The fluorescence of calf thymus DNA is studied by steady-state and time-resolved spectroscopy combining upconversion time-correlated single photon counting. spectrum very similar to that a stoichiometric mixture monomeric chromophores, arising from bright ππ* states, contrasts with the existing picture exciplex emission in natural DNA. Yet, decays span over five decades time, 98% photons being emitted at times longer than 10 ps. These findings, association recent studies on model duplexes,...

The room-temperature fluorescence of 2′-deoxyguanosine 5′-monophosphate (dGMP) in aqueous solution is studied by steady-state and time-resolved spectroscopy. spectrum dGMP shows one band centered at 334 nm but has an extraordinary long red tail, extending beyond 700 nm. Both the quantum yield relative weight peak increase with excitation wavelength. initial anisotropy after 267 lower than 0.2 for all emission wavelengths, indicating ultrafast S2 → S1 internal conversion. decays depend...

Förster resonance energy transfer (FRET) is a technique commonly used to unravel the structure and conformational changes of biomolecules being vital for all living organisms. Typically, FRET performed using dyes attached externally nucleic acids through linker that complicates quantitative interpretation experiments because dye diffusion reorientation. Here, we report versatile, general methodology simulation analysis in acids, demonstrate its particular power modelling between probes...

The DNA double helix poly(dGdC).poly(dGdC) is studied by fluorescence upconversion spectroscopy with femtosecond resolution. It shown that the excited-state relaxation of duplex faster than monomeric components dGMP and dCMP. This contrasts behavior duplexes composed exclusively adenine-thymine base pairs, for which an overall lengthening lifetimes respect to equimolar mixture dAMP TMP was reported previously. Despite difference in deactivation rate between two types duplexes, signature...

DNA nanostructures formed by association of four oligonucleotides d(TGGGGT) (TG4T quadruplexes) are studied steady-state and time-resolved optical spectroscopy with femtosecond resolution using fluorescence upconversion. A comparison between single-stranded four-stranded structures the corresponding stoichiometric mixture noninteracting nucleotides shows how horizontal vertical organization affects properties excited states. Emission from guanine excimers is observed only for single strands,...

Dark DNA light: "Dark" excited states of alternating GC double strands emit fluorescence at 4000 cm−1 higher energy (see spectrum) and with four orders magnitude longer lifetime compared to the bright ππ* states. Such high-energy long-lived are expected play a key role in photoreactivity associated appearance carcinogenic mutations.

Abstract Fluorescent‐base analogues (FBAs) comprise a group of increasingly important molecules for the investigation nucleic acid structure and dynamics as well interactions between acids other molecules. Here, we report on synthesis, detailed spectroscopic characterisation base‐pairing properties new environment‐sensitive fluorescent adenine analogue, quadracyclic (qA). After developing an efficient route synthesis phosphoramidite qA it was incorporated into DNA in high yield by using...

While the physicochemical properties as well NMR and vibration spectroscopic data of mixtures ionic liquids (ILs) with molecular solvents undergo a drastic change around IL mole fraction 0.2, local structure pertaining to this behavior remains unclear. In work, 12 1-butyl-3-methylimidazolium cation (C4mim+) combined perfluorinated anions, such tetrafluoroborate (BF4-), hexafluorophosphate (PF6-), trifluoromethylsulfonate (TFO-), bis(trifluoromethanesulfonyl)imide, (TFSI-), aprotic dipolar...

A C–C bond forming reaction occurs spontaneously between tris-(2,6-dimethoxyphenyl)carbenium ions and indoles/anilines. The carbocation acts both as an electrophile oxidant. Effective cationic π-conjugated dyes are formed resulting in a strong hyper- bathochromism.

The most abundant of the modified nucleosides, and once considered as "fifth" nucleotide in RNA, is pseudouridine, which results from action pseudouridine synthases. Recently, mammalian synthase 1 (hPus1p) has been reported to modulate class I II nuclear receptor responses through its ability modify Steroid RNA Activator (SRA). These findings highlight a new level regulation (NR)-mediated transcriptional responses. We have characterised association activity human Pus1p enzyme with unusual...

Novel fluorescent triazole adenine derivatives have been synthesised and their photo-physical properties characterised.

In order to determine the self-diffusion coefficients D of all species in solutions at 298.2 K, 1H and 19F NMR diffusion ordered spectroscopy (DOSY) has been conducted on coumarin 153 (C153) binary mixed solvents an imidazolium-based ionic liquid (IL), 1-dodecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide (C12mimTFSA), with three molecular liquids (MLs) chloroform (CL), benzene (BZ), propylene carbonate (PC) as a function ML mole fraction xML. Below xML ≈ 0.8, values each do not...

The changes of the local structure in binary mixture 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF6) ionic liquid and acetonitrile are investigated over entire composition range. Two charge distribution models ions considered: first one, atomic fractional charges cations anions kept equal with those neat liquid, hence they independent from mole fraction while second one is scaled up by a dependent factor. sum these converge to +1e -1e on cation anion, respectively, at infinite...

We conducted a study on the photophysics of three indoline dyes, D102, D149, and D205, in binary mixtures ionic liquids (IL) polar aprotic molecular solvents (MS). Specifically, we examined behavior these dyes IL-MS containing four different imidazolium-based ILs MSs. Our investigation involved several techniques, including stationary absorption emission measurements, as well femtosecond transient (TA) spectroscopy. Through our analysis, discovered peculiar photophysical properties at low IL...

Background and aims Multidrug resistance (MDR) limits effectiveness in treating malignancy by modifying internalisation and/or externalisation of drugs through cancer cell membranes. In this study we describe an assay to monitor patients’ responses chemotherapy. Methods The is based on the fluorescent properties doxorubicin alone as well combination with methotrexate, vinblastine, cisplatin (MVAC). slide-based imaging technique was first optimised using a panel breast urothelial lines then...

Hydrogen bond interactions significantly affect the coumarin-153's (C153) photophysics, including its ability to act as a donor of weak hydrogen bonds via 14 C–H and an acceptor O atoms in ester carbonyl groups, well F atom trifluoromethyl group. The distances between their closest electronegative neighbor served descriptors interactions. These were calculated using nearest radial distribution approach. Principal component analysis (PCA) was then performed on these compare unique structures...

Abstract In this work, we investigated for the first time morin in MeOH at different pH values by picosecond time‐resolved fluorescence. We identified two species responsible fluorescence low and high pH. The solvated morin‐solvent hydrogen‐bonded complex has been experimentally observed time. give also typical spectra as well lifetimes of probable emitting species. work put forward new insights concerning contribution free to hope that these data improve accuracy interpretation cation:morin...