Synthesis of acid stable 5′-o-fluoromethyl phosphonates of nucleosides. Evaluation as inhibitors of reverse transcriptase

Glycomimetics Targeting Glycosyltransferases: Synthetic, Computational and Structural Studies of Less-Polar Conjugates

The Leloir donors are nucleotide sugars essential for a variety of glycosyltransferases (GTs) involved in the transfer of a carbohydrate to an acceptor substrate, typically a protein or an oligosaccharide. A series of less-polar nucleotide sugar analogues derived from uridine have been prepared by replacing one phosphate unit with an alkyl chain. The methodology is based on the radical hydrophosphonylation of alkenes, which allows coupling of allyl glycosyl compounds with a phosphate unit suitable for conjugation to uridine. Two of these compounds, the GalNAc and galactose derivatives, were further tested on a model GT, such as GalNAc-T2 (an important GT widely distributed in human tissues), to probe that both compounds bound in the medium-high micromolar range. The crystal structure of GalNAc-T2 with the galactose derivative traps the enzyme in an inactive form; this suggests that compounds only containing the β-phosphate could be efficient ligands for the enzyme. Computational studies with GalNAc-T2 corroborate these findings and provide further insights into the mechanism of the catalytic cycle of this family of enzymes.

Modified nucleotides as substrates and inhibitors of adenylate kinase from different sources

The substrate and inhibitory properties of modified nucleotides with respect to adenylate kinase from rabbit muscles, human placenta and Escherichia coli were studied. A number of 5'-hydrogenphosphonates and 5'-fluorophosphates of modified nucleotides were shown to inhibit the phosphorylation reaction catalyzed by these enzymes. A clear difference between phosphonates of 3'-deoxyribonucleotides and the corresponding ribo- and 2',3'-dideoxyribonucleotides was found. 3'-Azido-2',3'-dideoxythymidine and its phosphorus derivatives did not inhibit the adenylate kinase reaction.