The universally conserved GTPase HflX is an RNA helicase that restores heat-damagedEscherichia coliribosomes.
Dey, S., Biswas, C., Sengupta, J.(2018) J Cell Biol 217: 2519-2529
- PubMed: 29930203 
- DOI: https://doi.org/10.1083/jcb.201711131
- Primary Citation of Related Structures:  
5ZZM - PubMed Abstract: 
The ribosome-associated GTPase HflX acts as an antiassociation factor upon binding to the 50S ribosomal subunit during heat stress in Escherichia coli Although HflX is recognized as a guanosine triphosphatase, several studies have shown that the N-terminal domain 1 of HflX is capable of hydrolyzing adenosine triphosphate (ATP), but the functional role of its adenosine triphosphatase (ATPase) activity remains unknown. We demonstrate that E. coli HflX possesses ATP-dependent RNA helicase activity and is capable of unwinding large subunit ribosomal RNA. A cryo-electron microscopy structure of the 50S-HflX complex in the presence of nonhydrolyzable analogues of ATP and guanosine triphosphate hints at a mode of action for the RNA helicase and suggests the linker helical domain may have a determinant role in RNA unwinding. Heat stress results in inactivation of the ribosome, and we show that HflX can restore heat-damaged ribosomes and improve cell survival.
Organizational Affiliation: 
Structural Biology and Bioinformatics Division, Council of Scientific and Industrial Research - Indian Institute of Chemical Biology, Kolkata, India.