4R71 image
Deposition Date 2014-08-26
Release Date 2015-09-23
Last Version Date 2024-02-28
Entry Detail
PDB ID:
4R71
Title:
Structure of the Qbeta holoenzyme complex in the P1211 crystal form
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
3.21 Å
R-Value Free:
0.26
R-Value Work:
0.21
R-Value Observed:
0.21
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:Elongation factor Ts, Elongation factor Tu
Gene (Uniprot):tsf, tufB
Chain IDs:A, C
Chain Length:694
Number of Molecules:2
Biological Source:Escherichia coli
Polymer Type:polypeptide(L)
Molecule:RNA-directed RNA polymerase beta chain
Chain IDs:B, D
Chain Length:595
Number of Molecules:2
Biological Source:Enterobacteria phage Qbeta
Polymer Type:polypeptide(L)
Molecule:30S ribosomal protein S1
Gene (Uniprot):rpsA
Chain IDs:E, F
Chain Length:171
Number of Molecules:2
Biological Source:Escherichia coli
Ligand Molecules
Primary Citation
Structural basis for RNA-genome recognition during bacteriophage Q beta replication.
Nucleic Acids Res. 43 10893 10906 (2015)
PMID: 26578560 DOI: 10.1093/nar/gkv1212

Abstact

Upon infection of Escherichia coli by bacteriophage Qβ, the virus-encoded β-subunit recruits host translation elongation factors EF-Tu and EF-Ts and ribosomal protein S1 to form the Qβ replicase holoenzyme complex, which is responsible for amplifying the Qβ (+)-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 β-subunit and the first two oligonucleotide-oligosaccharide-binding domains of S1 (OB1-2) in the recognition of Qβ (+)-RNA by the Qβ replicase complex. We show how three basic residues of the β 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 Qβ 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 β-subunit and protein S1 cooperatively bind the (+)-stranded Qβ genome during replication initiation and provide a foundation for understanding template discrimination during replication initiation.

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