Protein folding and neurodegenerative disease Flashcards
Which amino acid does transcription always start with?
methionine
Which post-transitional modification targets the protein for destruction?
Ubiquitination
Where do the following proteins get degraded: - long half-life - membrane proteins - extracellular proteins
lysosome
Where do the following proteins get degraded: - short half-life - key metabolic enzymes - defective proteins
proteosome
What is the primary structure of a protein
amino acid sequence
What is the secondary structure of a protein
local folding (e.g alpha helix or beta pleated sheet)
What is the tertiary structure of a protein?
long-range folding will have a single polypeptide chain “backbone” with one or more protein secondary structures, the protein domains E.g. beta plypeptide of heme
What is the quaternary structure of a protein
multimeric organisation Protein quaternary structure is the number and arrangement of multiple folded protein subunits in a multi-subunit complex - e.g. RBC
What is the supramolecular structure of a protein?
large scale assemblies
What contributes to proteostasis?
- synthesis - folding - processing - assembly - trafficking - localisation - degradation
What can a disruption in proteostasis lead to?
many diseases e.g. alzeimers
What is the primary structure of an amino acid?
Which amino acods have positively charged R groups?
lysine, arginine, histidine
Which amino acids have negatively charged r groups
aspartate, glutamate
Which amino acids have nonpolar, aromatic r groups?
phenylalanine, tyrosine, tryptophan
Which amino acids have polar, uncharged r groups?
proline, asparagine, glutamine, serine, threonine, cysteine
Which amino acids have nonpolar, aliphatic r groups?
glycine, alanine, valine, leucine, methionine, isoleucine
What would a conservative mutation infer?
The amino acid change will still have similar properties of r group
How does the cellular environment effect protein folding?
environment is hisghly crowded
- increased tendenc for proteins to aggregate
What are molecular chaperones?
any protein that interacts with, stabilises or helps another protein acquire its functionally active confirmation, without being present in its final structure
What do chaperones bind to?
selectively bind to short stretches of hydrophobic amino acids
What are the proteome-maintenance functions of chaperones?
- de novo folding
- refolding
- oligomeric assembly
- protein trafficking
- proteolytic degradation
Describe how chaperones work (in stages)
- newly created polypeptide emerges ribosome - a chaperon molecule will immediately bind
- as more polypeptide is made, more chaperone molecules will bind
- The polypeptide will then exit the ribosome, covered with chaperone molecules
- They create a cove for a protein to make its confirmational shape and then will dissociate