Bacterial Toxins Flashcards
Tetanus Toxin
Biological activity: Zinc Dependant metalloproteases
Host cell target: SNARE proteins
Vesicle trafficking: retrograde-CNS
Botulinum Toxin
Biological activity: Zinc dependent metalloproteases
Host cell target: SNARE protiens
Vesicle trafficking: PNS
Anthrax Toxin
Biological Activity: (LF) Zinc-dependent metalloprotease, (EF) Calmodulin-dependent AC
Host cell target: CMG2 and TEM8 on
Binary Toxin/CDT (C.difficile transferase)
Biological activity: (CdtA) ADP-ribosyltransferase, (CdtB) pore forming.
Host cell target: actin modification for increased adherence
TcdA and TcdB
Biological Activity: (A) Glucosyl transferase, targets RHO/RAC GTPases. (B) Cysteine protease, translocation and CROP domain
Host cell target: Carbohydrates on intestinal epithelia
Pertussis Toxin (PT)
Biological Activity: (A) ADP-ribosylation of GTP-binding protein
down regulates host cell AC, results in secretion of fluid
Host cell target: ciliated epithelial cells (mucosal or neurons)
Cholera Toxin (CT)
Biological Activity: (A) ADP-ribosyltransferase
preventing AC re-uptake, increased cAMP->activates PKA->activates CFTR->increases Cl- secretion which results in watery diarrhea.
Host cell target: (B) binds GM1 “gangliosides” that coat the intestinal epithelial cells.
Shiga-like toxin (Stx1 and/or Stx2)
Biological Activity: (A) N-glycosidase
acts by removing a specific “A” base from the 28S rRNA of the 60 S ribosomal subunit, results in termination of protein synthesis which initiates apoptosis of target cell
Host cell target: (B) glycosphingolipid “Gb3” in high receptor concentrations on kidney cells
Heat-labile Toxin (LT)
Biological Activity: (A) ADP- ribosylates AC
increases cAMP, PKA, CFTR activation (Ilke cholera!)
Heat-stable Toxin (HT)
Host cell target: direct binding to guanlyl cyclase receptors, not internalized, increases cGMP, results in CFTR activation
