Phosphomannose isomerase/GDP-mannose pyrophosphorylase from Pyrococcus furiosus: a thermostable biocatalyst for the synthesis of guanidinediphosphate-activated and mannose-containing sugar nucleotides.

Herein we present an analysis of the chemical function of a recombinant bifunctional phosphomannose isomerase/GDP-mannose pyrophosphorylase (manC) from Pyrococcus furiosus DSM 3638 and its use in the synthesis of guanidinediphospho-hexoses and a range of nucleotidediphospho-mannoses. This enzyme is unusually promiscuous in both its nucleotide triphosphate (NTP) and sugar-1-phosphate acceptance. It accepts all five naturally occurring NTPs (ATP, CTP, GTP, dTTP and UTP) and a range of sugar-1-phosphates (glucose-, mannose-, galactose-, glucosamine-, N-acetylglucosamine- and fucose-1-phosphate). A truncated GDP-mannose pyrophosphorylase domain of the whole length enzyme showed almost 100-fold less sugar nucleotidyltransferase activity with only GTP and mannose 1-phosphate as substrates. The temperature stability and inherently broad substrate tolerance of this archaeal enzyme make it an effective reagent for the rapid chemoenzymatic synthesis of a range of natural and unnatural sugar nucleotides that are challenging to make by chemical means alone.