CellBio_Intro Flashcards
when would you use subcellular fractionation?
when you want to purify organelles, in order to address questions like - organelle function, protein localization, and process reconstitution requirements
two types of gradient centrifugation
velocity gradient - separates by size
isopycnic gradient - separates by density
what three properties can you use to separate organelles
size, shape and density
why do proteins need chaperones when they can typically fold well in vitro?
cell is crowded, proteins bump and aggregate
sometimes nascent polypeptide will begin misfolding when being translated
multi-subunit constructions
what were the first chaperone proteins discovered?
heat shock proteins, or HSPs
What is the relationship between several HSPs and ATP?
They are ATP-binding proteins, and have different conformations depending on whether they are in the ATP-bound or ADP-bound state. Conformations have different properties
where do Hsp70s bind?
hydrophobic regions of unfolded proteins, stabilizes and prevents aggregation of unfolded molecule, esp nascent peptide
what’s HSP60 famous for?
Forming a capped protein folding container, with protective environment for proteins to fold in
What is Hsp90s deal?
Most abundant chaperone family, plays role in activating TFs, signaling molecules, receptors and protein kinases
Hsp100
involved in protein unfolding through ATP hydrolysis
