In the title mol-ecule, C(5)H(6)BrN(3), the pyrimidine ring is essentially planar, with an r.m.s. deviation of 0.007 Å. The Br and N atoms substituted to the pyrimidine ring are coplanar with the ring [displacements = 0.032 (1) and 0.009 (5) Å, respectively], while the methyl C atom lies 0.100 (15) Å from this plane with a dihedral angle between the pyrimidine ring and the methyl-amine group of...

The effect of purified Escherichia coli DNA photolyase on the UV light-induced pyrimidine-pyrimidone (6-4) photoproduct and cyclobutane pyrimidine dimer was investigated in vitro using enzyme purified from cells carrying the cloned phr gene (map position, 15.7 min). Photoproducts were examined both as site-specific lesions in end-labeled DNA and as chromatographically identified products in uni...

Various purine and pyrimidine ribosides, with the exception of adenosine, have been found to exhibit a positive inotropic effect on an isolated strip of frog ventricle. Li a preparation responding maximally to one compound, the addition of a second compound led to a further increase in tension. This relationship was found to apply among the members of a given group (purine or pyrimidine) paired...

Reaction of heteroaromatic o-aminonitrile with ethyl N-[bis(methylthio)methylene]amino acetate resulted in annelation of a thieno[3,2-e]imidazo[1,2-c]pyrimidine moiety in a one step process. [1,2,4]Triazolo[4,3-c]thieno- [3,2-e]pyrimidine derivatives were prepared by initial treatment of o-aminonitrile with carbon disulfide, followed by methylation with methyl iodide and subsequent reaction wit...

Various symmetries connected with purine-pyrimidine content of DNA sequences are studied in terms of the intruduced determinative degree, a new characteristics of nucleotide which is connected with codon usage. A numerological explanation of CG pressure is proposed. A classification of DNA sequences is given. Calculations with real sequences show that purine-pyrimidine symmetry increases with g...

The asymmetric unit of title compound, C(7)H(6)N(4)·C(6)H(6)O(2), contains one 5-(1H-imidazol-1-yl)pyrimidine mol-ecule and two half benzene-1,4-diol mol-ecules; the benzene-1,4-diol mol-ecules are located on individual inversion centers. In the pyrimidine mol-ecule, the imidazole ring is twisted with respect to the pyrimidine ring at a dihedral angle of 25.73 (7)°. In the crystal, O-H⋯N hydrog...

Modified urinary nucleosides are potentially invaluable in cancer diagnosis, as they reflect altered RNA turnovers. High-performance liquid chromatography (HPLC) was combined with full-scan mass spectrometry, tandem mass spectrometry, MS(n) analysis and accurate mass measurements in order to identify pyrimidine nucleosides purified from urine. Potential nucleosides were assessed by their eviden...

Somatic and oocyte 5S rRNAs from the liver and unfertilized eggs of the loach (Misgurnus fossilis have been sequenced and found to differ in six nucleotides. All the substitutions are confined to the 5'-half of the molecules; 4 of them are pyrimidine-pyrimidine substitutions, and 2 are purine-pyrimidine ones. Considerable differences, both in the position and the character of substitutions, hav...

The asymmetric unit of the title compound, [Zn(NCSe)(2)(C(4)H(4)N(2))(2)](n), consists of one Zn(2+) cation located on a special position with site symmetry 2/m, one seleno-cyanate anion on a mirror plane and one pyrimidine ligand on a twofold rotation axis. The zinc cation is coordinated by six N atoms of four pyrimidine ligands and two N-bonded seleno-cyanate anions in mutually trans orientat...