Microbiology Block E- Lecture 2

Front 1

What are the main three cellular targets

Back 1

Cell envelope

Periplasmic space

Extracellular environment

Front 2

What is enteric

Back 2

Lives in the gut

Front 3

What does E. Coli cause

Back 3

Diarrhoea and UTIs

Front 4

How many proteins does E. Coli encode

Back 4

4288

Front 5

Where are the majority of E. Coli proteins targeted to

Back 5

Cytoplasmic membrane- 896

Outer membrane- 313

Periplasm- 139

Front 6

What accounts for around 40% of the soils composting activity

Back 6

Streptomyces coelicolor

Front 7

What are prolific producers if antibiotics

Back 7

Streptomyces

Front 8

How many proteins does S. coelicolor encode

Back 8

7825

Front 9

What does 25% of S. coelicolor encoded proteins target

Back 9

Cytoplasmic membrane (1119)

Extracellular environment (819)

Front 10

What are cellular targets

Back 10

Secreted proteins

Intrinsic membrane proteins

Peripheral membrane proteins

Lipoproteins

Front 11

What are the properties of the secretion pathway

Back 11

Conserved in all organisms

Transports unfolded proteins

Front 12

What are the properties of the twin arginine translocase

Back 12

Found in 50% bacteria, plants and archaea

Transports folded proteins

Front 13

Where is the Sec pathway found

Back 13

All domains of life

Front 14

What does the Sec pathway catalyse

Back 14

Catalysed export of unfolded proteins with an N terminal signal sequence

Front 15

How long is the sec signal sequence

Back 15

Around 20 amino acids with tripartite structure

Front 16

Is the sec signal conserved

Back 16

No conserved sequence motifs

Front 17

How can you predict the sec signal sequences

Back 17

Using signalP

Front 18

What is secretion specific chaperone

Back 18

Bonds to basic regions of the protein rather than the sognal sequence

Front 19

What does SecB maintain

Back 19

Maintains Sec substrates in an unfolded state

Front 20

What does SecB deliver

Back 20

Delivers substrates to SecA for translocation

Front 21

What binds to the signal sequence of the sec substrate as it emerges from the ribosome

Back 21

Signal recognition particle

Front 22

What are most transmembrane proteins exported by

Back 22

SRP signal recognition particle

Front 23

What is SecYEG

Back 23

Forms the protein channel or pore

Front 24

What is SecA

Back 24

It is the motor protein that drives translocation of the protein through SecYEG

Front 25

What 3 Secs are essential and highly conserved in bacteria

Back 25

SecY

SecE

SecA

Front 26

What Sec are non essential

Back 26

SecG

Front 27

How many membranes does SecY span

Back 27

10

Front 28

What does SecE do

Back 28

Acts as a clamp to hold the two halves of SecY together and keep the pore closed

Front 29

How many membranes does the SecG span

Back 29

Spans the membrane twice with N and C termini in the outer face of the membrane

Front 30

What does SecG undergo

Back 30

Cycle of topology inversion

Front 31

What is SecA

Back 31

It is soluble and dimeric

Front 32

When is SecA active

Back 32

Only active when bound to SecY

Front 33

What does SRP- ribosome provide

Back 33

The energy to insert multiple TM helices

Front 34

What is YidC

Back 34

It is essential for Sec translocation if membrane proteins

Front 35

What does SlyD and Dnak chaperones interact with a wide range of Tat substrates

Back 35

This may prevent degradation of the signal sequence or mis targeting to sec

Front 36

What does insertion of cofactors require

Back 36

Specific chaperones

Front 37

What does proof reading involve

Back 37

Substrate specific chaperones that prevent Tat binding before correct assembly

Front 38

What is required for TMAO reductase

Back 38

Insertion of molybdenum cofactor absolutely required

Front 39

What does TorD bind

Back 39

Binds signal peptide

Front 40

What is a heterodimer transported to

Back 40

To the Periplasm as an active enzyme complex

Front 41

What is the minimal Tat translocase made up of

Back 41

TatA and TatC

Front 42

What is TatB mostly absent from

Back 42

Gram positive bacteria but is required for activity in gram negative

Front 43

What is TatA

Back 43

Forms the protein channel or pore

Front 44

What is Tat(B)C involved in

Back 44

Involved in signal recognition

Front 45

What is TatC

Back 45

Recruits and binds TatA

Front 46

What does Tat(B)C bind

Back 46

The Tat substrate signal sequence and then the TatC- substrate complex binds TatA

Front 47

What does TatA need to function

Back 47

Tat(B)C

Front 48

How does the signal sequence remain bound to TatC

Back 48

Translocation

Front 49

What drives Tat

Back 49

Generated by the PMF deuces Tat transport