A new approach to the investigation of the proton-disordered structure of clathrate hydrates is presented. This approach is based on topological crystallography. The quotient graphs were built for the unit cells of the cubic structure I and the hexagonal structure H. This is a very convenient way to represent the topology of a hydrogen-bonding network under periodic boundary conditions. The exact proton configuration statistics for the unit cells of structure I and structure H were obtained using the quotient graphs. In addition, the statistical analysis of the proton transfer along hydrogen-bonded chains was carried out.
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http://dx.doi.org/10.1107/S2053273315008864 | DOI Listing |
Biochem Biophys Res Commun
January 2025
Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China; Department of Pharmacology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, 300070, China. Electronic address:
Bacterial adaptive immunity, driven by CRISPR-Cas systems, protects against foreign nucleic acids from mobile genetic elements (MGEs), like bacteriophages. The type I-E CRISPR-Cas system employs the Cascade (CRISPR-associated complex for antiviral defense) complex for target DNA cleavage, guided by crRNA. Anti-CRISPR (Acr) proteins, such as AcrIE7, counteract this defense by inhibiting Cascade activity.
View Article and Find Full Text PDFNature
December 2024
Protein-Nucleic Acid Interaction Section, Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD, USA.
Much of the human genome is transcribed into RNAs, many of which contain structural elements that are important for their function. Such RNA molecules-including those that are structured and well-folded-are conformationally heterogeneous and flexible, which is a prerequisite for function, but this limits the applicability of methods such as NMR, crystallography and cryo-electron microscopy for structure elucidation. Moreover, owing to the lack of a large RNA structure database, and no clear correlation between sequence and structure, approaches such as AlphaFold for protein structure prediction do not apply to RNA.
View Article and Find Full Text PDFActa Crystallogr A Found Adv
January 2025
Department of Crystallography, Faculty of Chemistry, Adam Mickiewicz University, Poznań, Poland.
J Am Chem Soc
January 2025
School of Physical Science and Technology & Shanghai Key Laboratory of High-Resolution Electron Microscopy, ShanghaiTech University, Shanghai 201210, China.
The structural characterization of new materials often poses immense challenges, especially when obtaining single-crystal structures is difficult, which is a common difficulty with covalent organic frameworks (COFs). Despite this, understanding the atomic structure is crucial as it provides insights into the arrangement and connectivity of organic building blocks, offering the opportunity to establish the correlation of structure-function relationships and unravel material properties. In this study, we present an approach for determining the structures of COFs, an integration of electron crystallography and computational intelligence (COF+).
View Article and Find Full Text PDFNano Lett
November 2024
Department of Chemistry, New York University, New York, New York 10003, United States.
Artificially expanded genetic information systems (AEGIS) were developed to expand the diversity and functionality of biological systems. Recent experiments have shown that these expanded DNA molecular systems are robust platforms for information storage and retrieval as well as useful for basic biotechnologies. In tandem, nucleic acid nanotechnology has seen the use of information-based "semantomorphic" encoding to drive the self-assembly of a vast array of supramolecular devices.
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