What is the main problem of protein translocation?
Hydrophillic proteins must transverse two hydrophobic membranes and a hydrophillic space
Proteins must be unfolded and refolded again
Proteins must pass through an extremely crowded cytoplasm
Proteins to be secreted directly after translation have a peptidase sequence at the C-terminus
Which of the following parts of the peptidase sequence are closest to the N-terminus?
The basic residues
The hydrophobic region
Peptidase cleavage recognition site
There are 1-2 basic residues in the signal sequence, but the hydrophobic sequence is variable in length
When a protein is transcribed with the Peptidase signal site, what protein binds to its hydrophobic region?
Signal Recognition Protein
Ftsy- a GTPase
SecYEG- a bacterial pore
Ftsy transfers the protein into the pore
Which of the following provide the driving force for protein translocation across the membrane
What binds to the nascent polypeptide if Post-Translational Translocation takes place?
Post-Translational Translocation sequences have a string of hydrophobic amino acids, same as in Translational Translocation
What is the role of Sec_ ?
To keep the protein in solution till it binds to SecA at the pore
To fold the protein on its way to the periplasmic more
To stop the protein folding on its way to SecC
What forces are required to get a Post-Translational Translocation through the pore?
GTPase of FtsY
ATP hydrolysis by SecB
Once inside the required membrane, what protein removes the peptide sequence?
The protein only folds after the signal sequence is cleaved