Enzymatic Synthesis of Highly Fluorescent 8-Azapurine Ribosides Using a Purine Nucleoside Phosphorylase Reverse Reaction: Variable Ribosylation Sites

Stachelska-Wierzchowska, Alicja; Wierzchowski, Jacek; Wielgus-Kutrowska, Beata; Mikleušević, Goran (2013) Enzymatic Synthesis of Highly Fluorescent 8-Azapurine Ribosides Using a Purine Nucleoside Phosphorylase Reverse Reaction: Variable Ribosylation Sites. Molecules, 18 (10). pp. 12587-12598. ISSN 1420-3049

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Official URL: https://doi.org/10.3390/molecules181012587

Abstract

Various forms of purine-nucleoside phosphorylase (PNP) were used as catalysts of enzymatic ribosylation of selected fluorescent 8-azapurines. It was found that the recombinant calf PNP catalyzes ribosylation of 2, 6-diamino-8-azapurine in a phosphate-free medium, with ribose-1-phosphate as ribose donor, but the ribosylation site is predominantly N7 and N8, with the proportion of N8/N7 ribosylated products markedly dependent on the reaction conditions. Both products are fluorescent. Application of the E. coli PNP gave a mixture of N8 and N9-substituted ribosides. Fluorescence of the ribosylated 2, 6-diamino-8-azapurine has been briefly characterized. The highest quantum yield, ~0.9, was obtained for N9-β-D-riboside (λmax 365 nm), while for N8-β-D-riboside, emitting at ~430 nm, the fluorescence quantum yield was found to be close to 0.4. Ribosylation of 8-azaguanine with calf PNP as a catalyst goes exclusively to N9. By contrast, the E. coli PNP ribosylates 8-azaGua predominantly at N9, with minor, but highly fluorescent products ribosylated at N8/N7.

Item Type:

Article

Uncontrolled Keywords:

8-azapurines; nucleosides; enzymatic synthesis; fluorescence; purine-nucleoside phosphorylase

Subjects:

NATURAL SCIENCES > Chemistry
NATURAL SCIENCES > Biology

Divisions:

Division of Physical Chemistry

Projects: