@article{3cbce145d3094c738d2c235060eaef55,
title = "Epoxyqueuosine Reductase QueH in the Biosynthetic Pathway to tRNA Queuosine Is a Unique Metalloenzyme",
abstract = "Queuosine is a structurally unique and functionally important tRNA modification, widely distributed in eukaryotes and bacteria. The final step of queuosine biosynthesis is the reduction/deoxygenation of epoxyqueuosine to form the cyclopentene motif of the nucleobase. The chemistry is performed by the structurally and functionally characterized cobalamin-dependent QueG. However, the queG gene is absent from several bacteria that otherwise retain queuosine biosynthesis machinery. Members of the IPR003828 family (previously known as DUF208) have been recently identified as nonorthologous replacements of QueG, and this family was renamed QueH. Here, we present the structural characterization of QueH from Thermotoga maritima. The structure reveals an unusual active site architecture with a [4Fe-4S] metallocluster along with an adjacent coordinated iron metal. The juxtaposition of the cofactor and coordinated metal ion predicts a unique mechanism for a two-electron reduction/deoxygenation of epoxyqueuosine. To support the structural characterization, in vitro biochemical and genomic analyses are presented. Overall, this work reveals new diversity in the chemistry of iron/sulfur-dependent enzymes and novel insight into the last step of this widely conserved tRNA modification.",
author = "Qiang Li and R{\'e}mi Zallot and Mactavish, {Brian S.} and Alvaro Montoya and Payan, {Daniel J.} and You Hu and Gerlt, {John A.} and Alexander Angerhofer and {De Cr{\'e}cy-Lagard}, Val{\'e}rie and Bruner, {Steven D.}",
note = "Funding Information: This work was supported by NIH grant R01 GM041916. Funding Information: This work was supported by the National Institutes of Health (Grant R01 GM70641 to V.d.C.-L. and SDB and P01 GM118303 to J.A.G.). The authors acknowledge the Advanced Photon Source, particularly the staff and resources at GM/CA CAT. GM/CA@APS has been funded in whole or in part with Federal funds from the National Cancer Institute (ACB-12002) and the National Institute of General Medical Sciences (AGM-12006). This research used resources of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. The authors also thank Martin McLauglin and Wilfred A. van der Donk for providing guidance and the plasmid isc-pBADCDF for in vivo maturation of metalloenzymes. The LC–MS analyses were performed by Furong Sun at the Mass Spectrometry Laboratory, a Service Facility from the School of Chemical Sciences at University of Illinois at Urbana-Champaign. Publisher Copyright: {\textcopyright} 2021 American Chemical Society.",
year = "2021",
month = oct,
day = "26",
doi = "10.1021/acs.biochem.1c00164",
language = "English (US)",
volume = "60",
pages = "3152--3161",
journal = "Biochemistry",
issn = "0006-2960",
publisher = "American Chemical Society",
number = "42",
}