Nucleotide-specific RNA conformations and dynamics within ribonucleoprotein condensates.

Ribonucleoprotein (RNP) condensates have distinct physiological and pathological significance, but the structure of RNA within them is not well understood. Using contrast-variation solution X-ray scattering, which discerns only the RNA structures within protein-RNA complexes, alongside ensemble-based structural modeling we characterize the conformational changes of flexible poly-A, poly-U and poly-C single stranded RNA as it interacts with polybasic peptides, eventually forming condensed coacervate mixtures. At high salt concentrations, where macromolecular association is weak, we probe association events that precede the formation of liquid-like droplets.

RNA structures and dynamics with Å resolution revealed by x-ray free-electron lasers.

RNA macromolecules, like proteins, fold to assume shapes that are intimately connected to their broadly recognized biological functions; however, because of their high charge and dynamic nature, RNA structures are far more challenging to determine. We introduce an approach that exploits the high brilliance of x-ray free-electron laser sources to reveal the formation and ready identification of angstrom-scale features in structured and unstructured RNAs. Previously unrecognized structural signatures of RNA secondary and tertiary structures are identified through wide-angle solution scattering experiments.

Selective C(sp)-S Bond Cleavage of Thioethers to Build Up Unsymmetrical Disulfides.

The selective C(sp)-S bond cleavage of thioethers was first developed to prepare unsymmetrical disulfides by using electrophilic halogenation reagents. In this strategy, NBS (-bromosuccinimide) achieves selective furfuryl C(sp)-S bond cleavage of furfuryl alkylthioethers at room temperature. Meanwhile, NFSI (-fluorobenzenesulfonimide) enables selective methyl C(sp)-S bond cleavage of aryl and alkyl methylthioethers at an elevated temperature.

RNA structures and dynamics with Å resolution revealed by x-ray free electron lasers.

RNA macromolecules, like proteins, fold to assume shapes that are intimately connected to their broadly recognized biological functions; however, because of their high charge and dynamic nature, RNA structures are far more challenging to determine. We introduce an approach that exploits the high brilliance of x-ray free electron laser sources to reveal the formation and ready identification of Å scale features in structured and unstructured RNAs. New structural signatures of RNA secondary and tertiary structures are identified through wide angle solution scattering experiments.

The effect of a spontaneous induction prophage, phi458, on biofilm formation and virulence in avian pathogenic .

Prophage sequences are present in most bacterial genomes and account for up to 20% of its host genome. Integration of temperate phages may have an impact on the expression of host genes, while some prophages could turn into the lytic cycle and affect bacterial host biological characteristics. We investigated the role of spontaneous induction prophages in avian pathogenic (APEC), which is the causative agent of avian colibacillosis in poultry, and considered a potential zoonotic bacterium related to the fact it serves as an armory of extraintestinal pathogenic .

Ligand-promoted palladium-catalyzed β-methylene C-H arylation of primary aldehydes.

The transient directing group (TDG) strategy allowed long awaited access to the direct β-C(sp)-H functionalization of unmasked aliphatic aldehydes palladium catalysis. However, the current techniques are restricted to terminal methyl functionalization, limiting their structural scopes and applicability. Herein, we report the development of a direct Pd-catalyzed methylene β-C-H arylation of linear unmasked aldehydes by using 3-amino-3-methylbutanoic acid as a TDG and 2-pyridone as an external ligand.