Our structures thus provide insights into the molecular virology of the influenza virus.Non-coding RNAs are regarded as promising targets for the discovery of innovative drugs due to their abundance in the genome and their involvement in many biological processes. Phytochemicals (PCs) are the primary source of ligand-based drugs due to their broad spectrum of biological activities. Since many PCs are heterocyclic and have chemical groups potentially involved in the interaction with nucleic acids, detailed interaction analysis between PCs and RNA is crucial to explore the effect of PCs on RNA functions. In this study, an integrated approach for investigating interactions between PCs and RNAs were demonstrated to verify the RNA-mediated PCs functions by using berberine (BRB) as a model PC. RNA screening of a transcriptome library followed by sequence refinement found minimal RNA motif consisting of a cytosine bulge with U-A and G-U neighbouring base pairs for interaction with BRB. NMR-based structure determination and physicochemical analyses using chemical analogues of BRB demonstrated the importance of electrostatic and stacking interactions for sequence selective interaction and RNA stabilization. The selective interaction with a relatively small RNA motif based on a chemical structure of a planer heterocyclic highlights the biological activities of various PCs mediated by the interactions with particular functional RNAs. In addition, the systematic and quantitative investigations demonstrated in this study could be useful for the development of therapeutic chemicals targeting functional RNAs, based on the PCs, in the future.Mutations within the mtrR gene are commonly found amongst multidrug resistant clinical isolates of Neisseria gonorrhoeae, which has been labelled a superbug by the Centers for Disease Control and Prevention. These mutations appear to contribute to antibiotic resistance by interfering with the ability of MtrR to bind to and repress expression of its target genes, which include the mtrCDE multidrug efflux transporter genes and the rpoH oxidative stress response sigma factor gene. However, the DNA-recognition mechanism of MtrR and the consensus sequence within these operators to which MtrR binds has remained unknown. In this work, we report the crystal structures of MtrR bound to the mtrCDE and rpoH operators, which reveal a conserved, but degenerate, DNA consensus binding site 5′-MCRTRCRN4YGYAYGK-3′. We complement our structural data with a comprehensive mutational analysis of key MtrR-DNA contacts to reveal their importance for MtrR-DNA binding both in vitro and in vivo. Furthermore, we model and generate common clinical mutations of MtrR to provide plausible biochemical explanations for the contribution of these mutations to multidrug resistance in N. gonorrhoeae. Collectively, our findings unveil key biological mechanisms underlying the global stress responses of N. gonorrhoeae.The taxonomic analysis of sequencing data has become important in many areas of life sciences. However, currently available tools for that purpose either consume large amounts of RAM or yield insufficient quality and robustness. Here, we present kASA, a k-mer based tool capable of identifying and profiling metagenomic DNA or protein sequences with high computational efficiency and a user-definable memory footprint. We ensure both high sensitivity and precision by using an amino acid-like encoding of k-mers together with a range of multiple k’s. Custom algorithms and data structures optimized for external memory storage enable a full-scale taxonomic analysis without compromise on laptop, desktop, and HPCC.The ability to dynamically remodel DNA origami structures or functional nanodevices is highly desired in the field of DNA nanotechnology. Concomitantly, the use of fluorophores to track and validate the dynamics of such DNA-based architectures is commonplace and often unavoidable. It is therefore crucial to be aware of the side effects of popular fluorophores, which are often exchanged without considering the potential impact on the system. Here, we show that the choice of fluorophore can strongly affect the reconfiguration of DNA nanostructures. To this end, we encapsulate a triple-stranded DNA (tsDNA) into water-in-oil compartments and functionalize their periphery with a single-stranded DNA handle (ssDNA). Thus, the tsDNA can bind and unbind from the periphery by reversible opening of the triplex and subsequent strand displacement. Using a combination of experiments, molecular dynamics (MD) simulations, and reaction-diffusion modelling, we demonstrate for 12 different fluorophore combinations that it is possible to alter or even inhibit the DNA nanostructure formation-without changing the DNA sequence. Besides its immediate importance for the design of pH-responsive switches and fluorophore labelling, our work presents a strategy to precisely tune the energy landscape of dynamic DNA nanodevices.Eukaryotic rRNAs and snRNAs are decorated with abundant 2′-O-methylated nucleotides (Nm) that are predominantly synthesized by box C/D snoRNA-guided enzymes. In the model plant Arabidopsis thaliana, C/D snoRNAs have been well categorized, but there is a lack of systematic mapping of Nm. Here, we applied RiboMeth-seq to profile Nm in cytoplasmic, chloroplast and mitochondrial rRNAs and snRNAs. N-butyl-N-(4-hydroxybutyl) nitrosamine purchase We identified 111 Nm in cytoplasmic rRNAs and 19 Nm in snRNAs and assigned guide for majority of the detected sites using an updated snoRNA list. At least four sites are directed by guides with multiple specificities as shown in yeast. We found that C/D snoRNAs frequently form extra pairs with nearby sequences of methylation sites, potentially facilitating the substrate binding. Chloroplast and mitochondrial rRNAs contain five almost identical methylation sites, including two novel sites mediating ribosomal subunit joining. Deletion of FIB1 or FIB2 gene reduced the accumulation of C/D snoRNA and rRNA methylation with FIB1 playing a bigger role in methylation. Our data reveal the comprehensive 2′-O-methylation maps for Arabidopsis rRNAs and snRNAs and would facilitate study of their function and biosynthesis.