Structure and function of preQ1 riboswitches

Authors

Catherine D. Eichhorn, University of California, Los AngelesFollow
Mijeong Kang, University of California, Los Angeles
Juli Feigon, University of California, Los AngelesFollow

Date of this Version

2014

Citation

Biochim Biophys Acta 1839(10): 939–950

Comments

© 2014 Elsevier B.V.

NIH Public Access

doi:10.1016/j.bbagrm.2014.04.019

Abstract

PreQ₁ riboswitches help regulate the biosynthesis and transport of PreQ₁ (7-aminomethyl-7- deazaguanine), a precursor of the hypermodified guanine nucleotide queuosine (Q), in a number of Firmicutes, Proteobacteria, and Fusobacteria. Queuosine is almost universally found at the wobble position of the anticodon in asparaginyl, tyrosyl, histidyl and aspartyl tRNAs, where it contributes to translational fidelity. Two classes of PreQ₁ riboswitches have been identified (PreQ₁-I and PreQ₁-II), and structures of examples from both classes have been determined. Both classes form H-type pseudoknots upon PreQ₁ binding, each of which has distinct unusual features and modes of PreQ₁ recognition. These features include an unusually long loop 2 in PreQ₁-I pseudoknots and an embedded hairpin in loop 3 in PreQ₁-II pseudoknots. PreQ₁-I riboswitches are also notable for their unusually small aptamer domain, which has been extensively investigated by NMR, X-ray crystallography, FRET, and other biophysical methods. Here we review the discovery, structural biology, ligand specificity, cation interactions, folding, and dynamics, and applications to biotechnology of PreQ₁ riboswitches.