Structure of the Qbeta replicase, an RNA-dependent RNA polymerase consisting of viral and host proteins.
The RNA-dependent RNA polymerase core complex formed upon infection of Escherichia coli by the bacteriophage Qbeta is composed of the viral catalytic beta-subunit as well as the host translation elongation factors EF-Tu and EF-Ts, which are required for initiation of RNA replication. We have determined the crystal structure of the complex between the beta-subunit and the two host proteins to 2.5-A resolution. Whereas the basic catalytic machinery in the viral subunit appears similar to other RNA-dependent RNA polymerases, a unique C-terminal region of the beta-subunit engages in extensive interactions with EF-Tu and may contribute to the separation of the transient duplex formed between the template and the nascent product to allow exponential amplification of the phage genome. The evolution of resistance by the host appears to be impaired because of the interactions of the beta-subunit with parts of EF-Tu essential in recognition of aminoacyl-tRNA.
Kidmose
Rune T
RT
Department of Molecular Biology, University of Aarhus, Gustav Wieds Vej 10C, DK-8000 Aarhus, Denmark.
Vasiliev
Nikita N
NN
Chetverin
Alexander B
AB
Andersen
Gregers Rom
GR
Knudsen
Charlotte R
CR
D017908:Allolevivirus / Q000201:enzymology / Q000235:genetics; D000595:Amino Acid Sequence; D001483:Base Sequence; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D017931:DNA Primers / Q000235:genetics; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D046912:Multiprotein Complexes; D010444:Peptide Elongation Factor Tu / Q000737:chemistry / Q000235:genetics; D010445:Peptide Elongation Factors / Q000737:chemistry / Q000235:genetics; D055503:Protein Multimerization; D017434:Protein Structure, Tertiary; D011777:Q beta Replicase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D055672:Static Electricity; D014764:Viral Proteins / Q000737:chemistry / Q000235:genetics
D017931:DNA Primers; D029968:Escherichia coli Proteins; D046912:Multiprotein Complexes; D010445:Peptide Elongation Factors; D011993:Recombinant Fusion Proteins; D014764:Viral Proteins; C023512:elongation factor Ts; D011777:Q beta Replicase; D010444:Peptide Elongation Factor Tu