Uracil arises in DNA from spontaneous deamination of cytosine and through incorporation of dUMP by DNA polymerase during DNA replication. Excision of uracil by the action of uracil-DNA glycosylase (Ung) initiates the base excision repair pathway to counter the promutagenic base modification. In this study, we cloned a cDNA-encoding Caenorhabditis elegans homologue (CeUng-1) of Escherichia coli ...

The transport of uracil into the yeast Saccharomyces cerevisiae is mediated by uracil permease, a specific co-transporter encoded by the FUR4 gene. Uracil permease is a multispan membrane protein that is delivered to the plasma membrane via the secretory pathway. Experimental results led to the proposal of a two-dimensional model of the protein's topology. According to this model, the membrane ...

The DNA base excision repair pathway is responsible for removal of oxidative and endogenous DNA base damage in both prokaryotes and eukaryotes. This pathway involves formation of an apurinic/apyrimidinic (AP) site in the DNA, which is further processed to restore the integrity of the DNA. In Escherichia coli it has been suggested that the major mode of repair involves replacement of a single nu...

The hydrogen-bonded complexes of 17a-ethinyl-estradiol, progesterone, and testosterone with adenineand uracil-derivatives have been investigated by means of nuclear magnetic resonance (NMR) spectroscopy using deutero-chloroform as a solvent. The thermodynamic and NMR-parameters (equilibrium constant K, enthalpy AH, entropy AS, and relative chemical shift of the com­ plexes A8C) for selfassociat...

Thymine is reduced in dimethyl sulfoxide (E 1/2 of -2.4 V); the decrease in apparent faradaic IZ from one at infinite dilution to two-thirds at concentrations above 2 m&Z is due to proton transfer by thymine to the initially formed radical anion and the anion formed on reduction of the resulting free radical, which is more easily reduced than the parent compound. The proton transfer, which is m...

Archaeal family-D DNA polymerase is inhibited by the presence of uracil in DNA template strands. When the enzyme encounters uracil, following three parameters change: DNA binding increases roughly 2-fold, the rate of polymerization slows by a factor of ≈ 5 and 3'-5' proof-reading exonuclease activity is stimulated by a factor of ≈ 2. Together these changes result in a significant decrease in po...

Base-excision repair and control of nucleotide pools safe-guard against permanent uracil accumulation in DNA relying on two key enzymes: uracil-DNA glycosylase and dUTPase. Lack of the major uracil-DNA glycosylase UNG gene from the fruit fly genome and dUTPase from fruit fly larvae prompted the hypotheses that i) uracil may accumulate in Drosophila genomic DNA where it may be well tolerated, an...

Nocardia cultures, isolated from soil by use of n-paraffins as the sole carbon source, have been shown to bring about significant oxidation of several methyl-substituted mono- and dicyclic aromatic hydrocarbons. Oxygen uptake by washed cell suspensions was not a reliable indicator of oxidation. Under co-oxidation conditions in shaken flasks, o- and p-xylenes were oxidized to their respective mo...