Gated Transport Flashcards
newly synthesized proteins must ____ properly and undergo various ______
fold, modifications
what does it mean when a protein is folded co-translationally?
folded immediately as proteins are synthesized
what is a molten globule?
quick formation of an approximate secondary structure from the almost there state
what are molecular chaperones?
proteins needed to assist in protein folding
what is HSP?
heat shock protein, they help proteins fold and shield hydrophobic patches (can get messed up if exposed to water)
what is HSP60 and HSP70
HSP70 then HSP60
HSP70- associates as a polypeptide emergence?
HSP60- barrel like structure that holds unfolded proteins helps it refold
what happens to proteins that are not properly folded?
try to refold correct but if not gets degraded
how do you know when a protein is properly folded?
does not have hydrophobic patches
what is a proteasomes?
for protein degradation, many copies in cytosol and nucleus, stack of 4 rings, central core where degradation occurs and caps that gate for proteins marked for degradation
what is the polyubiquitin chain?
marks a protein to be degraded, gets recognized by proteasome cap
what is ubiquitination?
putting a ubiquitin onto a protein
what is the E2/E3 complex (ubiquitan ligase)?
puts a ubiquitin onto the bad protein
what is E2 (ubiquitin-conjugated enzyme)?
holds onto ubiquitin thats gonna be put onto protein.
what is E1?
ubiquitin activating enzyme. takes in ubiquitin and interacts with E2 to put it on
whats an additional function of ubiquitin?
DNA repair, endocytosis, histone regulation, regulate protein function
what are prion diseases?
2 ways to fold a protein (good and bad), bad influences the good to change shape and they are resistant to degradation
what are FG repeats?
line nuclear pore complex, unstructured, permeability to large molecules, and act as a docking site for nuclear cargo receptors.
what is the nuclear localization signal?
tag on a protein that says it needs to go in/out of nucleus, has + charged residues from arg and lys, can be located anywhere on protein, binds to nuclear import receptors/ nuclear import adaptor proteins
what is gtp hydrolysis?
GTP turns into GDP, phosphate group leaves
what are g-proteins?
protein that can bind to GTP
describe ran mediated nuclear import/export
- an active G-protein will undergo GTP hydrolysis which turns the GTP into GDP
- the g-protein is now inactive and the GDP will leave
- another GTP will come and attach to the g-protein turning it active again
what is GTPase?
enzymatic activity that hydrolyzes GTP to GDP
what is guanine nucleotide exchange factor?
kicks GDP off of g-protein, only exists in the nucleus. binds to chromatin
nuclear import receptor only binds to ____ not ____
GTP, GDP