Protein folding Flashcards
(78 cards)
What does a sigmoid curve tell us about the mechanism?
That it is cooperative
Why do secondary structures happen before tertiary structures?
Because they are closer together
What structure does the folding start with?
Primary to secondary
What is progressive stabilisation?
You start with interaction of amino acids that are very close and then go on from there so it’s progressive
What is the native structure of a protein?
The active structure which is found in for example the body and is working
Where is there more entropy ? in a folded of unfolded protein?
Unfolded because there is more disorder
Is there any entropy in the native/folded protein?
Yes but very little as it is very ordered
What are the interaction occurring in proteins to form?
Hydrogen bonds,
Hydrophobic interaction (most important)
Disulphide bonds (second most important)
Hydrophilic interaction
Can we predict structure folding based on entropy?
If entropy is decreasing then the protein is folding in the right way. If it folds in a wrong way it won’t decrease that much
What is the main driving force of protein folding?
That the proteins are emerged in water and therefor have hydrophobic interactions
Why are disulphide bonds so important?
Because it makes it more difficult to denature protein with heat
What does Leinthal’s paradox say ?
Mathematically impossible for protein folding to occur by random trying every confirmation until lowest energy is found -> it is not random
Are there formation of intermediates in protein folding?
Yes
When is a reaction favorable, when ^G is positive or negative?
Negative
What is chain conformational entropy?
Entropy of the unfolded chain
When considering entropy and enthalpy (thermodynamics) which protein is more favoured? Folded or unfolded
From a thermodynamic point of view the folded protein is favorable because it’s ^G is negative
What is the ^G in the unfolding process compared to the folding process?
Positive, therefor it is not favoured
Does the hydrophobic effect have an effect on entropy?
Yes because it causes folding and thus decreases chaos
Does enthalpy decrease or increase when the protein is folded?
Increase
What does heat disrupt in a protein?
The hydrogen bonds
Can denaturing be reversible?
Yes but not always
In most enzymes yes but not in all (complex proteins are hard to reverse denaturing)
What are the 4 denaturing agents?
Heat
pH (extreme values)-> effects the charge
Detergents (Sodiumdisulphate)
Reagents (from H bonds competing the bonds in the protein)
What kind of primary bond makes denaturing unlikely to be reversible
Primarily disulphide it is unlikely to reversible denaturation
Does denaturing effect the primary structure?
No
