4r71

Publication Abstract from PubMed

Upon infection of Escherichia coli by bacteriophage Qbeta, the virus-encoded beta-subunit recruits host translation elongation factors EF-Tu and EF-Ts and ribosomal protein S1 to form the Qbeta replicase holoenzyme complex, which is responsible for amplifying the Qbeta (+)-RNA genome. Here, we use X-ray crystallography, NMR spectroscopy, as well as sequence conservation, surface electrostatic potential and mutational analyses to decipher the roles of the beta-subunit and the first two oligonucleotide-oligosaccharide-binding domains of S1 (OB1-2) in the recognition of Qbeta (+)-RNA by the Qbeta replicase complex. We show how three basic residues of the beta subunit form a patch located adjacent to the OB2 domain, and use NMR spectroscopy to demonstrate for the first time that OB2 is able to interact with RNA. Neutralization of the basic residues by mutagenesis results in a loss of both the phage infectivity in vivo and the ability of Qbeta replicase to amplify the genomic RNA in vitro. In contrast, replication of smaller replicable RNAs is not affected. Taken together, our data suggest that the beta-subunit and protein S1 cooperatively bind the (+)-stranded Qbeta genome during replication initiation and provide a foundation for understanding template discrimination during replication initiation.

Structural basis for RNA-genome recognition during bacteriophage Qbeta replication.,Gytz H, Mohr D, Seweryn P, Yoshimura Y, Kutlubaeva Z, Dolman F, Chelchessa B, Chetverin AB, Mulder FA, Brodersen DE, Knudsen CR Nucleic Acids Res. 2015 Dec 15;43(22):10893-906. doi: 10.1093/nar/gkv1212. Epub, 2015 Nov 17. PMID:26578560^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.