Information about the molecular biology of the uracil carrier of Saccharomyces cerevisiae is now available but its properties as a symport are unexplored. We have now studied its proton stoichiometry at pH 6.5, 4.8 and 4.2, in a yeast strain overexpressing the symport and unable to metabolize uracil. After the depletion of cellular ATP, uracil uptake followed an approximately exponential time c...

The synthesis of the pyrimidinyl amino acids willardiine and isowillardiine was studied in vivo and in vitro. Uracil derivatives stimulate the biosynthesis of both compounds; the free base is the most effective. Significant incorporation of [2-(14)C]uracil and [6-(14)C]orotate into willardiine and isowillardiine was found. Incorporation of [6-(14)C]orotate was substantially decreased in the pre...

Archaeal family B polymerases bind tightly to the deaminated bases uracil and hypoxanthine in single-stranded DNA, stalling replication on encountering these pro-mutagenic deoxynucleosides four steps ahead of the primer-template junction. When uracil is specifically bound, the polymerase-DNA complex exists in the editing rather than the polymerization conformation, despite the duplex region of ...

aminofluorene for 90 days have a 10-fold increased capac ity to incorporate uracil into the ribonucleic acids in vivo (2, 16). According to current views (1, 6), the incorpora tion is determined by the activity of the anabolic as well as the catabolic enzyme systems involved in uradil metabo lism. The increased incorporation of uracil might thus be due, at least in part, to a decreased capacity...

aminofluorene for 90 days have a 10-fold increased capac ity to incorporate uracil into the ribonucleic acids in vivo (2, 16). According to current views (1, 6), the incorpora tion is determined by the activity of the anabolic as well as the catabolic enzyme systems involved in uradil metabo lism. The increased incorporation of uracil might thus be due, at least in part, to a decreased capacity...

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...

Uracil-DNA glycosylase, the enzyme responsible for the removal of uracil from DNA (1), is directly involved in mutation avoidance (2). Indeed, it is likely to prevent transition mutations by removing uracil that results from deamination of cytosine. It has been proposed that the removal of misincorporated uracil by uracil-DNA glycosylase also plays an indirect role in correction of replication ...

In the title molecule, C(16)H(13)ClO(3)S, the 3-chloro-phenyl ring makes a dihedral angle of 76.30 (5)° with the mean plane of the benzofuran fragment. In the crystal, pairs of inter-molecular C-H⋯π inter-actions link the mol-ecules into inversion dimers.

* Reductive catabolism of pyrimidine nucleotides occurs via a three-step pathway in which uracil is degraded to beta-alanine, CO(2) and NH(3) through sequential activities of dihydropyrimidine dehydrogenase (EC 1.3.1.2, PYD1), dihydropyrimidinase (EC 3.5.2.2, PYD2) and beta-ureidopropionase (EC 3.5.1.6, PYD3). * A proposed function of this pathway, in addition to the maintenance of pyrimidine h...