High-yielding cascade enzymatic synthesis of 5-methyluridine using a novel combination of nucleoside phosphorylases

Abstract

A novel combination of Bacillus halodurans purine nucleoside phosphorylase (BhPNP1) and Escherichia coli uridine phosphorylase (EcUP) has been applied to a dual-enzyme, sequential, biocatalytic one-pot synthesis of 5-methyluridine from guanosine and thymine. A 5-methyluridine yield of >79% on guanosine was achieved in a reaction slurry at a 53 mM (1.5% w/w) guanosine concentration. 5-Methyluridine is an intermediate in synthetic routes to thymidine and the antiretroviral drugs zidovudine and stavudine.

Keywords::

• Purine nucleoside phosphorylase
• uridine phosphorylase
• biocatalysis
• 5-methyluridine
• fermentation
• transglycosylation

Acknowledgements

The authors would like to thank N. Gumede, S. Ramchuran (LIFElab), R. Lalloo, C. van der Westhuyzen, V. Moodley, K. Pillay, D. Mabena, S. Machika and H. Manchidi (CSIR Biosciences) for technical assistance. They gratefully acknowledge Dr D. R. Walwyn (CEO of Arvir Technologies) and Dr H. Roman (CSIR) for management of the project. Financial support for this work was provided by CSIR Biosciences, LIFElab, DST and Arvir Technologies. Thanks also go to Professor D. Litthauer (University of the Free State) for the K. pneumoniae and B. licheniformis cultures. This paper is dedicated to the analytical chemist and colleague Mr Simon Machika, who passed away during this research.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.