2pgg | pdb_00002pgg
Crystal Structure of a Birnavirus (IBDV) RNA-dependent RNA Polymerase VP1
Structural highlights
Function[RDRP_IBDV] RNA-dependent RNA polymerase which is found both free and covalently attached to the genomic RNA. May also contain guanylyl and methyl transferase activities (By similarity). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedSingle-subunit polymerases are universally encoded in both cellular organisms and viruses. Their three-dimensional structures have the shape of a right-hand with the active site located in the palm region, which has a topology similar to that of the RNA recognition motif (RRM) found in many RNA-binding proteins. Considering that polymerases have well conserved structures, it was surprising that the RNA-dependent RNA polymerases from birnaviruses, a group of dsRNA viruses, have their catalytic motifs arranged in a permuted order in sequence. Here we report the 2.5 A structure of a birnavirus VP1 in which the polymerase palm subdomain adopts a new active site topology that has not been previously observed in other polymerases. In addition, the polymerase motif C of VP1 has the sequence of -ADN-, a highly unusual feature for RNA-dependent polymerases. Through site-directed mutagenesis, we have shown that changing the VP1 motif C from -ADN- to -GDD- results in a mutant with an increased RNA synthesis activity. Our results indicate that the active site topology of VP1 may represent a newly developed branch in polymerase evolution, and that birnaviruses may have acquired the -ADN- mutation to control their growth rate. The structure of a birnavirus polymerase reveals a distinct active site topology.,Pan J, Vakharia VN, Tao YJ Proc Natl Acad Sci U S A. 2007 May 1;104(18):7385-90. Epub 2007 Apr 24. PMID:17456597[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences | ||||||||||||||||||||
