Module 7: Global Regulation

• catabolite repression: shut off lac operon when glucose is available
• 3 components of catabolite repression:

  1. phosphotransferase system
  2. adenylated cyclase
  3. cyclic AMP receptor protein
• what part of the phosphotransferase system is phosphorylated during glucose transport?

  IIA-glc protein, phosphorylates glucose when present
• what does IIA-glc protein do when no glucose is present?

  activates adenylate cyclase
• what does adenylated cyclase do when activated?

  catalyzes conversion of ATP to cyclic-AMP
• what is cyclic AMP?

  signal molecule that indicates glucose isn't present
• what type of regulation is cyclic AMP receptor protein?

  positive regulator synthesized in inactive state
• what happens when cAMP binds to cyclic AMP receptor protein?

  causes conformational change to bind before lac promoter and recruit RNA polymerase
• label parts of catabolite repression

  A) adenylated cyclase

  B) allolactose

  C) inactive

  D) activated

  E) cyclic AMP receptor protein

  F) recruits RNA polymerase

  
• heat shock response: alternative sigma factor, prepares cell to survive adverse temperatures
• how are heat shock proteins expressed?

  always present but increase at high temps
• types of heat shock proteins:

  1. regulators
  2. molecular chaperones: protein synthesis/folding
  3. proteases: remove denatured proteins
• what is the heat shock master regulator?

  sigma H
• how is rpoH translation regulated?

  by control of translational initiation via RNA structure
• how do high temperatures regulate rpoH translation?

  high temperatures melt secondary structure so ribosome can bind more readily and increase transcription
• how are protein chaperones regulated?

  regulation by control of protein stability, destabilizes rpoH
• how do high temperatures regulate proteins chaperones?

  at high temps more proteins denature and require chaperones, freeing up rpoH and increasing transcription of heat shock genes
• label rpoH translation regulation

  A) molecular chaperone

  B) degredation

  C) heat shock genes

  D) low temperature

  E) high temperature

  
• label heat shock process

  A) rpoH gene

  B) secondary structure

  C) molecular chaperones

  D) rpoH

  E) degredation

  F) melted

  G) increase translation of sigma H

  H) sigma H recognizes polymerase

  I) increase transcription of heat shock genes

  
• 2 component regulators: sensor kinase and response regulator
• sensor kinase: enzyme in membrane that binds environmental signal and phosphorylates
• where does sensor kinase transfer phosphate?

  to response regulator
• response regulator: binds to kinase, activates or represses transcription
• phosphatase: removes phosphate from regulator and decreases response
• label 2 component regulators

  A) environmental signal

  B) sensor kinase

  C) response regulator

  D) phosphatase

  
• what does luciferase do in bioluminescence qourum sensing?

  reduce long chain aldehyde, consuming oxygen and producing light
• what do luxCDE proteins do in bioluminescence quorom sensing?

  remove fatty acids to turn into aldehydes for luciferase
• what occurs at low bacteria populations in bioluminescence qourum sensing?

  LuxR activators is synthesized and autoinducer diffuses out of cell
• what occurs at high bacteria populations in bioluminescense quorom sensing?

  AHL activates LuxR and transcription of lux operon occurs