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49 Cards in this Set
- Front
- Back
What are the main three cellular targets |
Cell envelope Periplasmic space Extracellular environment |
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What is enteric |
Lives in the gut |
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What does E. Coli cause |
Diarrhoea and UTIs |
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How many proteins does E. Coli encode |
4288 |
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Where are the majority of E. Coli proteins targeted to |
Cytoplasmic membrane- 896 Outer membrane- 313 Periplasm- 139 |
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What accounts for around 40% of the soils composting activity |
Streptomyces coelicolor |
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What are prolific producers if antibiotics |
Streptomyces |
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How many proteins does S. coelicolor encode |
7825 |
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What does 25% of S. coelicolor encoded proteins target |
Cytoplasmic membrane (1119) Extracellular environment (819) |
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What are cellular targets |
Secreted proteins Intrinsic membrane proteins Peripheral membrane proteins Lipoproteins |
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What are the properties of the secretion pathway |
Conserved in all organisms Transports unfolded proteins |
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What are the properties of the twin arginine translocase |
Found in 50% bacteria, plants and archaea Transports folded proteins |
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Where is the Sec pathway found |
All domains of life |
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What does the Sec pathway catalyse |
Catalysed export of unfolded proteins with an N terminal signal sequence |
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How long is the sec signal sequence |
Around 20 amino acids with tripartite structure |
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Is the sec signal conserved |
No conserved sequence motifs |
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How can you predict the sec signal sequences |
Using signalP |
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What is secretion specific chaperone |
Bonds to basic regions of the protein rather than the sognal sequence |
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What does SecB maintain |
Maintains Sec substrates in an unfolded state |
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What does SecB deliver |
Delivers substrates to SecA for translocation |
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What binds to the signal sequence of the sec substrate as it emerges from the ribosome |
Signal recognition particle |
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What are most transmembrane proteins exported by |
SRP signal recognition particle |
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What is SecYEG |
Forms the protein channel or pore |
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What is SecA |
It is the motor protein that drives translocation of the protein through SecYEG |
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What 3 Secs are essential and highly conserved in bacteria |
SecY SecE SecA |
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What Sec are non essential |
SecG |
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How many membranes does SecY span |
10 |
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What does SecE do |
Acts as a clamp to hold the two halves of SecY together and keep the pore closed |
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How many membranes does the SecG span |
Spans the membrane twice with N and C termini in the outer face of the membrane |
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What does SecG undergo |
Cycle of topology inversion |
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What is SecA |
It is soluble and dimeric |
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When is SecA active |
Only active when bound to SecY |
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What does SRP- ribosome provide |
The energy to insert multiple TM helices |
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What is YidC |
It is essential for Sec translocation if membrane proteins |
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What does SlyD and Dnak chaperones interact with a wide range of Tat substrates |
This may prevent degradation of the signal sequence or mis targeting to sec |
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What does insertion of cofactors require |
Specific chaperones |
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What does proof reading involve |
Substrate specific chaperones that prevent Tat binding before correct assembly |
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What is required for TMAO reductase |
Insertion of molybdenum cofactor absolutely required |
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What does TorD bind |
Binds signal peptide |
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What is a heterodimer transported to |
To the Periplasm as an active enzyme complex |
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What is the minimal Tat translocase made up of |
TatA and TatC |
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What is TatB mostly absent from |
Gram positive bacteria but is required for activity in gram negative |
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What is TatA |
Forms the protein channel or pore |
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What is Tat(B)C involved in |
Involved in signal recognition |
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What is TatC |
Recruits and binds TatA |
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What does Tat(B)C bind |
The Tat substrate signal sequence and then the TatC- substrate complex binds TatA |
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What does TatA need to function |
Tat(B)C |
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How does the signal sequence remain bound to TatC |
Translocation |
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What drives Tat |
Generated by the PMF deuces Tat transport |