Site-Selective Ribosylation of Fluorescent Nucleobase Analogs Using Purine-Nucleoside Phosphorylase as a Catalyst: Effects of Point Mutations
by
Alicja Stachelska-Wierzchowska 1,*
, Jacek Wierzchowski 1, Agnieszka Bzowska 2 and Beata Wielgus-Kutrowska 2
Alicja Stachelska-Wierzchowska 1,*, Jacek Wierzchowski 1, Agnieszka Bzowska 2 and Beata Wielgus-Kutrowska 2
1
Department of Physics and Biophysics, University of Varmia & Masuria in Olsztyn, 4 Oczapowskiego St., 10-719 Olsztyn, Poland
2
Division of Biophysics, Institute of Experimental Physics, University of Warsaw, Zwirki i Wigury 93, 02-089 Warsaw, Poland
*
Author to whom correspondence should be addressed.
Academic Editor: Mahesh K. Lakshman
Molecules 2016, 21(1), 44; https://doi.org/10.3390/molecules21010044
Received: 13 November 2015 / Revised: 7 December 2015 / Accepted: 9 December 2015 / Published: 28 December 2015
(This article belongs to the Special Issue Nucleoside Modifications)
Enzymatic ribosylation of fluorescent 8-azapurine derivatives, like 8-azaguanine and 2,6-diamino-8-azapurine, with purine-nucleoside phosphorylase (PNP) as a catalyst, leads to N9, N8, and N7-ribosides. The final proportion of the products may be modulated by point mutations in the enzyme active site. As an example, ribosylation of the latter substrate by wild-type calf PNP gives N7- and N8-ribosides, while the N243D mutant directs the ribosyl substitution at N9- and N7-positions. The same mutant allows synthesis of the fluorescent N7-β-d-ribosyl-8-azaguanine. The mutated form of the E. coli PNP, D204N, can be utilized to obtain non-typical ribosides of 8-azaadenine and 2,6-diamino-8-azapurine as well. The N7- and N8-ribosides of the 8-azapurines can be analytically useful, as illustrated by N7-β-d-ribosyl-2,6-diamino-8-azapurine, which is a good fluorogenic substrate for mammalian forms of PNP, including human blood PNP, while the N8-riboside is selective to the E. coli enzyme.
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Keywords:
fluorescent nucleosides; enzymatic ribosylation; 8-azapurines; purine nucleoside phosphorylase
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MDPI and ACS Style
Stachelska-Wierzchowska, A.; Wierzchowski, J.; Bzowska, A.; Wielgus-Kutrowska, B. Site-Selective Ribosylation of Fluorescent Nucleobase Analogs Using Purine-Nucleoside Phosphorylase as a Catalyst: Effects of Point Mutations. Molecules 2016, 21, 44.
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