Caulobacter crescentus Hfq structure reveals a conserved mechanism of RNA annealing regulation.
Proceedings of the National Academy of Sciences of the United States of America
National Academy of Sciences
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Santiago-Frangos, A., Fröhlich, K. S., Jeliazkov, J. R., Małecka, E. M., Marino, G., Gray, J. J., Luisi, B., et al. (2019). Caulobacter crescentus Hfq structure reveals a conserved mechanism of RNA annealing regulation.. Proceedings of the National Academy of Sciences of the United States of America, 116 (22), 10978-10987. https://doi.org/10.1073/pnas.1814428116
We have solved the X-ray crystal structure of the RNA chaperone protein Hfq from the alpha-proteobacterium Caulobacter crescentus to 2.15 Å resolution, resolving the conserved core of the protein and the entire C-terminal domain (CTD). These data provide the first example of high-resolution structural information for the CTD of Hfq from any species. The structure reveals that the CTD of neighbouring hexamers pack in crystal contacts, and that the acidic residues at the C-terminal tip of the protein interact with positive residues on the rim of Hfq as recently proposed for a mechanism of modulating RNA binding. De novo computational models predict a similar docking of the acidic tip residues against the core of Hfq. We also show that C. crescentus Hfq has sRNA binding and RNA annealing activities, and is capable of facilitating the annealing of certain E. coli sRNA:mRNA pairs in vivo. Finally, we describe how the Hfq CTD and its acidic tip residues provide a mechanism to modulate annealing activity and substrate specificity in various bacteria.
Caulobacter crescentus, Bacterial Proteins, Host Factor 1 Protein, Molecular Chaperones, RNA, Bacterial, RNA, Messenger, Crystallography, X-Ray, Protein Binding, Models, Molecular, RNA, Small Untranslated
SWH and BL are funded by the Wellcome Trust (200873/Z/16/Z). This work was also supported by the NIH (R01 GM120425 to SW, F31 GM123616 to JRJ, and R01 GM078221 to JJG). KF acknowledges funding by the LMU Mentoring program of the LMU Faculty of Biology.
WELLCOME TRUST (200873/Z/16/Z)
External DOI: https://doi.org/10.1073/pnas.1814428116
This record's URL: https://www.repository.cam.ac.uk/handle/1810/291310
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