The maturation of transfer RNA (tRNA) involves extensive chemical modification of the constituent nucleosides and results in the introduction of significant chemical diversity to tRNA. Many of the pathways to these modified nucleosides are characterized by chemically complex transformations, some of which are unprecedented in other areas of biology. To illustrate the scope of the field, recent ...

A rapid technique for quantitative separation of ribose-methylated nucleosides from base-methylated and non-methylated nucleosides by chromatography on DEAE-cellulose paper in the presence of borate is described. The method has been used as an assay for tRNA ribose methylases from yeast, using under methylated Escherichia coli tRNA as substrate. The main product formed with a partly purified ye...

The syntheses of novel hydrazono acyclic nucleosides similar to miconazole scaffolds are described. In this series of acyclic nucleosides, pyrimidine as well as purine and other azole derivatives replaced the imidazole function in miconazole and the ether group was replaced with a hydrazone moiety using phenylhydrazine. To interpret the dominant formation of (E)-hydrazone derivatives rather tha...

The antiviral activity of certain acyclic nucleosides drew our attention to the fact that the replacement of the furanose ring by an alkyl group bearing hydroxyl(s) could be a useful structural modification to modulate the biological properties of those nucleosides. Herein, we report on the synthesis of some novel acadesine analogues, where the ribose moiety is mimicked by a D-ribityl or by a h...

Transport of pyrimidine nucleosides into germinating Petunia hybrida pollen is carrier-mediated, and, except for thymidine, is inhibited by the energy poisons N,N'-dicyclohexylcarbodiimide, 7-chloro-4-nitrobenzo-2-oxa-1,3-diazole, 2,4-dinitrophenol, and carbonylcyanide-m-chlorophenylhydrazone. Kinetic studies with analogs deoxyuridine and 5-bromodeoxyuridine show that they too are taken up fast...

5-(Octa-1,7-diynyl)-2'-deoxyuridine was converted into the furano-dU derivative 7 by copper-catalyzed cyclization; the pyrolodC-derivative 3 was formed upon ammonolysis. The bicyclic nucleosides 3 and 7 as well as the corresponding non-cyclic precursors 4 and 6 all containing terminal C[triple bond]C bonds were conjugated with the non-fluorescent 3-azido-7-hydroxycoumarin 5 employing the copper...

A previous report from this laboratory indicated that the concentration of free uridine (Urd) in many normal murine tissues greatly exceeds that in plasma. We now report that Urd uptake by isolated murine splenocytes is concentrative, and that the rate of uptake from medium containing 10 to 500 microM [3H]Urd conforms to a process that is saturable with a Km of 38.0 +/- 4.1 (SE) microM and Vmax...

L-nucleoside analogs represent an important class of small molecules for treating both viral infections and cancers. These pro-drugs achieve pharmacological activity only after enzyme-catalyzed conversion to their tri-phosphorylated forms. Herein, we report the crystal structures of human deoxycytidine kinase (dCK) in complex with the L-nucleosides (-)-beta-2',3'-dideoxy-3'-thiacytidine (3TC)--...