Proteins, Protein Folding and Modifications Flashcards
What are the 4 non-covalent forces involved in Protein Folding?
Hydrophobic Interactions
Hydrogen bonds
Ionic or electrostatic interactions
van der Waals Forces
Besides contributing to protein folding what else do the 4 non-covalent forces do?
prevent protein degredation
Why did Dr. Dickerson equate the 4 non-covalent protein folding forces to Velcro?
Because they all work together and you can change one of them and not necessarily compromise its stability! Like pulling up the corner on a piece of velcro - it still sticks together
What drives Hydrophobic Interactions?
Water!
Not nonpolar hydrophobic groups
It would rather interact with itself than hydrophobic groups that would cause it to form an ordered structure…and water likes chaos!
True or False
A polar substance in water will dissolve very easily
True
It has a better interaction with water than water has with itself!
Which bond type is the biggest player in secondary and tertiary structure?
Hydrogen Bonds - surprise!
Is a hydrogen bond stronger or weaker when it’s bent?
weaker
Is a hydrogen bond stronger or weaker when it’s linear?
stronger
How do electrostatic interactions work?
Interactions between charged groups (pos and neg that attract) - important for stabilization and binding of charged ligands and substrates
In Electrostatic Interactions why are the charged groups located on the outer surfaces of the protein?
so they can interact with water molecules
Why are non-charged or non-polar groups located on the innermost portion of a protein?
Because they don’t want to interact with water
What is the weakest of the noncovalent forces?
Van der Waals Forces
What is the purpose of Van der Waals Forces?
to contribute to the folded structure
Why wouldn’t you want Van der Waals forces in secondary structure?
Because they are weak forces and you need strong hydrogen bonding to stabilize alpha helices and beta sheets!
What are chaperones?
Helper proteins that help to fold and unfold using ATP - one chaperone on one side helps to unfold and the other on the other side may help to fold again…
Does protein folding happen without chaperones?
Yes but they faciliate the process they don’t catalyze it
Clinical Correlation
What is a prion?
a protein that acts as an infectious agent in it’s misfolded form
What are Transmissible Spongiform Encephalophaties caused by?
Bad Prions - the bad prions act as a template and convert good prions to bad prions - that’s why it happens so quickly and the nervous system shuts down.
How does one develop bad prions to begin with?
Infectious agent/process (most common)
Can be hereditary
Spontaneous mutation