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Crystal structure of a class I PreQ1 riboswitch aptamer (ab13-14) complexed with a cognate ligand-derived photoaffinity probeCrystal structure of a class I PreQ1 riboswitch aptamer (ab13-14) complexed with a cognate ligand-derived photoaffinity probe
Structural highlights
Publication Abstract from PubMedThe role of metabolite-responsive riboswitches in regulating gene expression in bacteria is well known and makes them useful systems for the study of RNA-small molecule interactions. Here, we study the PreQ1 riboswitch system, assessing sixteen diverse PreQ1-derived probes for their ability to selectively modify the class-I PreQ1 riboswitch aptamer covalently. For the most active probe (11), a diazirine-based photocrosslinking analog of PreQ1, X-ray crystallography and gel-based competition assays demonstrated the mode of binding of the ligand to the aptamer, and functional assays demonstrated that the probe retains activity against the full riboswitch. Transcriptome-wide mapping using Chem-CLIP revealed a highly selective interaction between the bacterial aptamer and the probe. In addition, a small number of RNA targets in endogenous human transcripts were found to bind specifically to 11, providing evidence for candidate PreQ1 aptamers in human RNA. This work demonstrates a stark influence of linker chemistry and structure on the ability of molecules to crosslink RNA, reveals that the PreQ1 aptamer/ligand pair are broadly useful for chemical biology applications, and provides insights into how PreQ1, which is similar in structure to guanine, interacts with human RNAs. A chemical probe based on the PreQ1 metabolite enables transcriptome-wide mapping of binding sites.,Balaratnam S, Rhodes C, Bume DD, Connelly C, Lai CC, Kelley JA, Yazdani K, Homan PJ, Incarnato D, Numata T, Schneekloth JS Jr Nat Commun. 2021 Oct 6;12(1):5856. doi: 10.1038/s41467-021-25973-x. PMID:34615874[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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