The structural basis of minor groove recognition of a DNA duplex containing synthetic genetic information by hairpin pyrrole-imidazole polyamides is described. Hairpin polyamides induce a higher melting stabilization of a DNA duplex containing the unnatural P·Z base-pair when an imidazole unit is aligned with a P nucleotide. An NMR structural study showed that the incorporation of two isolated P·Z pairs enlarges the minor groove and slightly narrows the major groove at the site of this synthetic genetic information, relative to a DNA duplex consisting entirely of Watson-Crick base-pairs. Pyrrole-imidazole polyamides bind to a P·Z-containing DNA duplex to form a stable complex, effectively mimicking a G·C pair. A structural hallmark of minor groove recognition of a P·Z pair by a polyamide is the reduced level of allosteric distortion induced by binding of a polyamide to a DNA duplex. Understanding the molecular determinants that influence minor groove recognition of DNA containing synthetic genetic components provides the basis to further develop unnatural base-pairs for synthetic biology applications.
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Biophys J
January 2025
Department of Physics, Northeastern University, Boston, MA, 02115, USA. Electronic address:
Binuclear ruthenium complexes have been investigated for potential DNA-targeted therapeutic and diagnostic applications. Studies of DNA threading intercalation, in which DNA base pairs must be broken for intercalation, have revealed means of optimizing a model binuclear ruthenium complex to obtain reversible DNA-ligand assemblies with the desired properties of high affinity and slow kinetics. Here, we used single-molecule force spectroscopy to study a binuclear ruthenium complex with a longer semi-rigid linker relative to the model complex.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Department of Physics, Novosibirsk State University, 2 Pirogov Str., Novosibirsk 630090, Russia.
Nowadays, nucleic acid derivatives capable of modulating gene expression at the RNA level have gained widespread recognition as promising therapeutic agents. A suitable degree of biological stability of oligonucleotide therapeutics is required for in vivo application; this can be most expeditiously achieved by the chemical modification of the internucleotidic phosphate group, which may also affect their cellular uptake, tissue distribution and pharmacokinetics. Our group has previously developed a strategy for the chemical modification of the phosphate group via the Staudinger reaction on a solid phase of the intermediate dinucleoside phosphite triester and a range of, preferably, electron deficient organic azides such as sulfonyl azides during automated solid-phase DNA synthesis according to the conventional β-cyanoethyl phosphoramidite scheme.
View Article and Find Full Text PDFMolecules
December 2024
Department of Biology, Lomonosov Moscow State University, Leninskie Gory 1-12, 119234 Moscow, Russia.
Sulfonated indocyanines 3 and 5 (sCy3, sCy5) are widely used to label biomolecules. Their high molar absorption coefficients and lack of spectral overlap with biopolymers make them ideal as linker components for rapid assessment of bioconjugate stoichiometry. We recently found that the determination of the sCy3:sCy5 molar ratio in a conjugate from its optical absorption spectrum is not straightforward, as the sCy3:sCy5 absorbance ratio at the maxima tends to be larger than expected.
View Article and Find Full Text PDFBiochem Biophys Rep
March 2025
Department of Chemistry and Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL, 33431, USA.
Nile blue has been widely used in histological staining, fluorescence labeling, and DNA probing, with its intercalation behavior into the DNA helix being well documented. Here, we present a comprehensive investigation to address a current knowledge gap regarding the binding properties of Nile blue to two types of double-stranded RNA (dsRNA): poly(A·U) and poly(I·C), using various biophysical techniques. Absorption and fluorescence spectroscopic studies suggest a significant binding interaction between Nile blue and the two designated dsRNAs, specifically indicating an intercalation binding mode with poly(A·U) and demonstrating a noticeably higher binding affinity compared to poly(I·C).
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Oxidative Stress Group, Department of Molecular Biosciences, University of South Florida, 4202 E. Fowler Avenue, Tampa, FL 33620, USA.
Most of the risk factors associated with chronic and complex diseases, such as cancer, stem from exogenous and endogenous exposures experienced throughout an individual's life, collectively known as the exposome. These exposures can modify DNA, which can subsequently lead to the somatic mutations found in all normal and tumor tissues. Understanding the precise origins of specific somatic mutations has been challenging due to multitude of DNA adducts (i.
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