Peptide nucleic acid (PNA) is a synthetic analogue of DNA that commonly has an N-aminoethyl glycine backbone. The crystal structures of two PNA duplexes, one containing eight standard nucleobase pairs (GGCATGCC)(2), and the other containing the same nucleobase pairs and a central pair of bipyridine ligands, have been solved with a resolution of 1.22 and 1.10 Å, respectively. The non-modified PN...

The effect of N-aglycones at C1’ on the drive of two-state north (N (C3’-endo-C2’-exo)) * south ( S (C2’endo-C3’-exo)) pseudorotational equilibrium in 8-D-ribofuranosyl-N-nucleosides consists of two counteracting contributions from (i) the anomeric effect (stereoelectronic interactions between furanose 04’ and the nucleobase nitrogen at Cl’), which places the aglycone in the pseudoaxial orienta...

An electroorganic reaction for the synthesis of 7-amino-2, 4-dioxo-5-phenyl-2,3,4,5-tetrahydro-1H-pyrano[2, 3-d] pyrimidine-6-carbonitrile and ethyl-7-amino-2, 4-dioxo-5-phenyl-2,3,4,5-tetrahydro-1H-pyrano[2, 3-d] pyrimidine-6-carboxylate derivatives are described, using an electrogenerated base of the anion of malonitrile or ethylcyanoacetate. This one-pot, three-component condensation of an a...

In an endeavor to find a novel series of antihyperglycemic agents, new benzimidazole and pyrimidine derivatives were successfully synthesized efficiently in high yield with high purity, starting from amino acids in the presence of phosphorus oxychloride (POCl3). The synthesized compounds were identified by 1H-NMR, 13C-NMR, FT-IR spectroscopic techniques and elemental analysis. All products were...

We report a crystal structure that shows an antibiotic that extracts a nucleobase from a DNA molecule 'caught in the act' after forming a covalent bond but before departing with the base. The structure of trioxacarcin A covalently bound to double-stranded d(AACCGGTT) was determined to 1.78 A resolution by MAD phasing employing brominated oligonucleotides. The DNA-drug complex has a unique struc...

The synthesis of nucleoside analogues incorporating 4-(5-pyrimidinyl)-1,2,3-triazole aglycons as expanded purine nucleobase mimics were accessed using the copper-catalyzed azide-alkyne Huisgen cycloaddition between a ribosyl azide and 5-alkynylpyrimidines. Depending on the nature of the alkyne employed, other nucleoside analogues that possess fluorescence or potential metal-binding properties w...

Pyrimidines represent an important class of heterocycles containing two nitrogen atoms at position 1 and 3 the six membered ring show wide range biological activities. Numerous methods for synthesis pyrimidine their diverse reactions offer enormous scope in field medicinal chemistry. Pyrimidine possesses spectrum activities including antitubercular, antibacterial, antifungal, antiviral, anti-in...

Mg2+ and Mn2+ ions are critical to the functioning of phosphoryl transfer enzymes, such as restriction endonucleases. Although these ions play similar roles in the chemical steps, they govern substrate specificity via modulating sequence discrimination by up to a factor of 10(5) with Mg2+ and only up to a factor of 10 with Mn2+. To explain whether such diversity originates in fundamental differ...

Protozoan parasites of the Leishmania genus express the metabolic machinery to synthesize pyrimidine nucleotides via both de novo and salvage pathways. To evaluate the relative contributions of pyrimidine biosynthesis and salvage to pyrimidine homeostasis in both life cycle stages of Leishmania donovani, individual mutant lines deficient in either carbamoyl phosphate synthetase (CPS), the first...