Group II mitochondrial introns are excised by the same mechanism as nuclear pre-mRNAs via a lariat that is held together by a 2’–5’ bond.

TLS Online TPP Program

#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.

TLS Online TPP Program

#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.

TLS Online TPP Program

#Id: 2434

#Unit 3. Fundamental Processes

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

TLS Online TPP Program

#Id: 2435

#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. 

TLS Online TPP Program

#Id: 2436

#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.

TLS Online TPP Program

#Id: 2437

#Unit 3. Fundamental Processes

The initial form of rho is a gapped ring, but binding of the RNA converts it to a closed ring.