FIGURE 3.
An α6GlcT elongates N-linked glucose. A, glucosylated TAMRA-labeled peptides were incubated with α6GlcT and different UDP-monosaccharide donors and then separated by Tricine/SDS-PAGE. B, MALDI-MS analysis of glucosylated products showed that the glucosyltransferase added two units of glucose to the N-glucose. C, HSQC spectrum showing 13C-1H correlations of TAMRA-DANYTK-Glc3. Signals of three different glucose species are visible. GlcT, terminal glucose; GlcB, bridging glucose; GlcA, N-linked glucose. D, 1H-1H TOCSY spectrum (120-ms mixing time, D2O) allows identification of the different glucose species within the sample. The signal labeled with an asterisk might come from a second signal set for a bridging glucose different from GlcB.