HflX is a ribosome-splitting factor rescuing stalled ribosomes under stress conditions
HflX is a ribosome-splitting factor rescuing stalled ribosomes under stress conditions
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DOI：
10.1038/nsmb.3103
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发表时间：
2015-10
期刊：
影响因子：
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通讯作者：
Yanqing Zhang;C. S. Mandava;W. Cao;Xiaojing Li;Dejiu Zhang;Ningning Li;Yixiao Zhang;Xiaoxiao Zhang;Yan Qin;K. Mi;Jianlin Lei;S. Sanyal;N. Gao
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文献类型：
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作者：
Yanqing Zhang;C. S. Mandava;W. Cao;Xiaojing Li;Dejiu Zhang;Ningning Li;Yixiao Zhang;Xiaoxiao Zhang;Yan Qin;K. Mi;Jianlin Lei;S. Sanyal;N. Gao
Adverse cellular conditions often lead to nonproductive translational stalling and arrest of ribosomes on mRNAs. Here, we used fast kinetics and cryo-EM to characterizeEscherichia coliHflX, a GTPase with unknown function. Our data reveal that HflX is a heat shock–induced ribosome-splitting factor capable of dissociating vacant as well as mRNA-associated ribosomes with deacylated tRNA in the peptidyl site. Structural data demonstrate that the N-terminal effector domain of HflX binds to the peptidyl transferase center in a strikingly similar manner as that of the class I release factors and induces dramatic conformational changes in central intersubunit bridges, thus promoting subunit dissociation. Accordingly, loss of HflX results in an increase in stalled ribosomes upon heat shock. These results suggest a primary role of HflX in rescuing translationally arrested ribosomes under stress conditions.
