Protein Transport + Secretion

Question 1

How many proteins does the cell membrane have?

Answer 1

300

Question 2

How many proteins does the outer membrane have?

Answer 2

50

Question 3

How many proteins does the periplasm have?

Answer 3

100

Question 4

T4S

Answer 4

Conjugate pilus

Question 5

Fla/T3S

Answer 5

Effector/toxins

Question 6

CU

Answer 6

Pilus

Question 7

T2S

Answer 7

Hydrolytic enzymes, toxins, type IV pilus

Question 8

Components of Sec system

Answer 8

-Leader peptide on preprotein (SIGNAL)
- Signal recognition particle (SRP)

Question 9

Preprotein

Answer 9

Not in shape yet

Question 10

Cleavage site

Answer 10

leader peptide cleaved once transported across membrane

Question 11

N-terminal

Answer 11

start of protein/peptide
–> recognizes leader
–> trafficks to SecYEG to interact and be transported across membrane

Question 12

Chaperone

Answer 12

SecB

Question 13

Membrane complex

Answer 13

SecYEG

Question 14

ATPase

Answer 14

SecA

Question 15

SecB 2 modes of binding

Answer 15

Premiscuous binding to polypeptide
- specific binding partner (SecA)

Question 16

What happens during promiscuous binding to polypeptide?

Answer 16

• keeps protein in translocation competent state
• prevent from aggregation + folding before IM

Question 17

What happens during specific binding to SecA

Answer 17

• delivers preprotein to SecA, engages with SecB

Question 18

SecYEG

Answer 18

• membrane translocase
• pore in hydrophyllic channel
• allows delivery to periplasm or IM

Question 19

Goal of SecYEG

Answer 19

deliver mature protein to periplasm in unfolded state

Question 20

Charge of N-domain, C-terminal and H-domain

Answer 20

N - basic charge
C - neutral
H - hydrophobic region

Question 21

2 options for prepeptide

Answer 21

1. stay in membrane
2. released to periplasm

Question 22

TAT

Answer 22

Twin-agenine translocation