title: RNA-dependent RNA polymerases from Flaviviridae.
abstract: Viral genome replication in Flaviviridae is carried out by a virally encoded RNA-dependent RNA polymerase (RdRp). These viruses initiate the RNA synthesis via a de novo mechanism that differs from the primer-dependent mechanism used by Picornaviridae. Like all polymerases, the structure of Flaviviridae RdRps resembles a right hand with characteristic fingers, palm, and thumb domains. Structural features that distinguish Flaviviridae RdRps from other polymerases are a large thumb domain and a C-terminal motif that encircles the active site. This domain arrangement restricts the volume of the template-binding channel, allowing only single-stranded RNA to enter the active site. While this closed form of the polymerase is ideal to stabilize a de novo initiation complex, significant conformational changes are expected to accommodate the elongation complex containing the RNA duplex product.
authors.affiliation: Department of Biochemistry & Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch at Galveston, TX 77555-0647, USA. kychoi@utmb.edu
authors.forename: Kyung H
authors.initials: KH
authors.lastname: Choi
authors.forename: Michael G
authors.initials: MG
authors.lastname: Rossmann
mesh_terms: D018360:Crystallography, X-Ray; D018067:Flaviviridae / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000378:metabolism; D011487:Protein Conformation; D012367:RNA, Viral / Q000096:biosynthesis; D012324:RNA-Dependent RNA Polymerase / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D012367:RNA, Viral; D006160:Guanosine Triphosphate; D012324:RNA-Dependent RNA Polymerase