Selected deprotonated oligodeoxynucleotides generated by electrospray ionization were exposed to a variety of neutral molecules in the gas phase at room temperature in flowing helium gas at 0.35 Torr. Single-stranded [AGTCTG-nH]n- and single- and double-stranded [GCATGC-nH]n- anions were found to be remarkably unreactive with strong oxidants (O3, O2, N2O) and potential intercalators (benzene, pyridine, toluene, and quinoxaline). Hydration also was observed to be inefficient. However, [AGTCTG-nH]n- anions with n=2, 3, 4, and 5 were seen to be sequentially protonated and/or hydrobrominated with HBr (but not damaged) and displayed an interesting "end effect" against protonation. Measurements are provided for the rate coefficients of reaction and the efficiencies of protonation. These experimental results point toward the exciting prospect of measuring the intrinsic chemistry of other bare DNA-like anions, including double-stranded oligonucleotide anions in the gas phase at room temperature.
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http://dx.doi.org/10.1021/jp804193u | DOI Listing |
Chem Commun (Camb)
January 2025
Chemistry Division, Brookhaven National Laboratory, Upton, NY 11973-5000, USA.
This review discusses the properties of strongly oxidizing radicals in organic and aqueous media and highlights the challenges in obtaining accurate values of their reduction potentials. Transient redox equilibrium methods based on the use of strong photooxidants or initiated by pulse radiolysis are shown to provide versatile approaches for decoupling electron transfer reactions from follow-up reactivity of unstable radical species, resulting in accurate values of reduction potentials of very positive couples, including some solvent radical cations. We also show that correlations of reduction potentials with Hammett ∑+p parameters, as well as gas phase ionization potentials, can be used to estimate the redox properties of unknown couples within a homologous series of compounds.
View Article and Find Full Text PDFACS Nano
January 2025
Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.
Bismuth oxyselenide (BiOSe) stands as a highly promising layered semiconductor with outstanding optical, electrical, and thermal properties. For the practical application of the material toward the devices, growing BiOSe directly on the amorphous substrate at low temperatures (<400 °C) is essential; however, the negatively charged bottom Se layer originating from alternating stacks of Se and [BiO] has hindered this process. In this work, we report the method for synthesizing a BiOSe film on amorphous alumina (AlO) directly at 350 °C by using chemical solution deposition.
View Article and Find Full Text PDFAppl Microbiol Biotechnol
January 2025
Marine Biological Section, Department of Biology, University of Copenhagen, Helsingør, Denmark.
One strategy for CO mitigation is using photosynthetic microorganisms to sequester CO under high concentrations, such as in flue gases. While elevated CO levels generally promote growth, excessively high levels inhibit growth through uncertain mechanisms. This study investigated the physiology of the cyanobacterium Synechocystis sp.
View Article and Find Full Text PDFAnal Chem
January 2025
Shanghai University of Sport, 399 Changhai Road, Shanghai 200438, China.
Oxymetholone and methasterone are anabolic androgenic steroids prohibited by the World Anti-Doping Agency (WADA) for both in-competition and out-of-competition use. Detecting metabolites of exogenous steroids is crucial for establishing doping violations, making the study of these metabolites essential in antidoping efforts. This study investigated the urinary metabolic profiles of oxymetholone and methasterone using gas chromatography-orbitrap high-resolution mass spectrometry (GC-Orbitrap-HRMS) in nanogram level by utilizing a novel multiplex nontargeted framework protocol.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Departamento de Físico-Química, Instituto de Química - Universidade Federal da Bahia, Rua Barão de Jeremoabo, 147, Salvador, Bahia, 40170-115, Brazil.
We report a computational study of the gas-phase and water-mediated mechanisms for the oxidation of carbonyl sulfide (OCS) by the hydroxyl radical. To achieve reliable results, we employ a dual-level strategy within interpolated single-point energies (VTST-ISPE) at the CCSD(T)/aug-cc-pVTZ//M06-2X/aug-cc-pVTZ level of theory. In the gas-phase mechanism, we have determined the rate constants by kinetic Monte Carlo simulation in the interval of temperatures of 250-550 K.
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