In staphylococcal food poisoning and toxic shock syndrome, exotoxins produced by the pathogens function as superantigens, which can activate all T cells. 

#Id: 2431

#Unit 3. Fundamental Processes

Rho binds to a sequence within the transcript upstream of the site of termination. This sequence is called a rut site (an acronym for rho utilization).

#Id: 2432

#Unit 3. Fundamental Processes

When the RNA polymerase reaches the termination site, rho first freezes the structure of the polymerase and then invades the exit channel to destabilize the enzyme, causing it to release the RNA.

#Id: 2433

#Unit 3. Fundamental Processes

Pausing by the polymerase at the site of termination allows time for rho factor to translocate to the hybrid stretch and is an important feature of termination.

#Id: 2434

#Unit 3. Fundamental Processes

The efficiency of a rut site increases with the length of the C-rich/G-poor region.

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#Unit 3. Fundamental Processes

Rho is a member of the family of hexameric ATP-dependent helicases. Each subunit has an RNA-binding domain and an ATP hydrolysis domain. 

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#Unit 3. Fundamental Processes

Rho has an N-terminal, RNA-binding domain and a C-terminal ATPase domain. A hexamer in the form of a gapped ring binds RNA along the exterior of the N-terminal domains. The 5’ end of the RNA is bound by a secondary binding site in the interior of the hexamer.