Magdalena Petrová

Structural diversity of nucleoside phosphonic acids as a key factor in the discovery of potent inhibitors of rat T-cell lymphoma thymidine phosphorylase.

Structurally diverse, sugar-modified, thymine-containing nucleoside phosphonic acids were evaluated for their ability to inhibit thymidine phosphorylase (TP, EC 2.4.2.4) purified from spontaneous T-cell lymphomas of an inbred Sprague-Dawley rat strain. From a large set of tested compounds, among them a number of pyrrolidine-based derivatives, 10 nucleotide analogues with IC(50) values below 1 microM were selected. Out of them, four compounds strongly inhibited the enzyme with IC(50) values lying in a range of 11-45 nM. These most potent compounds might be bi-substrate analogues.

Chiral Phosphonate Internucleotide Linkage: A Promising Modification for Chimeric Oligonucleotides?

We have synthesized two different groups of oligonucleotides containing chiral isopolar nonisosteric phosphonate internucleotide linkages, and studied their properties in combination with natural phosphodiester ones. The improved synthetic procedures for the monomers preparation are also reported.

Synthesis of 4'-Methoxy 2'-Deoxynucleoside Phosphoramidites for Incorporation into Oligonucleotides.

This unit contains detailed synthetic protocols for the preparation of 4′‐methoxy 2′‐deoxynucleoside phosphoramidite monomers for A, G, C, T, and U. First, 3′‐silyl‐protected 2′‐deoxynucleosides (dNs) are converted in two steps to 4′,5′‐enol acetates as the key starting compounds. Next, 4′‐methoxy dNs are prepared by a one‐pot procedure comprising N‐iodosuccinimide‐promoted methoxylation, hydrolysis, and reduction of the formed intermediates. Finally, 3′‐phosphoramidites of 4′‐methoxy dNs are obtained by a routine three‐step procedure. Title phosphoramidite monomers are suitable for the synthesis of oligonucleotides on solid phase according to conventional amidite chemistry. 4′‐Methoxy substitution represents a simple modification of the sugar part of dNs, where β‐D‐erythro epimers preferentially adopt N‐type (C3′‐endo, RNA‐like) conformation. Moreover, it imparts superior chemical stability, nuclease resistance, and excellent hybridization properties to modified 4′‐methoxyoligodeoxynucleotides. The strong tendency toward RNA‐selective hybridization suggests its potential utilization in antisense and/or RNAi technologies.