BCM10

Question 1

average length of peptide

Answer 1

40aa

Question 2

what is conformation?

Answer 2

curvature in 3d space

Question 3

what is phi

Answer 3

rotation around N- C alpha bond

Question 4

what is psi

Answer 4

rotation around c alpha c bond

Question 5

what do phi and psi look like

Answer 5

phi - ϕ

psi - Ψ

Question 6

what is omega

Answer 6

rotatation around C-N bond not allowed
resonance
omega is 180 degrees for trans

Question 7

what is the main chain conformation defined by?

Answer 7

sequence of phi and psi angles

Question 8

what is a ramachandaran plot

Answer 8

shows allowed phi and psi angles
for all aa apart from glycine
only certain combos of tortion angles allowed

Question 9

+psi - phi

Answer 9

antiparrallel beta sheets

parallel beta sheets

Question 10

+psi +phi

Answer 10

left handed helix

Question 11

• psi -phi

Answer 11

alpha helix

Question 12

what does the secondary structure entail?

Answer 12

h bonding
alpha helix
beta pleated sheets

Question 13

what did lineus pauling and robert carey discover?

Answer 13

xray diffraction
Using standard length and bond angles
proposed beta pleated sheet and alpha helix

Question 14

describe right handed helix

Answer 14

all main chain co and nh are bonded.
side chains are extended outwards
3.6 angstrums per turn
1/5 angrstrum rise

Question 15

what does hydrogen bonding happen between?

Answer 15

carbony of ith residue and nitrgoen of i+4 th residue

Question 16

what is the optimal distance for hydrogen bonding?

Answer 16

2.8 angstrums

Question 17

describe beta pleated sheet

Answer 17

2.4 angrstrums per residue
side chains point alternatively up adn down
stabilised by main chain main chain nh/co h bonds
adjacent strands
h bonds between nh/co groupsa re far apart in aa sequence
insdie is hydrophoci
outside is hydrophillic

Question 18

how is tertiary strucutre held together?

Answer 18

by hydrophobic interactions and h bonds

Question 19

how do polar and charged amino acids interact?

Answer 19

via h bonds and ionic interaction

- gather on outsdie adn interact with water molecules

Question 20

what helps stabilise some 3d tertiary protein structures?

Answer 20

ss bonds and metal ions

Question 21

what are tertiary strucutres used to work out?

Answer 21

evolutionary origins

Question 22

what do oligimers usually exhibit?

Answer 22

rotational symmetry

dimers trimer penatmers etc

Question 23

give 2 examples of oligimers with rotational symmetry

Answer 23

lysal trna synthetase = 2 fold axis

groel = 7 fold axis

Question 24

describe alpha keeratin

Answer 24

alpha helical coiled coil
140A
left handed supercoil
hydrophobic residues clipping together

Question 25

describe the secondary tertiary and quaternary structure of haemoglobin

Answer 25

2 - alpha helix in parts
3 - metal ion stabilisation
4- hetero multimer