HUANG - LECTURE 1 Flashcards
what are the different functions of proteins
what are the advantages of compartmentalization
how does subcellular fractionation work
how does differential centrifugation work
how does zonal/isopycnic centrifugation work
what was the meselson-stahl experiment
how does fluorescence microscopy work
potential issue is that the fluorescent protein fusion might disrupt the native protein structure
co-localization helps you figure out if you’re targeting the right thing
how does FISH work
fluorescence in situ hybridization
uses fluorescently labeled DNA probes to identify and locate specific DNA sequences on chromosomes
at what points in time can protein targeting happen
co or post translationally
what is the order of protein targeting to organelles
what are the types of topogenic sequences present in nascent peptides
where are the signals and are they removed in the ER, mito, chloro, peroxisome and nucleus?
what techniques are used to identify mitochondrial targeting sequences
deletion mutagenesis and site directed mutagenesis
then examined by fluorescence microscopy
also swapping signal sequences
how does movement and recognition of proteins work for protein targeting?
the movement of proteins to membrane is driven by diffusion, there is no cytoskeleton movement
proteins can move alone or with a binding partner
the recognition of the correct membrane is determined by receptors, which identify the peptide itself or the binding partner
how does the catch and release system work for the ER targeted proteins
SRP (signal recognition particle) binds the signal sequence (on the N terminus)
this slows down translation
SRP binds it receptor and is released, and translation picks up
another binding site (such as on the pore) is required to avoid diffusion back into the cytosol
what are some energy gradients that give translocation directionality
how does membrane insertion of ER targeted proteins work
happens co translationally
hydrophobic start transfer sequence, and hydrophobic stop transfer sequence
enters the translocation channel in the ER membrane
threaded through, until the signal peptide gets the stop transfer sequence and cleaves the start transfer sequence
the signal sequence is cleaved and degraded
and now there is an ER membrane protein
how does post translational targeting happen, with the example of mitochondrial targeting
