Crystal Structure of Reovirus Polymerase λ3
Yizhi Jane Tao and Stephen C. Harrison
from: Segmented Double-stranded RNA Viruses: Structure and Molecular Biology (Edited by: John T. Patton). Caister Academic Press, U.K. (2008)
The reovirus polymerase and those of other viruses belonging to the Reoviridae function within the confines of a protein capsid to transcribe the tightly packed dsRNA genome segments. The crystal structures of the reovirus polymerase λ3 and its initiation and elongation complexes have been determined by X-ray crystallography. The λ3 structure shows a fingers-palm-thumb core, similar to those of other viral polymerases, surrounded by major N- and C-terminal elaborations, which create a cage-like structure, with four channels leading to the catalytic site. These four channels serve as the inlet and outlet for the template, substrate, dsRNA product, and mRNA transcript during replication and transcription. A 5' cap binding site has been found on the surface of λ3, suggesting that λ3 may employ a template retention mechanism by which attachment of the 5' end of the plus-sense strand facilitates insertion of the 3' end of the minus-sense strand into the template channel read more ...