Protein Folding, Misfolding, and Denaturation Flashcards
A specific 3D conformation is called a
native fold
The native fold has a _____ ______ of ________ ______ within the protein.
large number of favorable interactions
What is the final folded configuration/shape of a protein determined by?
its amino acid sequence
Proteins that fail to be properly folded are ultimately
targeted for destruction
What are the steps to create a protein?
Nascent polypeptide –> folding and cofactor binding (non-covalent interactions) –> covalent modification by glycosylation, phosphorylation, acetylation, etc. –> binds to other protein subunits –> a mature functional protein is created
The 5 favorable interactions in proteins are:
- ionic bonds
- H-bonds
- van der waal’s forces
- hydrophobic effect
- disulfide bridges
What are the 3 types of non-covalent bonds needed to stabilize protein folding?
ionic bond
hydrogen bond
van der Waals
When is a protein considered misfolded?
if it cannot achieve its normal native state
Protein misfolding can be due to:
- mutations in the amino acid sequence
- a disruption of the normal folding process by external factors
Misfolded proteins typically contain
B-sheets that are organized in a supramolecular arrangement known as a cross-B structure
These B sheets rich assemblies are very ______ , very _______, and genreally _______ to ________.
stable
insoluble
resistant to proteolysis
What can increased levels of aggregated proteins in the cell lead to?
the formation of amyloid-like structures which can cause degenerative disorders and cell death
Aggregated proteins are associated with ______-_______ illnesses such as bovine ________ ________ (mad cow disease) or _______-related illnesses such as Alzheimer’s disease.
prion-related
spongiform encephalopathy
amyloid
A failure to fold properly can lead to
protein aggregation
To denature a protein is to
remove its natural characteristics
Denaturation is a process in which proteins or nucleic acids lose the
quaternary, tertiary, and secondary structure which is present in their native state
A protein is subject to change depending on its:
temperature
pH
exposure to chemicals
The weak attractions between amino acids may
alter the shape of the protein
Although the amino acid sequence ( a protein’s primary structure) ______ ____ _______ the protein’s shape may change so much that it becomes _________, in which case the protein is considered _________.
does not change
dysfunctional
denatured
When a protein becomes denatured, some of its
bonds begin to break, and it unfolds
During denaturization, bonds that held the folding ________
and bonds that created the spiral and pleats _______.Covalent bonds that held the amino acids together ______.
weaken
weaken
remain
In this unfolded state,the protein doesn’t
have it’s original nature and characteristics
Since a protein’s function is dependent on its _____, a denatured protein is no longer _________.
shape
functional
A denatured protein is not _________ active, and can’t perform its ________ function.
biologically
natural
