lecture 7

Question 1

define protein folding energy landscape theory

Answer 1

• Is a folding process
  
  • Consider it like a funnel of free energies, the top represents unfolded states
  • Polypeptides ‘fall down’ the funnel, as go down, less options for what can fold into + lower energy (more stable), until reach bottom
    Note: lowest energy conformer = highest stability

Question 2

how do fibrous proteins (e.g. A keratin) fold?

Answer 2

○ Is structural + mechanically strong
○ Found in hair, nails etc.
Its structures promotes association fo helices to form coiled coils

refer to image

Question 3

how do globular proteins fold

Answer 3

○ Most polar residues face outside + itneract with solvent, while hydrohpbic residues face inside, itneract with each other
flexibility + allow for conformational changes
○ Core made of helices + sheets,
○ E.g. Ribonuclease
Catalyses the degradation of RNA into smaller components

Question 4

describe IUPs

Answer 4

• Proteins that exist/function normally in a PARTIALLY unfolded state
  
  • Essential for cellular function
  • No structure + high flexibility, however become structured when bind to target proteins
  • Characterised by abundance of polar + lack of hydrophilic resiudes
  • Some IUPs can change shape to bind to multiple protein partners, so can be involved in multiple signalling + regulatory pathways
    E.g. Tumour suppressors

Question 5

why is protein folding/structure important?

Answer 5

• For predicting 3D structure from the sequence
• Determining biological function
• Understanding + treating protein misfolding diseases
• Production of recombinant proteins in pharmaceutical industry + biotechnology

Question 6

name 4 protein misfolding diseases

Answer 6

• Alzheimer’s
• Parkinson’s
• Huntington’s
• Prion protein disease
  -mad cow disease- not in humans

Question 7

describe prion protein disease

Answer 7

• Normal prion protein (PrPc) found in nerve cells
• If prion changes its conformation from normal to disease causing- scrapie protein (PePSc), gets into nervous system, infects other normal prions, causes nerve cell death, leaving holes behind