FIG. 2.

Improvement of expression levels and solubilities of human proteins by the PrS₂ tag. (a) Expression of PrS₂-tagged human proteins. The PrS₂ tag is fused to human proteins that were expressed at low levels or in insoluble forms by a pET system or pCold His₆ tag. Each PrS₂-tagged protein was expressed at 15°C and room temperature (RT) for 14 h, and cell pellets were examined by SDS-PAGE. The sample at 0 h (before protein induction) was used as a negative control. (b) The solubilities of PrS₂-tagged proteins for which expression patterns are shown in panel a were examined. S, soluble fraction; I, insoluble fraction. Asterisks indicate the corresponding proteins in panels a and b.