Near-quantitative DNA bioconjugation and detailed mechanistic investigations of reactions involving 5-(vinyl)-2'-deoxyuridine (VdU) and maleimides are reported. According to accelerated reaction rates in solvents with increasing polarity and trends in product stereochemistry, VdU-maleimide reactions proceed via a formal [4 + 2] stepwise cycloaddition. In contrast, 5-(1,3-butadienyl)-2'-deoxyuridine (BDdU) reacts with maleimides in a concerted [4 + 2] Diels-Alder cycloaddition. VdU-maleimide reactions enable high-yielding bioconjugation of duplex DNA in vitro (>90%) as well as metabolic labeling experiments in cells.
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http://dx.doi.org/10.1021/acs.bioconjchem.3c00090 | DOI Listing |
In duplex DNA, A-T and G-C form Watson-Crick base pairs, and Hoogsteen pairing only dominates upon protein binding or DNA damage. Using NMR, we show that an A-T Hoogsteen base pair previously observed in crystal structures of transposon DNA hairpins bound to TnpA protein forms in solution even in the absence of TnpA. This Hoogsteen base pair, located adjacent to a dinucleotide apical loop, exists in dynamic equilibrium with a minor Watson-Crick conformation (population ∼11% and lifetime ∼55 µs).
View Article and Find Full Text PDFInt J Parasitol Parasites Wildl
April 2025
Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada.
The caribou ( sspp.) is a keystone wildlife species in northern ecosystems that plays a central role in the culture, spirituality and food security of Indigenous People. The Arctic is currently experiencing an unprecedented rate of climate change, including warming temperatures and altered patterns of precipitation.
View Article and Find Full Text PDFFront Bioinform
December 2024
Bioengineering Unit, Life Sciences Department, Walloon Agricultural Research Centre, Gembloux, Belgium.
Background: The study of sample taxonomic composition has evolved from direct observations and labor-intensive morphological studies to different DNA sequencing methodologies. Most of these studies leverage the metabarcoding approach, which involves the amplification of a small taxonomically-informative portion of the genome and its subsequent high-throughput sequencing. Recent advances in sequencing technology brought by Oxford Nanopore Technologies have revolutionized the field, enabling portability, affordable cost and long-read sequencing, therefore leading to a significant increase in taxonomic resolution.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Department of Physical Chemistry, Faculty of Science, Palacky University, 17. listopadu 12, Olomouc 77146, Czech Republic.
The transition from B-DNA to A-DNA occurs in many protein-DNA interactions or in DNA/RNA hybrid duplexes, and thus plays a role in many important biomolecular processes that convey the biological function of DNA. However, the stability of A-DNA is severely underestimated in current AMBER force fields such as OL15, OL21 or bsc1, potentially leading to unstable or deformed protein-DNA complexes. In this study, we refine the deoxyribose dihedral potential to increase the stability of the north (N) puckering present in A-DNA.
View Article and Find Full Text PDFNat Commun
January 2025
Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China.
Monovalent salts are generally believed to stabilize DNA duplex by weakening inter-strand electrostatic repulsion. Unexpectedly, our force-induced hairpin unzipping experiments and thermal melting experiments show that LiCl, NaCl, KCl, RbCl, and CsCl at concentrations beyond ~1 M destabilize DNA, RNA, and RNA-DNA duplexes. The two types of experiments yield different changes in free energy during melting, while the results that high concentration monovalent salts destabilize duplexes are common.
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