Question 11

what do 3 collagen chains assemble into

Answer 11

right handed super helix

Question 12

what is the primary structure of collagen characterized by?

Answer 12

glycine-proline-hydroxyproline

Question 13

where does hydrogen bonding occur in collagen

Answer 13

between strands, not within them

Question 14

what are collagen chains rich in?

Answer 14

glycine, proline, 4-hydroxyproline, 5-hydroxylyysine

Question 15

when does hydroxylation of 4-hydroxyproline occur?

Answer 15

after protein synthesis

Question 16

what is required in the reaction of forming 4-hydroxyproline

Answer 16

ascorbic acid (vitamin c)

Question 17

where does 5-hydrxoylysine appear in collagen

Answer 17

intervals

Question 18

what is required in the formation of 5-hydroxylysine?

Answer 18

vit c

Question 19

how does cross-linking occur in collagen?

Answer 19

lysine, hydroxylysine, and histidine

Question 20

what is consistent to all soluble globular proteins?`

Answer 20

mixtures of secondary structure + irregular
hydrophobic cores
closely packed interior
maximum H-bonds in the interior

Question 21

what are the differences between different soluble globular proteins

Answer 21

secondary structure composition
prosthetic groups
disulfide presence

Question 22

where does extensive H-bonding occur in soluble globular proteins

Answer 22

within not between

Question 23

what is the handedness of connections between beta strands in soluble globular proteins

Answer 23

right handed

Question 24

what is conserved better, structure or sequence?

Answer 24

structure

Question 25

what are supersecondary structures

Answer 25

motifs and domains

Question 26

what are motifs

Answer 26

recognizable combinations of secondary structure that appear in a number of different proteins

Question 27

what are domains

Answer 27

discrete, independently folded compact units within a polypeptide

Question 28

can domains include motifs?

Answer 28

yes

Question 29

what are two motifs that satisfy hydrophobic burial

Answer 29

betaalphabeta or alphaalpha

Question 30

what is the complex motif made from the b-a-b loop motif

Answer 30

alpha/beta barrel

Question 31

what is a leucine zipper

Answer 31

coiled coil containing two alpha with leucines in the helix:helix interface

Question 32

what is the handedness of a leucine zipper

Answer 32

left handed superhelix