FIG 3.

Analysis of the SPS and SPP activities of SPS₇₉₄₂ and its variants (a and b) and schematic illustration of the functional architecture and conserved motifs of SPS₇₉₄₂ (c). In panel a, fructose-6-phosphate and UDP-glucose were used as the substrates (5 mM each) to determine the bifunctional activity of SPS₇₉₄₂. In panel b, sucrose-6-phosphate (5 mM) was used to examine the SPP activity of SPS₇₉₄₂. All assays were performed in the presence of 200 mM NaCl. The generated sucrose was examined by ion-exchange chromatography. The assay buffer and empty plasmid pRSFDuet-1 were used as negative controls (n.c.). AP (alkaline phosphatase; NEB, Ipswich, MA) was used as a positive control. In panel c, the underlined amino acids were replaced.