Recent multi-photon ionization (MPI) experiments on uracil revealed a fragment ion at m/z 84 that was proposed as a potential marker for ring opening in the electronically excited neutral molecule. The present MPI measurements on deuterated uracil identify the fragment as C3H4N2O (uracil less CO), a plausible dissociative ionization product from the theoretically predicted open-ring isomer. Equ...

In Experiment 1, groups of thirty 6-wk-old male and female F344 rats were given diets containing 0 (control) or 3% uracil for 104 wk. In the uracil-treated groups, carcinomas, in particular transitional cell carcinomas, developed in the urinary bladder of 90% of the males and 19% of the females. Squamous cell carcinomas also developed in 10% of the males, but not in females. Striking findings w...

0.4 Background and Motivation In living organism’s uracil DNA glycosylases (UDG) are used to prevent mutagenesis by eliminating uracil from DNA molecules by cleaving the N-glycosylic bond (Krokan et al., 2002). Uracil can be found in DNA due to misincorporation of dUMP residues or cytosine deamination (Lindahl, 1993). UDG is used in uracil-excision based cloning invented in the beginning of the...

Kinetic parameters for uracil DNA glycosylase (E. coli)-catalysed excision of uracil from DNA oligomers containing dUMP in different structural contexts were determined. Our results show that single-stranded oligonucleotides (unstructured) are used as somewhat better substrates than the double-stranded oligonucleotides. This is mainly because of the favourable Vmax value of the enzyme for singl...

An open reading frame, BamHI D6R, from the central highly conserved region of the Shope fibroma virus (SFV) genome was sequenced and found to have significant homology to that of uracil DNA glycosylases from a number of organisms. Uracil DNA glycosylase catalyzes the initial step in the repair pathway that removes potentially mutagenic uracil from duplex DNA. The D6R polypeptide was expressed i...

Uracil-DNA glycosylase was partially purified from HeLa cells. Various substrates containing [3H]dUMP residues were prepared by nick-translation of calf thymus DNA. The standard substrate was double-stranded DNA with [3H]dUMP located internally in the chain. Compared to the release of uracil from this substrate, a 3-fold increase in the rate was seen with single-stranded DNA, and a 20-fold redu...

All metazoan guts are subjected to immunologically unique conditions in which an efficient antimicrobial system operates to eliminate pathogens while tolerating symbiotic commensal microbiota. However, the molecular mechanisms controlling this process are only partially understood. Here, we show that bacterial-derived uracil acts as a ligand for dual oxidase (DUOX)-dependent reactive oxygen spe...

Morris, George K. (University of Georgia, Athens), and William L. Williams. Inhibition of growth of Lactobacillus bulgaricus by purine deoxyribonucleotides. J. Bacteriol. 90:715-719. 1965.-An inhibition of growth of Lactobacillus bulgaricus GS was observed with deoxyadenylic acid and deoxyguanylic acid. Deoxynucleotides of cytosine, thymine, and uracil, and the deoxynucleosides of adenine, guan...

Excision of uracil from tetraloop hairpins and single stranded ('unstructured') oligodeoxyribonucleotides by Escherichia coli uracil DNA glycosylase has been investigated. We show that, compared with a single stranded reference substrate, uracil from the first, second, third and the fourth positions of the loops is excised with highly variable efficiencies of 3.21, 0.37, 5.9 and 66.8%, respecti...

Deamination of cytosine residues contributes to the appearance of uracil in DNA. Uracil DNA glycosylase (UDG) initiates uracil excision repair to safeguard the genomic integrity. To study the mechanism of uracil excision in mycobacteria (organisms with G+C rich genomes), we have purified UDG from Mycobacterium smegmatis by more than 3000-fold. The molecular mass of M. smegmatis UDG, as determin...