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Updated: Jun 27, 2025

Nucleoside Triphosphates - From Synthesis to Biochemical Characterization
Published on: April 3, 2014
Nucleoside Phosphorylases make N7-xanthosine
Sarah Westarp1,2, Felix Brandt3, Lena Neumair1
1Chair of Bioprocess Engineering, Institute of Biotechnology, Faculty III Process Sciences, Technische Universität Berlin, Ackerstrasse 76, 13355, Berlin, Germany.
Abstract:
Modern, highly evolved nucleoside-processing enzymes are known to exhibit perfect regioselectivity over the glycosylation of purine nucleobases at N9. We herein report an exception to this paradigm. Wild-type nucleoside phosphorylases also furnish N7-xanthosine, a "non-native" ribosylation regioisomer of xanthosine. This unusual nucleoside possesses several atypical physicochemical properties such as redshifted absorption spectra, a high equilibrium constant of phosphorolysis and low acidity. Ultimately, the biosynthesis of this previously unknown natural product illustrates how even highly evolved, essential enzymes from primary metabolism are imperfect catalysts.
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