Protein Structure

Question 1

phi dihedral angle

Answer 1

N-C(a)

Question 2

psi dihedral angle

Answer 2

C(a)-C

Question 3

omega dihedral angle

Answer 3

C-N
cannot freely rotate due to partial double bond character

Question 4

99% of residues in a protein are what conformation?

Answer 4

trans

Question 5

pitch

Answer 5

5.4 ang
vertical distance between conseuctive turns of the helix

Question 6

which residue is cis

Answer 6

proline

Question 7

n

Answer 7

number of residues (3.6)

Question 8

d

Answer 8

distance between residues
1.5 Ang

Question 9

p =

Answer 9

n times d

Question 10

dimension of backbone

Answer 10

5-6 Ang

Question 11

backbone carbonyl of amino acid i forms ___ bond with

Answer 11

h bond with amine of i+4

Question 12

3 10 helix

Answer 12

i and i +3, more tightly would

Question 13

pi helix

Answer 13

i and i + 5, less tightly wound

Question 14

distance between residues in beta pleated sheet

Answer 14

7 angstrom

Question 15

are h bonds weaker in parallel or antiparallel beta pleated sheets

Answer 15

parallel

Question 16

coiled coil held together by

Answer 16

nonpolar interactions btwn strands

Question 17

every 3-4 AA in keratin is hydrophobic so

Answer 17

strip of contiguous hydrophobic surface area along
one face of each helical chain

Question 18

alpha keratin has a high level of

Answer 18

cysteine

Question 19

alpha keratin can be hardened by

Answer 19

introduction of disulfide cross-links within the several
levels of fiber structure

Question 20

in fibrion, almost every other residue is _____ followed by

Answer 20

glycine, serine or alanine

Question 21

every third residue in triple helical cable (collagen) is

Answer 21

glycine

Question 22

in collage triple helical cable, ___ bonds between backbone_____ and ______ protons hold chains together

Answer 22

H-bonds, carbonyls, amide

Question 23

in collagen truple helical cable, _________ are packed at the interface of the helical bundle

Answer 23

glycines

Question 24

enzyme necessary to catalyze proline –> hydroxyproline

Answer 24

ascorbic acid

Question 25

what group of hydroxyproline seems to participate in stabilizing the protein (collagen)

Answer 25

OH

Question 26

cross linking of collagen molecules require

Answer 26

lysine side chains

Question 27

AA commonly found in beta turns

Answer 27

glycine + proline

Question 28

the coiled coil is ____ handed

Answer 28

left

Question 29

most alpha-helices are ______ handed

Answer 29

right

Question 30

fibrion protein sequence

Answer 30

Gly - ala/ser - ala/ser

Question 31

collagen protein sequence

Answer 31

Gly - proline - hydroxyproline

Question 32

proteins are very insoluble at

Answer 32

pI