HflX is a ribosome-splitting factor rescuing stalled ribosomes under stress conditions

分类： 生物学 >> 生物物理学 >> 生物物理、生物化学与分子生物学 提交时间： 2016-05-11

Zhang, Yanqing Cao, Wei Li, Ningning Zhang, Yiudao Zhang, Xiaoxiao Lei, Jianlin Gao, Ning Mandava, Chandra Sekhar Sanyal, Suparna Li, Xiaojing Mi, Kaixia Zhang, Dejiu Qin, Yan

摘要： Adverse cellular conditions often lead to nonproductive translational stalling and arrest of ribosomes on mRNAs. Here, we used fast kinetics and cryo-EM to characterize Escherichia coil HflX, 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.

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