文章基本信息

标题：Assembly of Qβ viral RNA polymerase with host translational elongation factors EF-Tu and -Ts
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作者：Daijiro Takeshita ; Kozo Tomita
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2010
卷号：107
期号：36
页码：15733-15738
DOI：10.1073/pnas.1006559107
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Replication and transcription of viral RNA genomes rely on host-donated proteins. Q{beta} virus infects Escherichia coli and replicates and transcribes its own genomic RNA by Q{beta} replicase. Q{beta} replicase requires the virus-encoded RNA-dependent RNA polymerase ({beta}-subunit), and the host-donated translational elongation factors EF-Tu and -Ts, as active core subunits for its RNA polymerization activity. Here, we present the crystal structure of the core Q{beta} replicase, comprising the {beta}-subunit, EF-Tu and -Ts. The {beta}-subunit has a right-handed structure, and the EF-Tu:Ts binary complex maintains the structure of the catalytic core crevasse of the {beta}-subunit through hydrophobic interactions, between the finger and thumb domains of the {beta}-subunit and domain-2 of EF-Tu and the coiled-coil motif of EF-Ts, respectively. These hydrophobic interactions are required for the expression and assembly of the Q{beta} replicase complex. Thus, EF-Tu and -Ts have chaperone-like functions in the maintenance of the structure of the active Q{beta} replicase. Modeling of the template RNA and the growing RNA in the catalytic site of the Q{beta} replicase structure also suggests that structural changes of the RNAs and EF-Tu:Ts should accompany processive RNA polymerization and that EF-Tu:Ts in the Q{beta} replicase could function to modulate the RNA folding and structure.
关键词：complex structure ; RNA replicase ; translational factors