Crystal structures of A-form and B-form DNA duplexes containing 2'-S-methyl-uridines reveal that the modified residues adopt a RNA-like C3'-endo pucker, illustrating that the replacement of electronegative oxygen at the 2'-carbon of RNA by sulfur does not appear to fundamentally alter the conformational preference of the sugar in the oligonucleotide context and sterics trump stereoelectronics.
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http://dx.doi.org/10.1039/b822781k | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Department of Ecology and Evolution, University of Chicago, Chicago, IL 60637.
Many proteins form paralogous multimers-molecular complexes in which evolutionarily related proteins are arranged into specific quaternary structures. Little is known about the mechanisms by which they acquired their stoichiometry (the number of total subunits in the complex) and heterospecificity (the preference of subunits for their paralogs rather than other copies of the same protein). Here, we use ancestral protein reconstruction and biochemical experiments to study historical increases in stoichiometry and specificity during the evolution of vertebrate hemoglobin (Hb), an αβ heterotetramer that evolved from a homodimeric ancestor after a gene duplication.
View Article and Find Full Text PDFActa Crystallogr F Struct Biol Commun
February 2025
Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York, USA.
Periodontal diseases afflict 20-50% of the global population and carry serious health and economic burdens. Chronic periodontitis is characterized by inflammation of the periodontal pocket caused by dysbiosis. This dysbiosis is coupled with an increase in the population of Treponema denticola, a spirochete bacterium with high mobility and invasivity mediated by a number of virulence factors.
View Article and Find Full Text PDFNat Commun
January 2025
NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
Membrane bound histidine kinases (HKs) are ubiquitous sensors of extracellular stimuli in bacteria. However, a uniform structural model is still missing for their transmembrane signaling mechanism. Here, we used solid-state NMR in conjunction with crystallography, solution NMR and distance measurements to investigate the transmembrane signaling mechanism of a paradigmatic citrate sensing membrane embedded HK, CitA.
View Article and Find Full Text PDFAnal Chem
January 2025
Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology (TUAT), 2-24-16 Naka-cho Koganei-shi, Tokyo 184-8588, Japan.
Nanopore sensing is widely used for single-molecule detection, originally applied to nucleic acids and now extended to protein sensing. Our study focuses on the complex conformational changes of peptides in nanopores, which may have implications for peptide fingerprinting and protein identification. Specifically, we investigated the interaction of a β-hairpin peptide (SV28) within an α-hemolysin (αHL) nanopore.
View Article and Find Full Text PDFSci Adv
January 2025
The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Controlling the reactivity of bonds along polymer chains enables both functionalization and deconstruction with relevance to chemical recycling and circularity. Because the substrate is a macromolecule, however, understanding the effects of chain conformation on the reactivity of polymer bonds emerges as important yet underexplored. Here, we show how oxy-functionalization of chemically recyclable condensation polymers affects acidolysis to monomers through control over distortion and interaction energies in the rate-limiting transition states.
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