Structure of proteins II Flashcards

1
Q

how are beta strands held together

A

interchain hydrogen bonding of the backbone C=O and N-H groups

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

antiparallel beta sheets

A

adjacent strands run in opposite directions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

parallel beta sheets

A

adjacent strands run in same directions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what are reverse turns stabilized by

A

hydrogen bonding, salt bridges, metal ions, disulfide bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is often found in reverse turns

A

proline and glycine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what is tertiary structure

A

3D folded structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

prosthetic groups

A

organic molecules that are permanently bound to the protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

apoproteins

A

lack prosthetic group whilst the final functional molecule is said to have the native strucutre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what is unqiue about myoglobin

A

has high affinity for oxygen
heme group contains an Fe2+ ion that is required for oxygen binding
secondary structural elements are all alpha helices

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what are some ways that the native structure of proteins can be denatured

A

incrased temp
detergents
pH extreme
agents like urea and guanidinium hydrochloride

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

how does denaturing work

A

disrupt non-covalent bonds that maintain folded conformation of the protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

how does protein foldign occur

A

favored pathways in a cooperative manner

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what is protein folding driven by in an aqueous environement

A

strong tendency of hydrophobic residues to be excluded from water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

forces that contribute to stabilizing protein structure

A

cystine disulfide bridges
hydrogen bonding
ionic interactions
hydrophobic forces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

where are salt bridges and hydrogen bonding usually taking place

A

internal portion of molecule or interfaces btwn polypeptide chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

where are hydrophobic amino acids suually

A

interior

17
Q

prion

A

proteiancous infection partical

18
Q

examples of prion diseases

A

creutzfeldt jakob
kuru
vCJD

19
Q

how is kurur transmitted

A

funeral rites involving cannablism

20
Q

how is CJD spread

A

spontaneous and inherited

21
Q

how is vCJD spread

A

tranmitted

BSE-infected cow

22
Q

what secondary structure predominates in prions

A

beta sheet

23
Q

what aggregates in parkinsons

A

alpha synuclein

24
Q

Hb is a tetramer of what

A

2 alpha-globin and 2 b-globin subunits

25
Q

what does the Hb tetramer form form assocation of

A

2 alpha-beta dimers

26
Q

what are the cohesive forces acting in Hb

A

hydrophbic, hydrogen bonding, salt bridge

27
Q

when does Hb not bind O2 efficiently

A

low O2 conc

28
Q

where does Hb bind O2 efficiently

A

high O2 conc

29
Q

when does myoglobin bind O2 qwith high affinity

A

low O2

30
Q

what is the shape of Hb binding curve

A

sigmoid

31
Q

what is the shape of myoglobin binding curve

A

hyperbolic

32
Q

what is the tight conformation of deoxygenated Hb

A

T form

33
Q

what is happening during the T form

A

valine residue partially blocks the O2 binding site

34
Q

what is the high affinity Hb form

A

R-form

35
Q

how does 2,3 BPG affect Hb

A

stabilizes T form, reduces o2 affinity

36
Q

what happens when H+ bindings specific histdiines in Hb

A

form salt bridges, stabilizes T form, promotes O2 release