Crown ethers (CEs), macrocyclic polyethers, have attracted significant attention in supramolecular chemistry. It is known that they have many isomers due to their flexibility. It is challenging to select some exact conformation and tune the following self-assembly structure of CEs, and it has rarely been reported to date. Herein, by choosing 18-crown-6-ether and dibenzo-18-crown-6-ether for study, we report an effective stereoisomeric selectivity of CEs by a strategy of both chemical modification and CEs hosting Na/K ions. The conformational difference in CEs can further tune the molecular interactions, resulting in the chiral self-assembly structures of CEs. By the combination of scanning tunneling microscopy, density functional theory, and X-ray photoelectron spectroscopy, this study reveals the underlying mechanism of CEs in both conformational selectivity and the formation of chiral assembly structures.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1021/acsnano.4c15062 | DOI Listing |
J Am Soc Mass Spectrom
January 2025
Department of Chemistry, Washington State University, Pullman, Washington 99164, United States.
Phased structures for lossless ion manipulation offer significant improvements over the scanning second gate method for coupling with ion trap mass analyzers. With an experimental run time of under 1 min for select conditions and an average run time of less than 4 min, this approach significantly reduces experimental time while enhancing the temporal duty cycle. The outlined SLIM system connects to an ion trap mass analyzer via a PCB stacked ring ion guide, which replaces the commercial ion optics and capillary inlet.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU, U.K.
Mechanisms of anion permeation within ion channels and nanopores remain poorly understood. Recent cryo-electron microscopy structures of the human bestrophin 1 Cl channel (hBest1) provide an opportunity to evaluate ion interactions predicted by molecular dynamics (MD) simulations against experimental observations. Here, we implement the fully polarizable force field AMOEBA in MD simulations on different conformations of hBest1.
View Article and Find Full Text PDFMol Genet Genomics
January 2025
Department of Botany, Biology Institute, UnB, Brasília, DF, 70910-900, Brazil.
Precursors of microRNAs (pre-miRNAs) are less used in silico to mine miRNAs. This study developed PmiR-Select based on covariance models (CMs) to identify new pre-miRNAs, detecting conserved secondary structural features across RNA sequences and eliminating the redundancy. The pipeline preceded PmiR-Select filtered 20% plant pre-miRNAs (from 38589 to 8677) from miRBase.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Colorado State University, Fort Collins, CO, USA.
Background: In tauopathies, the protein tau misfolds into a b-sheet conformation that self-templates and spreads throughout the brain causing progressive degeneration. Biological and structural data have shown that the shape, or strain, that tau adopts when it misfolds determines which disease a patient will develop. We previously used HEK293T cells expressing TauRD-YFP to show that tau strain formation is isoform-specific.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
TauC3 Biologics Limited, London, United Kingdom.
Background: Tau abnormalities are a central feature of Alzheimer's disease (AD) and the defining feature of non-AD tauopathies, which include frontotemporal lobar degeneration (FTLD) due to Pick's disease (PiD) or Mapt mutations (FTLD-tau), as well as progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and others. Mapt transcripts undergo alternative splicing to produce 6 distinct isoforms. Exon 2 splicing produces 0, 1 or 2 inserts; exclusion or inclusion of exon 10 results in 3-repeat (3R) or 4-repeat (4R) forms, respectively.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!