Since guanine is a normal constituent of nucleic acids, the possibility of the direct incorporation of this purine is of great significance in the biosynthesis of nucleic acids. Earlier reports in the literature indicated that preformed guanine was not utilized for nucleic acid production in the rat (1, Z), but more recent evidence suggested that a trace of guanine may be incorporated in the nu...

PreQ1 (2) is a precursor of queuine (1) that in eubacteria incorporated into transfer RNA (tRNA) by tRNA guanine transglycosylase (TGT) before being further elaborated queuine. The modification unusual and occurs across all eukaryotes with few exceptions, but its function remains unclear. As the modified nucleotide through incorporation specially synthesized instead via genetically encoded base...

The glass surface modification with 3-(mercaptopropyl) trimethoxysilane (MPTS), gold nano-particles (GN) and guanine rich single strand DNA (ss-DNA) was utilized as a novel and efficient platform for sensing trace concentration of methylene blue (MB) by an inexpensive spectrophotometric method. Methylene Blue (MB) can interact with the guanine base of single strand DNA and absorbed onto glass s...

In vitro modification of M13 phage single-stranded DMA with 4-hydroxyaminoquinoline 1-oxide (4HAQO) resulted in four kinds of adducts: three guanine adducts, QGh QGn, and QGm;and one adenine adduci, QA, at ratios of 16.4 47.3, 13.7, and 22.6, respectively. The carcinogen-modified DMA, initiated with a se quence-defined oligodeoxynucleotide primer, was replicated in vitro with Escherichia coli D...

There is a small bu t real incorporation of exogenously supplied guanine into the nucleic acid of normal rats (4). The low value of isotope found in the nucleic acids is consistent with the previously published observations with N 15, which indicated no detectable utilization (10, 19), since the amount of incorporation was less than could have been determined with the stable nitrogen isotope. I...

In the title compound, disodium 2-amino-6-oxo-6,7-di-hydro-1H-purine-1,7-diide hepta-hydrate, 2Na(+)·C5H3N5O(2-)·7H2O, the structure is composed of alternating (100) layers of guanine mol-ecules and hydrated Na(+) ions. Within the guanine layer, the mol-ecules are arranged in centrosymmetric pairs, with a partial overlap between the guanine rings. In this compound, guanine exists as the amino-k...

G-quadruplex structures formed by guanine-rich nucleic acids are implicated in essential physiological and pathological processes and nanodevices. G-quadruplexes are normally composed of four Gn (n ≥ 3) tracts assembled into a core of multiple stacked G-quartet layers. By dimethyl sulfate footprinting, circular dichroism spectroscopy, thermal melting, and photo-cross-linking, here we describe a...

Guanine tetraplexes are biological non-covalent systems stabilized by alkali cations. Thus, self-clustering of guanine, xanthine and hypoxanthine with alkali cations (Na(+), K(+) and Li(+)) is investigated by electrospray ionization mass spectrometry (ESI-MS) in order to provide new insights into G-quartets, hydrogen-bonded complexes. ESI assays displayed magic numbers of tetramer adducts with ...

There is a small bu t real incorporation of exogenously supplied guanine into the nucleic acid of normal rats (4). The low value of isotope found in the nucleic acids is consistent with the previously published observations with N 15, which indicated no detectable utilization (10, 19), since the amount of incorporation was less than could have been determined with the stable nitrogen isotope. I...

Ribose 1-phosphate, phosphate, and acyclovir diphosphate quenched the fluorescence of purine nucleoside phosphorylase at pH 7.1 and 25 degrees C. The fluorescence of enzyme-bound guanine was similar to that of anionic guanine in ethanol. Guanine and ribose 1-phosphate bound to free enzyme, whereas inosine and guanosine were not bound to free enzyme in the absence of phosphate. Thus, synthesis p...