toxin anti-toxin systems Flashcards
toxins
produce a toxic and deadly effect in cells
antitoxins
reverse effects of toxic
primary role of antitoxins is to
bind to the toxin tightly, preventing toxin activity from occurring
secondary role of antitoxins is to
provide transcriptional repression of the toxin- reducing the conc in the cell
antitoxins are …… in the absence of toxins
disordered
if the cell doesn’t have anti-toxins it will
die
why is TA system important
ensures cell maintain the plasmid encoding the opera- cells that lose the plasmid are quickly killed
example of an AT system in e.coli
CcdA/CcdB system
Ccd
control of cell death
CcdB
toxin- holds open ds gate- so no replication can take place
CcdA
antitoxin
target of CcdB
DNA gyrase
DNA gyrase
cause a ds break in DNA to allow another ds DNA to pass through the gate- painting supercoiling and untangling DNA during replication and division
how does CcdA work
changes conformation of CcdB to prevent its interaction with gyrase
which antibiotic works like CcdB
ciprofloxcin
