Targeting Seq's- Proteins from Cytosol to Organelles

Question 1

ER (lumen)

Answer 1

Core of 6-12 hydrophobic AA’s, often preceded by one or more basic AA’s (Arg, Lys)

Question 2

Mitochondrion (matrix)

Answer 2

Amphipathic helix, 20-50 residues in length, with Arg and Lys residues on one side and hydrophobic residues on the other

Question 3

Chloroplast (stroma)

Answer 3

No common motifs; generally rich in Ser, Thr, and small hydrophobic residues and poor in Glu and Asp

Question 4

Peroxisome (matrix)

Answer 4

PTS1 signal (Ser-Lys-Leu) at extreme C-terminus; PTS2 signal at N-terminus

Question 5

Nucleus (nucleoplasm)

Answer 5

Multiple different kinds; a common motif includes a short segment rich in Lys and Arg residues

Question 6

location of seq

Answer 6

all in N term except peroxisome (mostly in C term) and nucleus (varies)

Question 7

removal of seq

Answer 7

all except peroxisome and nucleus