Electron attachment to trimeric complexes that mimic most frequent hydrogen bonding interactions between an amino acid side chain (AASC) and the Watson-Crick (WC) 9-methyladenine-1-methylthymine (MAMT) base pair has been studied at the B3LYP/6-31++G(d,p) level of theory. Although the neutral trimers will not occur in the gas phase due to unfavorable free energy of stabilization (G(stab)) they s...

The time course of removal of thymine by thymine DNA glycosylase has been measured in vitro. Each molecule of thymine DNA glycosylase removes only one molecule of thymine from DNA containing a G.T mismatch because it binds tightly to the apurinic DNA site left after removal of thymine. The 5'-flanking base pair to G.T mismatches influences the rate of removal of thymine: kcat values with C.G, T...

Reprogramming of mammalian genome methylation is critically important but poorly understood. Klf4, a transcription factor directing reprogramming, contains a DNA binding domain with three consecutive C2H2 zinc fingers. Klf4 recognizes CpG or TpG within a specific sequence. Mouse Klf4 DNA binding domain has roughly equal affinity for methylated CpG or TpG, and slightly lower affinity for unmodif...

We have investigated the pharmacokinetics of thymidine (dThd), thymine, and fluorouracil (FUra) over a range of doses in normal dogs. Evidence was obtained to show that the metabolic elimination of these pyrimidines is saturable, resulting in nonlinear pharmacokinetic behavior. Additionally, dThd and thymine were shown to inhibit the catabolism of FUra. Following i.v. infusion to IOW-/ÕMsteady...

A hyperimmune rabbit antiserum to ultraviolet-irradiated DNA was observed to contain two activities directed against irradiated DNA. Radioimmunoassay studies demonstrated that both antigenic determinants were pyrimidine dimers as evidenced by the reduction in antibody binding to enzymatically photoreactivated irradiated DNA. Enzymatic photoreactivation specifically monomerizes pyrimidine dimers...

DNA was isolated from Drosophila melanogaster larvae fed radioactive thymidine (TdR), bromodeoxyuridine (BUdR), or one of these nucleosides together with 5-fluorouracil (FU) under identical conditions. The four DNA samples designated T-DNA, B-DNA, T(F)-DNA, and B(F)-DNA respectively were hydrolyzed with formic acid-diphenylamine, and the pyrimidine oligonucleotides of various chain lengths (iso...

We have investigated the effect of microsolvation on the low-lying pure shape π* resonances of thymine. Static-exchange R-matrix calculations for elastic electron scattering from microhydated thymine, i.e., Thy-(H2O)n with n = 1,2,3,5 are discussed. We look at the additive effect of water molecules hydrogen-bonding to thymine. The results for Thy-(H2O)5 show that both π* resonances appear at lo...

The K562 cell line has been proposed as a useful experimental system to identify anti-tumor compounds acting by inducing terminal erythroid differentiation. K562 cells exhibit a low proportion of hemoglobin-synthesizing cells under standard cell growth conditions, but are able to undergo terminal erythroid differentiation when treated with a variety of anti-tumor compounds. In this paper we rep...

We have investigated the pharmacokinetics of thymidine (dThd), thymine, and fluorouracil (FUra) over a range of doses in normal dogs. Evidence was obtained to show that the metabolic elimination of these pyrimidines is saturable, resulting in nonlinear pharmacokinetic behavior. Additionally, dThd and thymine were shown to inhibit the catabolism of FUra. Following i.v. infusion to low-microM ste...

In Paper I (l), it was shown that, in Escherichia co&, exogenous uracil can be converted to nucleic acid thymine and that the methyl group of methionine does not serve as a precursor of either bacterial thymine or bacteriophage thymine and hydroxymethylcytosine. Considerations as to the nature of the l-carbon precursor of the thymine methyl group and of possible biosynthetic mechanisms have led...