protein folding and folding diseases Flashcards
what is a super secondary stucture
A stucture made from multiple secondary stuctures + turns and coils
What are 4 types of super secondary stuctures
helix - turn - helix
- DNA binding proteins + Ca binding proteins
Beta hairpin
- common + antiparallel
- H-bonding between strands
Greek key
- 4 antiparallel strands
Strand - helix - strand
- sheets form between strands
What are the 3 kinds of protein familys
Alpha helix families
alpha beta families
antiparallel beta families
What is a protein domain
A protein domain is a collection os super secondary stcutures which independaly fold to perform a function
- small proteins 1 domain
- larger protiens multiple domains
What are the features + examples of alpha beta families
contain both alpha and beta structures
alpha beta barrel
- hydrophobic center, comprised of 8 strand, helix pairs
What are the features + examples of alpha families
4 helix bundles
- amipiphatic structures with common side chains aggrigating
globin folds
- many alpha helix, has packing between nonadjaccent heli
What are the features + examples of antiparallel families
mostly antiparallel strands
- antiparallel barrel
- can act as a retinal binding protein
What does nature do with domains
Reuses them in many different protein stuctures
what factors are improatnt for protein structure
- hydrophobic core is most impactful
- aditional covalent bonds such as disulfide bridges
- H-bonds = non-covalent interactions
What does anfinsen’s experiment
- take native ribonuclease - denature Hbonds + disulfie bridges with urea + mercaptoethanol
- remove chemcials from solution
- air oxidise solution
- gives natuive ribonuclease without assistance
shows peptides have folding instuctures within the chain = ability to spontaneously fold
What are the steps of protein formation
- secondary structures form
- sub domains form
- ‘molten globule’ of sub domains forms partially formed domain
- forms final domain + final conformation changes
how can you unfold a protein
strong) pH change, heat change, organic solvant, detergant
weak) urea, guanidium HCL
what are chaperones and why do proteins sometimes require the,
They help assist in protein folding
85% dont need assictance / use Hsp70
15% use GroEL + GroHS
how does miss folding proteins effect brain function
PrP is a protein which can have alpha helix become beta sheet
this creates a prion = miss folded PrP
this can cause the aggrigation and missfolding of other PrP
this can lead to brain damage and death
What are some of the prion related diseases
bovine songiform encephalopathy
creutzfelt’s jacobs disease
kuru
may be associated with amyloid misfolding
- altzimers
- T2 diabetes mellitus
