Fig 3.

Cps2G glucosyltransferase activity. (A) Cps2E-, Cps2T-, and Cps2F-containing membranes (3 μg of total protein each) were incubated with UDP-[¹⁴C]Glc, dTDP-Rha, and membranes containing Cps2G, Cps2I, or a membrane control (MC; 3 μg of total protein from vector-only E. coli strain RC124). Reaction conditions are as indicated for Fig. 2. (B) Cps2G activity in the absence of Cps2E, Cps2T, and Cps2F. The extracted Cps2F glycolipid product (Und-P-P-[¹⁴C]Glc-Rha-Rha-Rha) was incubated with membranes containing Cps2G or membrane controls in the presence of UDP-Glc or dTDP-Rha. Reaction mixtures contained 3 μg of total membrane protein, 0.008% NP-40, 10 mM MnCl₂, 1 mM DTT, 25 μl of the Und-P-P-[¹⁴C]Glc-Rha-Rha-Rha solution (see Materials and Methods), and 0.1 mM dTDP-Rha or 0.1 mM UDP-Glc. Reactions were processed as described above. Lanes show enzymes in the reaction mixtures: MC, membrane control; G, Cps2G; and I, Cps2I. Arrows indicate the locations of the origin (O) and the products formed by Cps2E, Cps2T, Cps2F, and Cps2G.