Protein Folding Flashcards
What happens when you add Urea to proteins
Dentures proteins
denatured proteins turn into polypeptide chains
losses it function
What happens when you remove Urea from proteins
Proteins fold again
Regains full original activity in SOME cases
What is needed for proteins to fold
The primary sequence is all that is needed for proteins to fold
Why is protein folding not random
Protein folding cannot be random – would take too long!
100 amino acid protein
- at least 3 possible values for each phi and psi bond
- 3198 different conformations
- assuming that the protein could explore 1013 conformations per second
This would take 3 x 10^80 years!!!!
How do proteins fold
The folding process must be ordered
* Each step involves localised folding and with stable conformations maintained
*Driven by the need to find the most stable conformation
Can existing proteins be altered
Altered conformation of a normal human protein promotes converts existing protein into a diseased state
What are amyloid fibres?
Amyloid fibrils are formed by normally soluble proteins, which assemble to form insoluble fibers that are resistant to degradation. Their formation can accompany disease and each disease is characterized by a specfic protein or peptide that aggregates.
What is the structure formed of amyloid fibres
- highly ordered with a high degree of b-sheet * core b-sheet forms before the rest of the
protein - inter-chain assembly stabilised by hydrophobic interactions between aromatic amino acid residues
Why is protein folding important
This is a vital cellular process because proteins must be correctly folded into specific, three-dimensional shapes in order to function correctly. Unfolded or misfolded proteins contribute to the pathology of many diseases.
How do you reverse protein misfolding
Treatments for these disorders remain palliative, and no available therapeutics eliminate the underlying toxic conformers.
An intriguing approach to reverse deleterious protein misfolding is to upregulate chaperones to restore proteostasis.
What are chaperones
Definition. Chaperone proteins, or molecular chaperones, are proteins that assist others to fold properly during or after synthesis, to refold after partial denaturation, and to translocate to the cellular locales at which they reside and function.
