|Binding of adenine to Stx2, the verotoxin from Escherichia coli O157: H7 according to PDB 2ga4|
|Mass / length primary structure||315 + 89 amino acids (A + B)|
|Secondary to quaternary structure||Heterodimer|
|Response type||Hydrolysis of an N-glycosyl bond|
|Substrate||rRNA (60S) + H 2 O|
|Products||defective rRNA (60S)|
|Parent taxon||Escherichia coli|
The lectins Vero-Toxin 1 and Vero-Toxin 2 from Escherichia coli are also called Shiga-like-Toxin I / II (SLT I / II) or Shiga-Toxin 1/2 (Stx1 / Stx2) because of their similarity to Shiga-Toxin . It affects the eukaryotic protein synthesis by the 60S subunit of the ribosome to catalytic inactivate way. The elongation of the peptide chain is impaired by the fact that the binding of aminoacyl- tRNA to the ribosomes is prevented.
In terms of their structure and mode of action, vero toxins and Shiga toxins belong to the same group of toxins as the lectins ricin and abrin . Like these, they have two chains or subunits. It is striking that their respective subunit exactly at the same place as ricin A cleavage of the N-glycosidic bond of adenine in the 28S rRNA caused. These toxins act as specific RNA-N-glycosidases which inactivate ribosomes.
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- Bitzan M, Richardson S, Huang C, Boyd B, Petric M, Karmali MA: Evidence that verotoxins (Shiga-like toxins) from Escherichia coli bind to P blood group antigens of human erythrocytes in vitro . In: Infection and Immunity . 62, No. 8, August 1994, pp. 3337-47. PMID 8039905 . PMC 302964 (free full text).