Unusually Broad Substrate Tolerance of a Heat-Stable Archaeal Sugar Nucleotidyltransferase for the Synthesis of Sugar Nucleotides

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Abstract
Herein, we report the first cloning, recombinant expression, and synthetic utility of a sugar nucleotidyltransferase from any archaeal source and demonstrate by an electrospray ionization mass spectrometry (ESI-MS)-based assay its unusual tolerance of heat, pH, and sugar substrates. The metal-ion-dependent enzyme from Pyrococcus furiosus DSM 3638 showed a relatively high degree of acceptance of glucose-1-phosphate (Glc1P), mannose-1-phosphate (Man1P), galactose-1-phosphate (Gal1P), fucose-1-phosphate, glucosamine-1-phosphate, galactosamine-1-phosphate, and N-acetylglucosamine-1-phosphate with uridine and deoxythymidine triphosphate (UTP and dTTP, respectively). The apparent Michaelis constants for Glc1P, Man1P, and Gal1P are 13.0 +/- 0.7, 15 +/- 1, and 22 +/- 2 microM, respectively, with corresponding turnover numbers of 2.08, 1.65, and 1.32 s(-1), respectively. An initial velocity study indicated an ordered bi-bi catalytic mechanism for this enzyme. The temperature stability and inherently broad substrate tolerance of this archaeal enzyme promise an effective reagent for the rapid chemoenzymatic synthesis of a range of natural and unnatural sugar nucleotides for in vitro glycosylation studies and highlight the potential of archaea as a source of new enzymes for synthesis.