Molecular basis of cobalamin-dependent RNA modification
Name
Dowling-2016-Molecular basis of cobalamin-depe.pdf
Size
4.2 MB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Miles, Zachary D.
Maiocco, Stephanie J.
Elliott, Sean J.
Bandarian, Vahe
Dowling, Daniel P.
Koehrer, Caroline
Drennan, Catherine L.
Date Issued
September 2016
Journal
Nucleic Acids Research
Publisher
Oxford University Press
Citation
Dowling, Daniel P. et al. “Molecular Basis of Cobalamin-Dependent RNA Modification.” Nucleic Acids Research (2016): gkw806.
Version
Final published version
Abstract
Queuosine (Q) was discovered in the wobble position of a transfer RNA (tRNA) 47 years ago, yet the final biosynthetic enzyme responsible for Q-maturation, epoxyqueuosine (oQ) reductase (QueG), was only recently identified. QueG is a cobalamin (Cbl)-dependent, [4Fe-4S] cluster-containing protein that produces the hypermodified nucleoside Q in situ on four tRNAs. To understand how QueG is able to perform epoxide reduction, an unprecedented reaction for a Cbl-dependent enzyme, we have determined a series of high resolution structures of QueG from Bacillus subtilis. Our structure of QueG bound to a tRNA[superscript Tyr] anticodon stem loop shows how this enzyme uses a HEAT-like domain to recognize the appropriate anticodons and position the hypermodified nucleoside into the enzyme active site. We find Q bound directly above the Cbl, consistent with a reaction mechanism that involves the formation of a covalent Cbl-tRNA intermediate. Using protein film electrochemistry, we show that two [4Fe-4S] clusters adjacent to the Cbl have redox potentials in the range expected for Cbl reduction, suggesting how Cbl can be activated for nucleophilic attack on oQ. Together, these structural and electrochemical data inform our understanding of Cbl dependent nucleic acid modification.
MIT Department
Massachusetts Institute of Technology. Department of Biology
Massachusetts Institute of Technology. Department of Chemistry
Terms of Use
Creative Commons Attribution-NonCommercial 4.0 International
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DOI of Published Version
https://doi.org/10.1093/nar/gkw806
