Stx Protein, Shigella dysenteriae:
Stx protein, also known as Shiga toxin protein, is a toxin produced by the bacterium Shigella dysenteriae. Shigella dysenteriae is a pathogenic bacterium that is responsible for the infectious disease known as shigellosis or bacillary dysentery. The Stx protein is one of the main virulence factors of this bacterium.
The Stx protein belongs to the family of AB5 toxins, which are characterized by their structure consisting of a pentamer or ring of five receptor-binding B subunits and an enzymatically active A subunit. The B subunits are responsible for binding to specific receptors on the surface of target cells, while the A subunit carries out the toxin's enzymatic activity.
Once the Stx protein is released by Shigella dysenteriae into the human host, it targets and binds to specific receptors found in the intestines and other tissues. This binding allows the toxin to enter cells and inhibit the protein synthesis necessary for normal cellular function. The Stx protein causes damage to the cells lining the intestines, leading to the characteristic symptoms of shigellosis, such as severe diarrhea, abdominal pain, fever, and vomiting.
The presence of Stx protein in the body is detected through laboratory testing of stool samples. Identification of Stx protein is crucial for confirming the diagnosis of shigellosis and differentiating it from other causes of gastrointestinal illness.
In summary, Stx protein is a critical virulence factor produced by Shigella dysenteriae, responsible for causing shigellosis. Understanding its structure and mode of action is crucial for the development of targeted therapies and vaccines to combat this infectious disease.
