Huntington's Disease Flashcards

1
Q

Is fragmentation of an unfolded protein reversible?

A

No

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2
Q

What are the three routes an unfolded protein could take?

A

Form an intermediate required for the final structure, aggregate disorderly or fragment.

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3
Q

What did Anfensen’s experiment with RNAase demonstrate?

A

The inherent nature of peptides to fold into the correct structure.

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4
Q

What is the effects of urea on proteins?

A

Break H bonds

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5
Q

What is the effect of Mercaptoethanol on proteins?

A

Reduce S-S bonds.

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6
Q

What are the three proposed mechanisms via which proteins fold?

A

Framework, nucleation and hydrophobic collapse.

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7
Q

What does the framework model of protein folding propose?

A

Some segments of the peptide are predisposed to form beta and some alpha structures. These form a framework for protein folding.

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8
Q

What does the nucleation model of protein folding propose?

A

One part of the protein forms a secondary structure that it is predisposed to and folding propagates outwards.

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9
Q

What does the hydrophobic collapse model of protein folding propose?

A

Hydrophobic interactions form first and the remainder forms around it.

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10
Q

What do the wells of an energy funnel represent?

A

A secondary structure that is not native and not most favourable so is reversed.

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11
Q

What are the two stable states a protein make take?

A

The native state and the amyloid fibril (beta-rich) state, which may be more stable that the native conformation.

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12
Q

In an amyloid, is the entire protein misfoled?

A

No, only part become beta-rich. The remainder is often in its native state.

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13
Q

What are the two major components of the kinetics of fibril formation?

A

Lag phase (monomer-seed) and elongation.

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14
Q

How are kinetics of fibril formation altered if we start with a nucleus/seed?

A

The lag phase is shortened.

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15
Q

What is one treatment option for amyloids formed from transthyretin?

A

Thyroid-like molecules that stabilise the tetramer state.

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16
Q

In how many proteins does poly-Q lead to disease?

A

9 proteins

17
Q

How does polyQ expansion occur?

A

CAG regions are likely to be duplicated during replication. This causes polyQ expansion over generations.

18
Q

What number of glutamine repeats be tolerated before disease occurs?

A

37

19
Q

What disease can the Huntingtin protein lead to?

A

Huntington’s disease

20
Q

What disease can Atrophin 1 lead to?

A

Dentatorubral-pallidolusysian atrophy.

21
Q

What disease can the androgen receptor lead to?

A

Spinal bulbar muscular dystrophy

22
Q

What disease can Ataxin 1, 2, 3, 6 and 7 lead to?

A

Spinocerebellar Ataxias 1, 2, 3, 6, 7

23
Q

What disease can the TATA-binding protein lead to?

A

Spinocerebellar Ataxia 17

24
Q

What does 9 proteins susceptible to polyQ related disease have in common?

A

Tendency to form beta sheets
PolyQ expansion
Tolerance of up to 37 polyQ.

25
Q

Which axon of the Huntingtin gene is affected by polyQ expansion?

A

Axon 1

26
Q

What protein is usually found in areas of Amyloid accumulation?

A

Ubiquitin

27
Q

Can GFP-u be ubiquitinated in the presence of huntingtin aggregates?

A

No

28
Q

Give an example of a healthy protein that amyloid aggregates can interact with?

A

transcriptional coactivators, e.g. CBP

29
Q

What tag is used to measure beta-sheet formation and aggregation?

A

Thioflavin T, which binds to beta-sheets

30
Q

How does polyQ expansion lead to misfolding?

A

Decreases stability

31
Q

Does polyQ expansion increase or decrease CM?

A

Decrease

32
Q

What is the effect of heat shock protein 70 on polyglutamine Q78 effects?

A

Decreases effects of polyQ78 by binding to hydrophobic domains of misfolded proteins and preventing interaction.

33
Q

What is the effect of trehalose on huntingtin?

A

Stabilisation and treatment of Huntington’s.