Sorting 2 Flashcards
What are the 5 major parts of the mitochondria anatomy?
Outer Membrane, Inner Membrane, Intermembrane space, matrix and cristae(outside)
What is the movement of proteins crossing outer or inner mitochondrial membranes called?
Translocation
What directs proteins to the correct compartment in the mitochondria?
Signal Sequences
Describe the amphiphillic alpha helix
Positively charged residues on end and uncharged hydrophobic residues on the other
What are the 4 major translocators in the mitochondiral membrane?
SAM, TIM, TOM and OXA
SAM
Sorting and Assembly Machinery
TIM
Translocase of the inner membrane
Found inner membrane
TOM
Translocase of outer membrane
Insert of all nuclear encoded proteins through outer membrane
OXA
Mediates insertion of proteins synthesized in mitochondria
Two types of TIM
TIM 23
TIM 22
TIM 23
Translocates soluble proteins into matrix and helps insert membrane proteins in inner membrane
TIM 22
Mediates insertion of specific subclass of proteins
Describe the import of outer membrane proteins
- First fed through TOM
- Binds to chaperone protein
- Binds to SAM in intermembrane/outermembrane space
- Folds and inserts in to outer membrane as a porin
How is ATP used in the import of protein into the mitochondria matrix?
1) Atp is used to remove HSP70 in the cytosol prior to feeding through the TOM
2) Expenditure of ATP to add HSP70 in the matrix
3) ATP is used to fold via HSP60
____ are beta-barrels while ____ are alpha helix
Porins; amphiphilic
SRP
Signal Recognition Particle
Made up of 6 diff polypeptide proteins and a backbone of RNA molecules. Also has a large hydrophobic pocket with plenty of methiones. Helps identify that protein is for ER
What are the binding sites of the SRP?
1) Elongation binding site of the ribosome
2) Signal sequence of the protein
3) SRP Receptor
What impact does SRP binding to ribosome have on the activity?
By binding to the elongation factor binding site, it halts protein synthesis
Translocator of ER membrane has a ____ complex with ___, ____, ___ subunits.
SEC61
Alpha
Beta
Gamma
ER translocator water-filled pore opens with identification of ____ causing ____ and displaces ____.
Signal Sequence
Start-transfer signal
Plug
Translocation of soluble proteins have just ____ allowing entire protein to fall through. Transmembrane proteins have a ____ and ____
1) Start-Transfer
2) Start-transfer
3) stop-transfer
How many minimal A.A in a ER signal sequence and what is it’s property?
At least 8 Hydrophobic A.A
ER signal sequence consist of
SRP receptor and SRP(signal recog. particle)
