Protein folding and misfolding

Question 1

What is the importance of protein folding ?

Answer 1

It gives the protein its 3D functional shape or conformation.

Question 2

What dedicates or determines the 3D conformation of the protein ?

Answer 2

The primary structure determines the 3D conformation as the squence of the side chains of the amino acids dedicates the fold pattern of the 3D and the assembly of the subunits into quaternary strucuture.

Question 3

What are the methods of protein folding ?

Answer 3

1. Spontaneously : protein synthesized inside the body.

2. Assisted : Chaperons , Disulfide isomerase , Cis-trans isomerase.

Question 4

what is the basic mechanism behind protein folding ?

Answer 4

The hydrophobic R-groups tends to come together as non polar molecules tend to cluster as they are insoluble in water so they are present in the interior of the protein to bury hydrophobic amino acids away from water ( polar solvents ) .

Question 5

How heat affects the cell regarding protein folding and how does the cell resist that change ?

Answer 5

When the cell is exposed to sudden heat the number of misfolded protein increase as a result either chaperones or proteasomes act on these misfolded protein.

Question 6

What are the mechanisms of chaperons in correcting protein folding ?

Answer 6

1. Hsp 70 act on proteins during its formation in the ribososmes.
2. Hsp 60 ( chaperonin ) act on the protein after being fully sythensized.

Question 7

What are the mechanism of chaperonin ?

Answer 7

1. Misfolded protein enters chaperonin ( Hsp 60 ).
2. The cap ( Hsp 10 ) is attached to the cylinder and slowly the protein starts to unfold and then refold properly as the chaperonin creats a hydrophilic environment for the folding of the polypeptide.
3. The cap comes off , and the properly folded protein is released.

Question 8

What are the diseases caused by misfolding of the proteins ?

Answer 8

1. Alzheimer disease
2. Prion diseases ( mad cow disease )
3. Alpha 1 - Antitrypsin deficiency
4. Cystic fibrosis

Question 9

What are the symptoms of Alzheimer disease ?

Answer 9

1. Dementia
2. Loss of coordination
3. Rapidly progressive and fatal

Question 10

What are the causes of Alzheimer diseases /

Answer 10

It is causes by different gene mutations that lead to abnormal protein folding.

Question 11

How does abnormally folded protein affect the brain ?

Answer 11

1. There is accumulation of an abnormally folded protein in the brain called amyloid precursor protein (APP) which is critical for neuronal growth.
2. This misfolded protein will then be degraded into smaller fragments which are called beta amyloid which form plaques around neurons.

Question 11

How does abnormally folded protein affect the brain ?

Answer 11

1. There is accumulation of an abnormally folded protein in the brain called amyloid precursor protein (APP) which is critical for neuronal growth.
2. This misfolded protein will then be degraded into smaller fragments which are called beta amyloid which form plaques around neurons.