Figure 4

Addition of chemicals for increasing solubility of DXS and production of deoxyxylulose phosphate (DXP). Chemicals with different properties were used to increase solubility of dxs. The expression system (araBAD promoter-DH10B strain) and the temperature (20°C) which produced the most soluble DXS were used here. The use of high concentration of sorbitol was found to significantly increase solubility of DXS and production of DXP (product of DXS). A: Effects of the chemical additions on solubility of DXS; B: Illustration of increased protein solubility by sorbitol, S: soluble fraction, IS: insoluble fraction; the arrowed band was DXS; C: Effects of sorbitol addition on production of DXP; addition of sorbitol increased DXP production in the cells expressing DXS but not in the ones expressing DXS (R398A), a nonfunctional mutant. Presented data were average of triplicates and standard errors were drawn on the plot. Student’s t-test was used to calculate the p values in the statistical analysis.