Mitochondria- TOM Flashcards
what are mitochondria defended from
endosymbions
describe the mitochondrial targeting signal
there is no specific sequence although they are frequently amphipathic helices
where does the energy required for translocation of proteins into the mitochondrial matrix
ATP
in which conformation are proteins transported through TOM
unfolded
why are chaperones required inside the mitochondria
refolding after translocation
what is the targeting signal for mitochondrial matrix
amphipathic helix at the N term followed by cleavage site
what is the targeting signal for mitochondrial outer membrane
amphipathic helix at the N term followed by transmembrane domain
what is the targeting signal for mitochondria inner membrane
amphipathic helix at the N term followed by a cleavage site and then a transmembrane domain
what is the targeting signal for mitochondrial integral membrane protein
hydrophobic regions overlapping transmembrane domains
what does TOM stand for
translocate of the outer membrane
what is the role of Tom20
it binds proteins with an N term amphipathic alpha helix presequence- binding in the hydrophobic groove
what is the role of Tom70
it binds proteins with multiple integrated hydrophobic sorting sequence via hydrophobic binding interactions. In addition the MSF chaperone binds tom 70. ATP hydrolysis releases MSF causing transfer of the protein to TOM20/22 receptor and then into TOM40 and smaller proteins
what is the role of TOM22
it is the receptor for charged pre sequences and docking point for tom20 and tom 70 onto the complex. it can also bind proteins on side of inter membrane space
what is the role of TOM5
transfer of proportion onto TOM40 and acts as a receptor for proteins which end up in inter membrane space
what is the signal sequence for inter membrane space proteins
amphipathic alpha helices followed by a TM domain flanked by 2 sorting signals flanked with cleavage sites
